Visual rehabilitation with scleral contact lenses in patients with irregular astigmatism

Introduction: Scleral contact lenses (SCLs) are gas-permeable and are placed entirely on the sclera without contacting structures such as the cornea or limbus. These ECLs are designed to rehabilitate reduced vision of eyes with irregular corneas. Irregular astigmatism caused by corneal pathologies such as keratoconus, post-transplant, post-refractive surgery, or corneal degeneration produces poor visual acuity that cannot be corrected with air lenses, and the appearance of scleral contact lenses could be a therapeutic option in the treatment and optical correction of corneal pathologies. To determine the degree of improvement in visual acuity with adaptation of scleral lenses. Methodology: This was an observational, descriptive, retrospective, cross-sectional, retrospective study. Results: Forty cases of irregular astigmatism with different initial visual acuity effects were observed prior to the fitting of Scleral Lenses. The mean visual acuity (VA) prior to correction with scleral lenses observed in the 40 cases was 20/200 with correction on the Snellen scale with a minimum (worst VA) equal to "finger-count vision" (represented as cases with 20/ 400 vision for quantification purposes) and a maximum (best VA) of 20/70. Nineteen cases (47.5%) restored their VA to normal values (20/20), and 30 cases (75%) improved their VA by at least 10-fold from the baseline. Discussion: In this study, a remarkable and constant improvement in visual acuity was observed in all the patients. Some patients experienced an increase of up to 20 times their initial visual acuity, achieving, in many cases, a visual acuity of 20/20 on the Snellen scale. These results indicate a promising treatment strategy with fewer adverse effects.

Introducción: Las lentes de contacto esclerales (LCE) son permeables al gas y se colocan totalmente en la esclera sin hacer contacto con estructuras como la córnea o el limbo. Estas LCE son diseñadas para rehabilitar la visión reducida de los ojos con córneas irregulares. Los astigmatismos irregulares producidos por patologías corneales como el queratocono, post trasplante, post cirugía refractiva o degeneraciones corneales producen una mala agudeza visual que no puede ser corregida con lentes aéreas, actualmente con la aparición de las lentes de contacto esclerales podrían ser una de las opciones terapéuticas en el tratamiento y corrección óptica de las patologías corneales. Determinar el grado de mejoría de la agudeza visual con la adaptación de lentes esclerales. Metodología: Observacional descriptivo de corte transversal, retrospectivo. Resultados: 40 casos de astigmatismo irregular con distintas afectaciones iniciales en la agudeza visual previo a la colocación de las LCE. La media de agudeza visual (AV) previo a la corrección con las lentes esclerales observada en los 40 casos fue de 20/200 con corrección (CC) en la escala de Snellen con un mínimo (peor AV) igual a "visión cuenta dedos" (representado como casos con visión 20/400 con fines de cuantificación) y un máximo (mejor AV) de 20/70. 19 casos (47,5%) restauraron su AV a valores normales (20/20); 30 casos (el 75%) mejoraron su AV al menos 10 veces respecto al valor inicial. Discusión: En este estudio, se observó una notable y constante mejora en la agudeza visual de todos los pacientes estudiados. Algunos pacientes experimentaron aumentos de hasta 20 veces su agudeza visual inicial, logrando en muchos casos una agudeza visual de 20/20 en la escala de Snellen. Estos resultados indican un tratamiento prometedor con pocos efectos adversos evidentes.

Aspectos a considerar para el diagnóstico del queratocono infantil / Aspects to consider for the diagnosis of infant keratoconus

Introducción: Globalmente, existe un aumento de la prevalencia del queratocono y su diagnóstico en edades tempranas. Se notifican un gran número de casos subclínicos y otros con una rápida progresión, condicionada por el inicio precoz de la enfermedad y la asociación a factores de riesgo. Objetivo: Describir los aspectos epidemiológicos, clínicos y el resultado de los medios de diagnóstico implicados en la detección precoz del queratocono infantil. Desarrollo: En niños con ametropía hay elementos que alertan la presencia de un queratocono como causa del defecto refractivo. Desde el punto de vista epidemiológico se encuentran: distribución geográfica, rol de la herencia y factores ambientales. Clínicamente se señalan los antecedentes de enfermedades, tales como las alergias, la presencia de miopía o astigmatismo miópico con inestabilidad refractiva y los signos clínicos relacionados con la progresión del cono. En los pacientes de riesgo es preciso realizar exámenes mediante diferentes medios de diagnóstico según su disponibilidad, siendo primordial el análisis refractivo, queratométrico y topográfico. Conclusiones: En la evaluación de los niños con ametropía se deben tener en cuenta elementos epidemiológicos y clínicos que permiten sospechar y diagnosticar precozmente el queratocono. En la interpretación de los resultados de los medios de diagnóstico involucrados en su detección, se deben considerar los hallazgos más frecuentes en la población infantil según el grado de progresión de la ectasia.

Introduction: Globally, there is an increase of the keratoconus prevalence and its diagnosis in early ages. A great number of subclinical cases and others with a quick progression are notified, conditioned by the early onset of the disease and the association with risk factors. Objective: To describe the epidemiological, clinical aspects and the result of diagnostic means involved in the early detection of infant keratoconus. Development: There are elements that alert the presence of a keratoconus as a cause of the refractive defect in children with ametropia. From the epidemiologic point of view they are: geographical distribution, heredity role and environmental factors. History of previous diseases are clinically pointed out, such as allergies, myopia or myopic astigmatism with refractive instability and the clinical signs related to cone progression. In risk patients it is necessary to carry out exams by means of different diagnostic means according to their availability, being essential the refractive, keratometric and topographic analysis. Conclusions: In the evaluation of children with ametropia, epidemiological and clinical elements should be taken into account that allow to suspect and early diagnose the keratoconus. In the interpretation of results of the diagnostic means involved in their detection the most frequent findings in the infant population, should be considered according to the ectasia degree of progression.

Resultados visuais, topográficos e refrativos do implante de segmentos assimétricos de anel corneano intraestromal em ceratocone / Visual, topographic, and refractive outcomes of the implantation of asymmetric segments of the intrastromal corneal ring in keratoconus

RESUMO Objetivo: Avaliar os resultados visuais, topográficos e refrativos do implante de segmentos assimétricos (AS) de anel intracorneano (ICRS) em olhos com ceratocone e astigmatismo irregular/assimétrico (fenótipos tipo 2 Duck e 3 Snowman pela classificação morfológica do ceratocone de Fernandez-Vega/Alfonso). Métodos: Estudo clínico prospectivo realizado com 60 pacientes (60 olhos) com ceratocone que tiveram segmentos assimétricos de Kearing selecionados e implantados de acordo com o nomograma Mediphacos (http://kearing.online) com laser femtosegundo. As avaliações pré-operatórias e pós-operatórias incluíram medida de acuidade visual não corrigida, melhor acuidade visual corrigida, astigmatismo refracional, equivalente esférico e astigmatismo topográfico, Kmax e coma, medidos com o Galilei (Ziemer, Port, Suíça). Todos os parâmetros foram avaliados no pré-operatório e aos 3 e 6 meses de pós-operatório. Resultados: A média de idade dos pacientes foi de 26,34±8,49 anos; 28 (56,7%) eram do sexo feminino, 34 olhos apresentavam ceratocone de fenótipo tipo 2 e outros 26 olhos de fenótipo tipo 3. Aos 6 meses de pós-operatório, os olhos de fenótipo tipo 2 obtiveram ganhos na acuidade visual não corrigida e melhor acuidade visual corrigida de 0,30 LogMAR e 0,15 LogMAR, respectivamente; e reduções de 2,45D no astigmatismo topográfico; 2,30D no Kmax; 0,32μm no coma; 1,63D no astigmatismo refracional e 1,88D no equivalente esférico. Aos 6 meses, os olhos de fenótipo tipo 3 obtiveram ganhos na acuidade visual não corrigida e na melhor acuidade visual corrigida de 0,50 logMAR e 0,10 LogMAR, respectivamente; e reduções de 3,00D no astigmatismo topográfico; 5,20 D no Kmax; 0,09μm no coma; 2,00D no astigmatismo refracional e 4,25D no equivalente esférico. Os resultados das comparações entre 3 e 6 meses de pós-operatório não foram estatisticamente significativos para nenhuma das variáveis avaliadas, o que denotou a estabilidade do procedimento nesse tempo de seguimento. Conclusão: O implante de segmentos assimétricos de Kearing em olhos com ceratocone e astigmatismo irregular/assimétrico (fenótipos tipo 2 e 3) melhoraram os parâmetros visuais, topográficos e refrativos com segurança e eficácia clínica.

ABSTRACT Purpose: To evaluate the visual, topographic, and refractive outcomes of the implantation of asymmetric segments (AS) of the ICRS intracorneal ring in eyes with keratoconus and irregular/asymmetric astigmatism (phenotypes type 2 Duck and 3 Snowman by morphological classification of Fernandez-Vega/Alfonso Keratoconus). Methods: Prospective clinical study including 60 patients (60 eyes) with keratoconus who underwent implantation of the Kearing ICRS selected and implanted according to the Mediphacos nomogram (http://kearing.online) with femtosecond laser. Preoperative and postoperative evaluations included uncorrected visual acuity, best corrected visual acuity, refractive astigmatism, spherical equivalent, and topographic astigmatism, Kmax, and coma measured with the Galilei (Ziemer, Port, Switzerland). All parameters were assessed preoperatively and at 3 and 6 months postoperatively. Results: Overall mean age was 26.34 ± 8.49 years; 28 (56.7%) were female, 34 eyes had keratoconus of type 2 phenotype and another 26 eyes of type 3 phenotype. At 6 months postoperatively, eyes with type 2 phenotype obtained gains in uncorrected visual acuity and best corrected visual acuity of 0.30 LogMAR and 0.15 LogMAR, respectively; and reductions of 2.45D in topographic astigmatism; 2.30D in Kmax; 0.32μm in coma; 1.63D in refractive astigmatism and 1.88D in spherical equivalent. At 6 months, eyes with type 3 phenotype obtained gains in UDVA and CDVA of 0.50 logMAR and 0.10 LogMAR, respectively; and reductions of 3.00D in topographic astigmatism; 5.20D in Kmax; 0.09μm in coma; 2.00D in refractive astigmatism and 4.25D in spherical equivalent. The results of the comparisons at 3 and 6 months postoperatively were not statistically significant for any of the variables evaluated, which denotes the stability of the procedure in this follow-up time. Conclusion: Implantation of the asymmetric Kearing in eyes with keratoconus and asymmetric/irregular astigmatism (type 2 and 3 phenotypes) improved visual, topographic, and refractive parameters with safety and clinical efficacy.

Evaluation of corneal tomography in children and adolescents without ocular or systemic allergy / Avaliação da tomografia de córnea em crianças e adolescentes sem alergia ocular ou sistêmica

ABSTRACT Purpose: To determine normal corneal tomographic parameters in children and adolescents without corneal disease or atopy diagnosis. Methods: This descriptive cross-sectional study evaluated patients aged 8-16 years who underwent a complete slit-lamp biomicroscopic examination and tomographic corneal evaluation by a dual Scheimpflug analyzer, excluding those with ocular disease (including allergic conjunctivitis) or a positive prick test for systemic atopies. Results: A total of 170 patients were evaluated, and 34 patients (68 eyes) were analyzed once the exclusion criteria were applied. The sample's mean age was 10.76 ± 2.31 years; with 19 (55.9%) men and 15 (44.1%) women. The mean keratometry in the flat meridian (Kflat), steep meridian (Ksteep), and maximum (Kmax) were 42.37 ± 1.63D, 43.53 ± 1.65D, and 43.90 ± 1.73D, respectively. The mean values for corneal asphericity (ε2) and thinnest point were 0.28 ± 0.11 and 550.20 ± 37.90 μm, respectively. The inferior-superior asymmetry ratio (I-S) and coma were 0.74 ±0.59D and 0.28 ± 0.12D, respectively. Conclusion: The knowledge of normal corneal tomographic parameters and their variation in children and adolescents without corneal disease or atopy may be useful for diagnosing keratoconus and initiating early disease treatment.

RESUMO Objetivo: Identificar parâmetros tomográficos de normalidade em córneas de crianças e adolescentes sem a presença de atopias sistêmicas e alergias oculares. Métodos: Este estudo descritivo transversal avaliou pacientes com idade entre 8 e 16 anos que foram submetidos a exame biomicroscópico completo por lâmpada de fenda e avaliação tomográfica da córnea por tomógrafo dual Scheimpflug, excluindo pacientes com doença ocular (incluindo conjuntivite alérgica) ou prick test positivo para atopias sistêmicas. Resultados: Cento e setenta pacientes foram avaliados e após cumpridos os critérios de exclusão, 34 (68 olhos) foram analisados. A média etária da amostra foi 10,76 ± 2,31 anos; 19 (55,9%) eram meninos e 15 (44,1%) meninas. A média da ceratometria em dioptrias (D) no meridiano mais plano (Kflat), mais curvo (Ksteep) e máxima (Kmax) foram 42,37 ± 1,63D, 43,53 ± 1,65D e 43,90 ± 1,73D, respectivamente. Os valores médios da asfericidade corneana (ε2) e do ponto mais fino da córnea foram 0,28 ± 0,11 e 550,20 ± 37,90 micras (μm). A assimetria corneana inferior-superior (I-S) e coma foi em média 0,74 ± 0,59D e 0,28 ± 0,12D, respectivamente. Conclusão: O conhecimento dos valores médios e sua variação de parâmetros tomográficos da córnea em crianças e adolescentes sem atopias sistêmicas ou alergias oculares pode ser útil para o diagnóstico precoce do ceratocone e o seu tratamento em estágio inicial.

Post-Bader procedure: a long-term follow-up case study / Procedimento pós-Bader: estudo de caso com acompanhamento de longo prazo

ABSTRACT Keratoconus is a progressive disorder that manifests as a cone-like steepening of the central or paracentral inferior cornea and irregular stromal thinning. There is a gradual decrease in visual acuity due to corneal asymmetry, irregular astigmatism, and increased optical aberrations, consequently impacting the quality of life. Several procedures have been developed in an attempt to slow or reverse the progression. The Bader procedure, which includes a pattern of incisions around the circumference of the cornea and at the base of the protruding cone, is one such surgery. These incisions penetrate 70-90% of the cornea's depth. Its goal is to flatten the topography and reduce corneal asymmetry and irregular astigmatism. Though prior research found these to be highly promising, we report a patient who was given contact lenses to restore and maintain his vision while his corneal ectasia and thinning progressed over the following decade.

RESUMO O ceratocone é uma doença progressiva que se manifesta como uma elevação semelhante a um cone da cór­nea central ou paracentral inferior e é associada a uma re­dução irregular da espessura do estroma. Há uma diminuição gradual da acuidade visual devido à assimetria da córnea, ao astigmatismo irregular e a um aumento das aberrações ópticas, o que prejudica a qualidade de vida. Foram desenvolvidos vários procedimentos para tentar interromper ou mesmo reverter a evolução da doença. Um deles é o chamado procedimento de Bader, que inclui um padrão de incisões em volta da circunferência da córnea e na base do cone protuberante. Essas incisões penetram até 70%-90% da profundidade da córnea e têm o objetivo de achatar a topografia e diminuir a assimetria da córnea e o astigmatismo irregular. Embora essa técnica seja muito promissora, segundo um estudo anterior, aqui se apresenta o caso de um paciente no qual esses objetivos não foram atingidos. Esse paciente recebeu lentes de contato para restaurar e manter sua visão, enquanto sua ectasia corneana e a redução da espessura progrediram ao longo da década seguinte.

Asimetría interocular en el queratocono pediátrico / Interocular Asymmetry in Pediatric Keratoconus

El queratocono es una ectasia corneal bilateral asimétrica, en etapas iniciales no se evidencia la afectación binocular. El conocimiento del grado de asimetría en el queratocono pediátrico permite tomar decisiones oportunas en el manejo de los pacientes. Se realizó este trabajo con el objetivo de describir las características clínicas y el tratamiento de tres casos pediátricos con diferente grado de asimetría interocular del queratocono, atendidos en la consulta provincial de ectasias corneales pediátricas en Ciego de Ávila. Los pacientes mostraron diferencia entre ambos ojos de los signos clínicos, la refracción y las variables topográficas. Al paciente dos se le diagnosticó queratocono en un ojo, sin evidencias clínicas ni topográficas de la enfermedad en el ojo contralateral. Todos los pacientes mostraron astigmatismo miópico compuesto en ambos ojos y se les indicó corrección óptica. Al paciente uno se le corrigió con cristales, al dos con lentes de contacto rígidos de gas permeable y al tercero con piggyback en un ojo y lentes de contacto rígidos de gas permeable en el otro. Presentaron, además, una ambliopía asociada y se les orientó tratamiento oclusivo y tareas de visión cercana en los pacientes dos y tres. Es frecuente encontrar asimetría interocular en pacientes pediátricos con queratocono por la diferencia de progresión entre ambos ojos. El seguimiento periódico permite diagnosticar la enfermedad en el ojo contralateral en pacientes con diagnóstico de queratocono en un ojo, indicar una corrección óptica individualizada, sobre todo en presencia de anisometropía, y monitorizar la evolución de la ambliopía refractiva asociada con frecuencia(AU)

Keratoconus is an asymmetric bilateral corneal ectasia, in early stages binocular involvement is not evident. Knowledge of the degree of asymmetry in pediatric keratoconus allows timely decisions in patient management. This research was carried out with the objective of describing the clinical characteristics and the treatment of three pediatric cases with different degree of interocular asymmetry of keratoconus, treated in the provincial consultation of pediatric corneal ectasia in Ciego de Avila. Patients showed difference between both eyes in clinical signs, refraction and topographic variables. Patient two was diagnosed with keratoconus in one eye, with no clinical or topographic evidence of the disease in the contralateral eye. All patients showed compound myopic astigmatism in both eyes and optical correction was indicated. Patient one was corrected with glasses, patient two with rigid gas permeable contact lenses and patient three with piggyback in one eye and rigid gas permeable contact lenses in the other eye. They also presented an associated amblyopia and were directed occlusive treatment and near vision tasks in patients two and three. It is common to find interocular asymmetry in pediatric patients with keratoconus due to the difference in progression between the two eyes. Periodic follow-up makes it possible to diagnose the disease in the contralateral eye in patients diagnosed with keratoconus in one eye, to indicate individualized optical correction, especially in the presence of anisometropia, and to monitor the evolution of frequently associated refractive amblyopia(AU)

Piggyback corneal como alternativa en el tratamiento del queratocono / Corneal Piggyback as an Alternative in the Treatment of Keratoconus

El queratocono es una afección inflamatoria, es una ectasia corneal que se caracteriza por un aumento de la curvatura corneal. Se describe como una enfermedad progresiva y asimétrica asociada con cambios estructurales en la organización del colágeno corneal. Existen diferentes opciones terapéuticas con el objetivo de estabilizar la superficie corneal, mejorar la visión y evitar su progresión. El sistema piggyback consiste en adaptar un lente rígido de gas permeable con alta permeabilidad al oxígeno sobre un lente de contacto hidrofílico, es ideal para pacientes que requieren la óptica de un lente de contacto rígido, pero tienen dificultades con su material. Se indica cuando existe una intolerancia a los lentes rígidos de gas permeable, en córneas irregulares y con curvaturas avanzadas. Se presenta una paciente de 24 años de edad con diagnóstico de queratocono desde los 10 años de edad que se corregía con lente rígido de gas permeable. Acudió a consulta del servicio de córnea del Instituto Cubano de Oftalmología Ramón Pando Ferrer, en el año 2010 porque comenzó a presentar intolerancia a los lentes. Debido a que la paciente no presentaba criterio quirúrgico y tenía una agudeza visual mejor corregida con lentes de 1,0 en ambos ojos, se decidió realizar el tratamiento con piggyback corneal. Pese al seguimiento, como parte de la progresión de la enfermedad, a los 10 años de mantenerse con el piggyback, presentó un hidrops corneal agudo, el cual fue tratado. En la actualidad la paciente mantiene seguimiento anual por consulta, sin progresión del queratocono y sin complicaciones con el tratamiento de piggyback corneal(AU)

Keratoconus is an inflammatory condition, a corneal ectasia characterized by increased corneal curvature. It is described as a progressive and asymmetric disease associated with structural changes in the organization of corneal collagen. There are different therapeutic options to stabilize the corneal surface, improve vision and prevent progression. The piggyback system consists of fitting a rigid gas permeable lens with high oxygen permeability over a hydrophilic contact lens, it is ideal for patients who require the optics of a rigid contact lens, but have difficulties with its material. It is indicated when there is intolerance to rigid gas permeable lenses, in irregular corneas and with advanced curvatures. We present a 24-year-old female patient with a diagnosis of keratoconus since she was 10 years old, which was corrected with a rigid gas permeable lens. She went to the cornea service of the Cuban Institute of Ophthalmology Ramón Pando Ferrer, in 2010 because she began to present intolerance to lenses. Since the patient did not present surgical criteria and had a visual acuity better corrected with 1.0 lenses in both eyes, it was decided to perform corneal piggyback treatment. Despite the follow-up, as part of the progression of the disease, after 10 years of piggyback, she presented an acute corneal hydrops, which was treated. At present, the patient maintains annual follow-up via consultation, without progression of keratoconus and without complications with the corneal piggyback treatment(AU)

Comparison of surgically induced astigmatic changes after cataract surgery in post-Laser in situ keratomileusis corneas versus virgin eyes / Comparação de alterações astigmáticas induzidas cirurgicamente após cirurgia de catarata em córneas ceratomileusis in situ pós-Laser versus olhos virgens

ABSTRACT Purpose: Postoperative refraction in modern mi­croincision cataract surgery gained extra importance in patients with the previous laser-assisted in situ keratomileusis (LASIK) surgery. The surgically induced astigmatic changes in those eyes may differ not only in magnitude but also in direction compared to virgin corneas. This study aimed to compare the surgically induced astigmatic changes after microscopic cataract surgery between post-LASIK corneas and virgin eyes. Methods: Cases that underwent microincision cataract surgery in eyes with and without previous LASIK surgery were reviewed. The demographics, the axial length at cataract surgery, the central corneal thickness, spheric and cylindric values, keratometry readings, and postoperative posterior corneal astigmatism were retrospectively evaluated. A modified Alpins method was used for astigmatic vector analysis, and baseline astigmatism, surgically induced astigmatism, difference vector, flattening effect, and torque were assessed. Results: A total of 42 eyes from 24 subjects was evaluated. Group I consisted of 14 eyes with the previous LASIK, and Group II included 28 eyes without any refractive surgery. Preoperative mean central corneal thickness in Group I was significantly thinner (p=0.012). There was no significant difference in baseline astigmatism between the groups regarding magnitude and power vectors. After microincision cataract surgery, there were no significant differences in mean spheric and cylindric values and mean keratometry readings (all p>0.05). However, surgically induced astigmatism and difference vector were significantly higher on J45 vector component in post-LASIK eyes and microincision cataract surgery steepening effect on post-LASIK corneas was significantly higher than those in virgin eyes (p=0.001, p=0.002 and p=0.018, respectively). Conclusions: Cataract surgery has steepened the corneas in both groups with a significantly higher steepening effect in post-LASIK eyes. Certainly, corneal topography cataract surgery is particularly helpful to provide more precise surgically induced astigmatism interpretations.

RESUMO Objetivo: A refração pós-operatória na cirurgia mo­derna de catarata por microincisão ganha ainda mais importância em pacientes com cirurgia prévia de ceratomileuse in situ assistida por laser (LASIK). As alterações astigmáticas induzidas cirurgicamente nesses olhos podem diferir não apenas em magnitude, mas também em direção em comparação com córneas virgens. O objetivo deste estudo foi comparar as alterações astigmáticas induzidas cirurgicamente após cirurgia de catarata por microincisão entre córneas pós-LASIK e olhos virgens. Métodos: Foi revisada uma série de casos de cirurgia de catarata por microincisão em olhos com e sem cirurgia LASIK anterior. Os dados demográficos, o comprimento axial no momento da cirurgia de catarata, a espessura central da córnea, os valores esféricos e cilíndricos, as leituras da ceratometria e o astigmatismo corneano posterior pós-operatório foram avaliados retrospectivamente. O método Alpins modificado foi usado para análise vetorial astigmática e foram avaliados o astigmatismo basal, o astigmatismo induzido cirurgicamente, o vetor de diferença, o efeito de achatamento e o torque. Resultados: Ao todo, 42 olhos de 24 indivíduos foram avaliados. O Grupo I consistiu em 14 olhos com LASIK prévio; o Grupo II incluiu 28 olhos sem qualquer cirurgia refrativa. A média da espessura corneana central pré-operatória no Grupo I foi significativamente mais fina (p=0,012). Não houve diferença significativa no astigmatismo basal entre os grupos em termos de magnitude e vetores de potência. Após a cirurgia de catarata por microincisão, não houve diferenças significativas nos valores médios esféricos, cilíndricos e leituras médias de ceratometria (todos com p>0,05). No entanto, o astigmatismo induzido cirurgicamente e o vetor de diferença foram significativamente maiores no componente do vetor J45 em olhos pós-LASIK, e o efeito de aumento da inclinação pela cirurgia de catarata por microincisão nas córneas pós-LASIK foi significativo em comparação com olhos virgens (p=0,001, p=0,002 e p=0,018, respectivamente). Conclusões: A cirurgia de catarata aumentou a inclinação das córneas em ambos os grupos, sendo esse aumento significativamente maior nos olhos pós-LASIK. Certamente, a topografia da córnea antes da cirurgia de catarata é particularmente útil para fornecer interpretações mais precisas do astigmatismo induzido cirurgicamente.

Comparação entre os resultados do implante de um segmento de arco longo versus dois segmentos de arco tradicional no tratamento de pacientes com ceratocone / Comparison between the results of implanting a long-arch segment versus two standard arch segments for treatment of keratoconus patients

RESUMO Objetivo: Analisar retrospectivamente as alterações na ceratometria e no astigmatismo corneano obtidas após cirurgia de implante de anel intraestromal, comparando o uso de um segmento de arco longo versus o implante de dois segmentos de comprimento de arco tradicional. Métodos: A partir de um estudo transversal, obtivemos os dados de 94 olhos de pacientes diagnosticados com ceratocone, que foram submetidos ao implante de anel corneano. Eles foram divididos em dois grupos, dependendo do tipo de implante recebido: Grupo A, um segmento de arco longo; Grupo B, dois segmentos tradicionais. Todos os segmentos implantados possuíam 250µ de espessura. Os dados do pré-operatório dos dois grupos foram comparados, para garantir que as amostras eram similares (as diferenças encontradas entre os dois grupos não eram estatisticamente significativas). As variáveis analisadas no pré e no pós-operatório foram acuidade visual com correção, ceratometria, astigmatismo corneano e refração. Resultados: A amostra que recebeu apenas um segmento de arco longo (Grupo A) obteve redução da ceratometria média de 4,42D (8,7%) e do astigmatismo corneano de 2,43D (40,4%). Já na amostra dos olhos que receberam dois segmentos de arco tradicional (Grupo B), houve redução média de 2,66D (5,1%) em relação à ceratometria média e redução média de 2,11D (34,8%) em relação ao astigmatismo corneano. A redução obtida na ceratometria média no Grupo A foi maior que a obtida no Grupo B (diferença estatisticamente significativa). A redução obtida no astigmatismo do Grupo A não foi estatisticamente significante, se comparada com o resultado obtido no Grupo B (considerando p≤0,05). Conclusão: Foi demonstrado que o uso de um segmento de arco longo possui maior capacidade de aplanação corneana, se comparado com o uso de dois segmentos com comprimento de arco tradicional. Em relação à redução do astigmatismo, os dois grupos mostraram resultados equivalentes.

ABSTRACT Purpose: To retrospectively analyze the changes in corneal keratometry and astigmatism after intrastromal ring surgery, comparing the use of one long arch segment versus two traditional arc length segments. Methods: A cross-sectional study obtained data from 94 eyes of patients diagnosed with keratoconus that underwent surgical treatment with corneal ring implant. They were divided into two groups according to the type of implant received: one long-arch segment (Group A) or two traditional segments (Group B), both 250 microns thick. Preoperative data from the two groups were compared to ensure that the samples were similar (the differences between the two groups were not statistically significant). The variables (pre and post-operatively) analyzed were: best corrected visual acuity, keratometry, corneal astigmatism and refraction. Results: Group A, which received one long arch segment, showed a Km decrease of 4.42D (8.7%) and a corneal astigmatism reduction of 2.43D (40.4%). Group B, where the eyes acquired two traditional arch segments, showed an average Km decrease of 2.66D (5.1%) and corneal astigmatism reduction of 2.11D (34.8%). The mean keratometry (Km) reduction obtained was statistically significant (p≤0.05) when comparing both groups (A and B). The mean corneal astigmatism reduction was not statistically significant (p≤0.05) when comparing both groups (A and B). Conclusions: One long-arch segment has been demonstrated to have a greater capacity to reduce corneal curvature when compared to the use of two traditional-sized arch segments. No significant differences were found regarding the reduction of corneal astigmatism after comparing the results obtained in both groups.

Mal posicionamiento de háptica como causa de sorpresa refractivaastigmática / Haptic Poor Positioning as a Cause of Astigmatic RefractiveSurprise

Un resultado refractivo no esperado luego de una cirugía de catarata puede tener múltiples causas, ya sean preoperatorias, operatorias y posoperatorias. Como las más importantes se han descrito los errores en el cálculo biométrico en el preoperatorio y también las menos probables o infrecuentes como: inadecuada selección del poder del LIO, ausencia de precisión en la manufactura de los LIOs, intervención quirúrgica en paciente equivocado o en el ojo equivocado y el uso de un lente de contacto blando al momento de la biometría. Presentamos el caso de un paciente operado de catarata por facoemulsificación con implante de lente intraocular (LIO) monofocal plegable en saco capsular, que a los 30 días posoperatorios presentó un astigmatismo total o refractivo de - 1.00 dioptrías (D) x 110° pero a los 90 días de la cirugía, regresó por disminución de la agudeza visual con un astigmatismo refractivo de -5.50 D x 165° que no se relacionaba con el astigmatismo corneal medido por queratometría y topografía (-0.94 D x 82°). El ojo tenía medios transparentes y sin reportes de complicaciones posoperatorias inmediatas y mediatas. En este caso encontramos un mecanismo de inclinación del LIO provocado por una háptica deficientemente desplegada al momento de la inserción del LIO que no se evidenció en el acto quirúrgico asociado a desplazamiento de este, ocasionado por la fibrosis y contracción pupilar manifestando un efecto astigmático de manera tardía. Esto fue corroborado por ecografía con ultrabiomicroscopía y reposición quirúrgica del LIO logrando solucionar el caso(AU)

An unexpected refractive outcome after cataract surgery may have multiple causes, whether preoperative, operative or postoperative. The most important ones have been described as errors in the preoperative biometric calculation and also the less probable or infrequent ones such as: inadequate selection of IOL power, lack of precision in the manufacture of IOLs, surgical intervention in the wrong patient or in the wrong eye and the use of a soft contact lens at the time of the biometry test. We present the case of a patient who underwent cataract surgery by phacoemulsification with a monofocal foldable intraocular lens (IOL) implantation in the capsular bag, who 30 days after the operation presented a total or refractive astigmatism of - 1.00 diopters (D) x 110°. Sometime later, 90 days after surgery, he returned due to decreased visual acuity with a refractive astigmatism of -5.50 D x 165° which was not related to the corneal astigmatism measured by keratometry and topography (-0.94 D x 82°). The eye had clear mediums and showed no reports of immediate and gradual postoperative complications. In this case we found a mechanism of IOL tilt caused by a poorly deployed haptic at the time of IOL insertion that was not evident at the time of surgery associated with IOL displacement caused by fibrosis and pupillary contraction, which generated a late astigmatic effect. This was corroborated by ultrasound with ultrabiomicroscopy and surgical repositioning of the IOL, which allowed the case to be solved(AU)

Errores refractarios en estudiantes de medicina en un hospital docente / Refractory errors in medical students in a Teaching Hospital

Los errores de refracción contribuyen como un gran problema de salud pública. Las crecientes tasas de prevalencia de la miopía han alcanzado los niveles de epidemia en varias áreas. Este estudio tuvo como objetivo determinar las tasas de prevalencia de errores de refracción en los estudiantes de medicina. Se realizó un estudio prospectivo en el Departamento de Oftalmología, durante un período de un año desde enero de 2020 hasta diciembre de 2020. Los estudiantes de medicina fueron seleccionados al azar, como un total de 250 sujetos. Todos se sometieron a un examen oftálmico. De 250 estudiantes, se documentaron 148 (59.2%) casos de RE. La mayoría de los casos comunes eran mujeres (89, 60.1%), mientras que los hombres eran (59, 39.9%). De estos, 98 estudiantes tienen miopía (66.2%), 42 casos tienen astigmatismo (28.4%) y 8 casos tienen hipermetropía (5.4%). La etapa tardía de las clases (sexto) tiene los casos RE más frecuentes. La miopía fue la RE predominante entre los estudiantes de medicina. La clase anticipada y la mujer son factores predisponentes.

Refractive errors are contributing as a major public health problem. The increasing prevalence rates of myopia have reaching to epidemic levels in several areas. This study was aimed to determine the prevalence rates of refractive errors in medical students. A prospective study was conducted in the Department of Ophthalmology, over a period of one year from Jan 2020 to Dec 2020. Medical students were randomly selected, as a total of 250 subjects. All were undergoing an ophthalmic examination. Of 250 students, 148(59.2%) cases of RE were documented. Most common cases were female (89, 60.1%), whereas male was (59, 39.9%). Of these, 98 students have myopia (66.2%), 42 cases have astigmatism (28.4%) and 8 cases have hypermetropia (5.4%). The late stage of classes (6th) has the most frequent RE cases. Myopia was the predominant RE among the medical students. Advance class and female are predisposing factors

Un estudio de prevalencia de error de refracción en niños entrecerrados (6-12 años) asistiendo al Hospital Dr. Aso-Eye Shahed / A study of Prevalence of Refractive Error in Squinted children (6-12 years) attending shahed Dr. Aso-Eye Hospital

Determinar la prevalencia del error de refracción (RE) como causa en los ojos en los niños en niños de esta edad (6-12 años) en la ciudad de Sulaimania. El estudio de tasa de prevalencia entre los pacientes que asisten al Shahed Dr. Aso Eye Hospital para el período del 1 de octubre de 2008 al 1 de junio de 2009. Un total de 116 niños (6-12 años) asisten al departamento de entrecerrares durante aproximadamente 8 meses. El estudio incluyó ambos sexos, eran niños de 55 años y niñas 61. Se sometieron a un examen ocular completo. Encontramos que (72) pacientes (62.02 %) tenían un error de refracción, incluyen: 33 pacientes (45.9 %) = hipermetropia (H); 22 pacientes (29.16%) = miopía [m]; 18 pacientes (24.3%) astigmatismo (AST.); 4 mixtos; 6 h-as. y 8 m-as. En conclusiones, la causa más frecuente del entrecerrar de la infancia a este ancho [6-12 años) es el error refractivo, mientras que las otras causas en su conjunto constituyen solo 1/3 de las causas, y el error de refracción más común es la hipermetropía

To determine the prevalence of refractive error (RE) as a cause in squinted in children in this aged (6-12 years) in Sulaimania city. The prevalence rate study among patient attending Shahed Dr. Aso eye hospital for the period from 1st October 2008 - 1st June 2009. A total of 116 children ( 6-12 years) attending squint department for about 8 months. The study included both sexes, were boys 55 and girls 61. Underwent full ocular examination. We found that (72) patients (62.02%) had refractive error, include: 33 patients (45.9 %) = Hypermetropia (H); 22 patients (29.16%) = Myopia [M]; 18 patients (24.3%) Astigmatism (Ast.); 4 mixed; 6 H-Ast. and 8 M-Ast. In conclusions, the most prevalent cause of childhood squint at this aged [6-12 years) is refractive error while the other causes as a whole constitute only 1/3 of the causes, and most common refractive error is hypermetropia

Development of an application for providing corneal topography reports based on artificial intelligence / Criação de aplicativo para confecção de laudos de topografia corneana baseado na inteligência artificial

ABSTRACT Purpose: To develop an application (TopEye) in the iOS platform for mobile devices to allow the capture and interpretation of color maps generated by corneal topographers using artificial intelligence. Methods: In the execution, follow-up, and assessment of the project, we used the Scrum methodology and interactive and incremental development process for the project management and agile software development. The ge nerated diagnostic pattern bank consists of 1,172 examples of corneal topography, divided into 275 spherical, 302 symmetrical, 295 asymmetrical, and 300 irregular patterns (keratoconus). For the development of the artificial intelligence of the application, network training was established with 240 images of each pattern type, with a total of 960 patterns (81.91%). The remaining 212 images (18.09%) were used to test the application and will be used for the results. The process is semi-automatic, so the topographic image is captured with a smartphone, the examiner performs the contour of the corneal relief manually, and then the neural network performs the diagnosis. Results: The application diagnosed 201 cases (94.81%) correctly. In 212 images, the algorithm missed the classification of 11 cases (5.19%). The major error that occurred was in distinguishing between symmetrical and asymmetrical classes. In keratoconus screening, the application reached 95.00% sensitivity and 98.68% specificity. Conclusion: The work resulted in obtaining an efficient application to capture topographic images using a smartphone camera and their interpretations through applied artificial intelligence.

RESUMO Objetivo: Desenvolver um aplicativo (TopEye) na plataforma iOS para dispositivos móveis que possibilite a captação e interpretação do mapa de cores gerados por qualquer topógrafo corneano através da inteligência artificial (IA). Metodos: A execução, acompanhamento e avaliação do projeto foi utilizada a metodologia Scrum, processo de desenvolvimento interativo e incremental para gerenciamento de projetos e desenvolvimento ágil de software. O banco de padrões de diagnóstico gerado consiste em 1172 exemplos, divididos em: 275 padrões esféricos, 302 regulares simétricos, 295 regulares assimétricos e 300 irregulares (ceratocone). Para o desenvolvimento da inteligência artificial do aplicativo, foi estabelecido o treinamento da rede com 240 imagens de cada tipo de padrão, totalizando 960 (81,91%) padrões. O restante das imagens, 212 (18,09%), foram utilizadas para testar o aplicativo e usadas para gerar os resultados. O processo é semiautomático, assim a captação da imagem topográfica é realizada com smartphone, o examinador realiza o contorno do relevo corneano manualmente para em seguida a rede neural realizar o diagnóstico. Resultados: O aplicativo diagnosticou 201 (94,81%) imagens corretamente. De um total de 212 imagens, o algoritmo errou a classificação de apenas 11 (5,19%). A principal ocorrência de erro foi na distinção das classes simétrica e assimétrica. No rastreio do ceratocone o aplicativo alcançou 95,00% de sensibilidade e 98,68% especificidade. Conclusão: O trabalho resultou na obtenção de um aplicativo eficiente na captura da imagem topográfica pela câmera do smartphone e na interpretação da mesma através da inteligência artificial aplicada.

Defectos refractivos en pacientes prematuros / Refractive defects in premature patients

El nacimiento prematuro favorece la aparición de alteraciones visuales donde los defectos refractivos altos prevalecen, pues se afecta el proceso de emetropización. La revisión tuvo como objetivo describir la miopía del prematuro como resultado de una alteración en el desarrollo del segmento anterior. La hipermetropía se observa de mayor cuantía en estos pacientes, así como el astigmatismo significativo. Entre los factores de mayor peso se encuentran, además de la prematuridad, el bajo peso al nacer, la presencia de retinopatía del prematuro y su tratamiento con láser. Las evaluaciones oftalmológicas sistemáticas permiten detectar y corregir a tiempo estas alteraciones y favorecen una función visual óptima con menor riesgo de ambliopía. Los artículos que se consultaron son fundamentalmente de los últimos cinco años, en idiomas español e inglés, disponibles en textos completos y resúmenes en algunas bases de datos como PubMed, Ebsco, Google Académico y Scielo(AU)

Preterm birth may affect the emmetropization process, leading to the appearance of visual alterations characterized by a high prevalence of refractive defects. A case is described of myopia of prematurity resulting from an alteration in the development of the anterior segment. Hyperopia and astigmatism are significantly frequent in these patients. Other causative factors besides prematurity are low birth weight, the presence of retinopathy of prematurity and its treatment with laser therapy. Systematic ophthalmologic evaluation allows early detection and correction of these alterations, leading to optimal visual function and a lower risk for amblyopia. The articles consulted are mainly from the last five years, written in Spanish or English, and available as full texts and abstracts in databases like PubMed, EBSCO, Google Scholar and SciELO(AU)

Uso de la topografía corneal en pacientes operados de pterigión para el mejoramiento del desempeño profesional / Use of the corneal topography for a better professional training in patients with pterigion surgery

Introducción: La operación de pterigión se exige como habilidad desde el primer año de residencia y la evaluación topográfica es clave para evaluar las modificaciones corneales y perfeccionar las habilidades clinicoquirúrgicas de los cirujanos en formación. Objetivo: Determinar las modificaciones corneales en pacientes operados de pterigión en el Centro Oftalmológico de Santiago de Cuba. Métodos: Se realizó un estudio descriptivo, prospectivo y transversal de 53 pacientes operados de pterigión en el Centro Oftalmológico de Santiago de Cuba, desde enero de 2019 hasta igual mes de 2021, a los cuales se les evaluó topográficamente antes y después de la intervención quirúrgica. Resultados: Predominaron el sexo femenino (60,4 %), el grupo etario de 40-49 años (5,8 %), el grado II de la enfermedad (43,4 %) y el astigmatismo inducido como complicación más frecuente (33,9 %). El poder corneal promedio sufrió variación de 43,25D a 45,75D y el astigmatismo topográfico descendió de 4,75 a 3,55 D. Conclusiones: Con el uso de la topografía se comprobó que existen modificaciones corneales importantes derivadas de la invasión del pterigión en la córnea y de la manipulación quirúrgica.

Introduction: Pterigium surgery is demanded as a skill in the first year of the residency and the topographical evaluation is a key element to evaluate corneal modifications and to improve clinical -surgical skill of training surgeons. Objective: To determine the corneal modifications in patients with pterigium surgery in the Ophthalmological Center from Santiago de Cuba, from January 2019 to the same month in 2021, in whom a topographical evaluation was carried out before and after the surgical procedure. Results: Female sex (60.4 %), age group 40-49 (5.8 %), the disease grade II (43.4 %) and induced astigmatism as the most frequent complication (33.9 %) predominated. Average corneal power suffered a variation of 43.25 D and 45.75 and the topographical astismatism decreased from 4.75 to 3.55 D. Conclusions: With the use of topography it was proven that there are corneal modifications derived from pterigium invasion to the cornea and from the surgical manipulation.

Characterization of ocular biometric parameters in Colombian candidates for cataract surgery / Caracterización de los parámetros biométricos oculares de pacientes colombianos candidatos a cirugía de catarata

Abstract Introduction: Intraocular lens (IOL) power calculation, based on ocular biometry, is a determinant for the success of cataract surgery. Objectives: To characterize the ocular biometric parameters of Colombian patients over 40 years of age who are candidates for cataract surgery and to determine the prevalence of the 9 clinical conditions proposed by Holladay according to the interaction between axial length (AL) and anterior chamber depth (ACD). Materials and methods: Analytical cross-sectional study. The ocular biometry results of 781 patients (831 eyes) who were going to be taken to cataract surgery between January 2014 and January 2015 in Medellín, Colombia, were reviewed. After applying exclusion criteria, 716 eyes were included for analysis. Data on age, sex, AL, keratometry (flat keratometry (K1) and steep keratometry (K2)), ACD and white-to-white distance were collected. Results are presented using descriptive statistics. Results: Most eyes were from women (62.3%). The mean values of AL, K1 and ACD were 23.37±1.51mm, 43.52±2.06 and 3.03mm±0.41, respectively. Mean AL in men was 23.62±1.37mm, and in women, 23.21±1.67mm. The highest mean AL was observed in patients <50 years old (23.84±2.41) and the lowest in patients ≥80 years old (22.96±1.03 mm). Regarding eye size according to their AL, 90.5% were normal, 4.89% long, and 4.61% short. Conclusions: 85% of the participants had normal biometric parameters. For the remaining 15%, it is necessary to take some precautions when calculating IOL power, such as using fourth-generation formulas like Holladay 2 in long eyes, because the same refractive behavior will not be obtained using traditional prediction formulas in these patients. Furthermore, according to the Holladay classification, excluding normal eyes, the most frequent eyes were those with myopia and axial hyperopia.

Resumen Introducción. El cálculo del poder del lente intraocular (LIO), basado en la biometría ocular, es un factor determinante del éxito en la cirugía de catarata. Objetivos. Caracterizar los parámetros biométricos oculares de pacientes colombianos mayores de 40 años candidatos a cirugía de catarata y determinar la prevalencia de las 9 condiciones clínicas propuestas por Holladay según la interacción entre longitud axial (LA) y profundidad de la cámara anterior (ACD). Materiales y métodos. Estudio transversal analítico. Se revisaron los resultados de biometría ocular de 781 pacientes (831 ojos) que iban a ser sometidos a cirugía de cataratas entre enero de 2014 y enero de 2015 en Medellín, Colombia. Luego de aplicar los criterios de exclusión, se incluyeron 716 ojos para análisis. Se recolectaron datos sobre edad, sexo, LA, queratometría (queratometría más plana (K1), queratometría más curva (K2)), ACD y distancia blanco-blanco. Los resultados se presentan mediante estadística descriptiva. Resultados. La mayoría de ojos eran de mujeres (62.3%). Las medias de LA, K1 y ACD fueron 23.37±1.51mm, 43.52±2.06 y 3.03±0.41mm, respectivamente. La media de LA en hombres fue 23.62±1.37mm, y en mujeres, 23.21±1.67mm. La media más alta de LA se observó en pacientes <50 años (23.84±2.41mm) y la más baja en aquellos ≥80 años (22.96±1.03mm). Respecto al tamaño de los ojos según su LA, 90.5% fueron normales; 4.89%, largos, y 4.61%, cortos. Conclusiones. 85% de los participantes tuvo parámetros biométricos normales. Para el 15% restante es necesario tomar precauciones al calcular el poder del LIO, tales como el uso de fórmulas de cuarta generación como la Holladay 2 en ojos largos, pues en estos pacientes no se obtendrá el mismo comportamiento refractivo con las fórmulas de predicción tradicionales. Además, según la clasificación de Holladay, excluyendo a los ojos normales, los ojos más frecuentes fueron aquellos con miopía e hipermetropía axial.

Control de la progresión del astigmatismo en la facoemulsificación / Control of the progression of astigmatism in phacoemulsification

Objetivo: Determinar cómo controlar la progresión del astigmatismo en la facoemulsificación para mejorar sus resultados. Métodos: Se realizó un estudio descriptivo, prospectivo, de serie de casos en 43 ojos de pacientes con diagnóstico de catarata, operados por la técnica de facoemulsificación por prechop con implante de lente intraocular plegable, en el Instituto Cubano de Oftalmología "Ramón Pando Ferrer" desde noviembre del año 2018 hasta abril de 2020. Se emplearon los porcentajes y números absolutos para las variables cualitativas, las cuantitativas, la media y la desviación estándar, con un intervalo de confianza del 95 por ciento. Resultados: La edad media fue de 69,4 ± 8,3 años (51,16 por ciento); la dureza NO3; la mejor agudeza visual sin corrección mejoró en el 76,75 por ciento entre 0,8 a 1,0; la queratometría media pre- vs. posoperatoria no mostró diferencias estadísticamente significativas; el cilindro refractivo posoperatorio fue menor de 0,5 dioptrías en el 72,09 por ciento; el 51,17 por ciento de los ojos en el preoperatorio tenían astigmatismo refractivo contra la regla, lo cual mejoró según esta al mes de operado en el 60,47 por ciento de los pacientes. La calidad de vida en el 100 por ciento de los casos fue muy buena al mes de operados, según FV-14. Conclusiones: La corrección del astigmatismo con las incisiones personalizadas en la facoemulsificación ofrece buena predictibilidad y mejora su calidad visual y de vida(AU)

Objective: Determine how to control the progression of astigmatism in phacoemulsification to improve its results. Methods: A descriptive prospective study was conducted of a case series of 43 eyes of cataract patients undergoing prechop phacoemulsification with foldable intraocular lens implantation at Ramón Pando Ferrer Cuban Institute of Ophthalmology from November 2018 to April 2020. Percentages and absolute numbers were used for qualitative variables, and mean and standard deviation for quantitative variables, with a confidence interval of 95 percent. Results: Mean age was 69.4 ± 8.3 years (51.16 percent); hardness was NO3; in 76.75 percent best uncorrected visual acuity improved 0.8-1.0; pre- vs. postoperative mean keratometry did not show any statistically significant differences; in 72.09 percent the postoperative refractive cylinder was smaller than 0.5 diopters; 51.17 percent of the eyes had preoperative refractive against-the-rule astigmatism, improving at one month postoperative in 60.47 percent. Quality of life by the VF-14 survey was very good in 100 percent of the patients one month after surgery. Conclusions: Correction of astigmatism with personalized incisions in phacoemulsification provides good predictability and improves visual quality and quality of life(AU)

Resultados refractivos del implante secundario de lente en la cámara anterior con apoyo angular y de lente suturado a iris / Refractive results of anterior chamber angle-supported and iris-suture-fixated secondary lens implantation

Objetivo: Comparar los resultados refractivos del implante secundario de lentes intraoculares rígidos de la cámara anterior con apoyo angular y de lentes intraoculares plegables de la cámara posterior suturados a iris. Métodos: Se realizó un estudio casi experimental con control no equivalente (cohorte histórica). Se estudiaron 50 pacientes (50 ojos) con afaquia e inadecuado soporte capsular después de la cirugía de catarata, a quienes se les realizó implante secundario de lente intraocular con dos técnicas diferentes: lente intraocular en la cámara anterior con apoyo angular (25 ojos) y lente intraocular plegable de la cámara posterior suturado a iris (25 ojos). Resultados: Se observó que en el grupo de pacientes tratados con lente intraocular suturado a iris el porcentaje de pacientes con una visión de 20/40 o más fue significativamente superior (96,0 por ciento vs. 60,0 por ciento, p= 0,000) en los resultados refractivos obtenidos según el grupo de tratamiento. En el grupo A predominaron los pacientes que quedaron emétropes, seguidos de los pacientes miopes. En el grupo B predominaron los pacientes miopes y a diferencia del grupo anterior ningún paciente quedó hipermétrope. Conclusiones: La lente intraocular plegable de la cámara posterior suturada a iris mostró ser más eficaz, indujo menos astigmatismo y fue mejor en la predictibilidad de la esfera en un rango estricto de ± 1,00 dioptrías(AU)

Objective: Compare the refractive results of secondary implantation of rigid angle-supported intraocular lenses in the anterior chamber and foldable iris-suture-fixated intraocular lenses in the posterior chamber. Methods: A quasi-experimental non-equivalent control (historical cohort) study was conducted of 50 patients (50 eyes) with aphakia and inadequate capsular support after cataract surgery, who underwent secondary intraocular lens implantation with two different techniques: angle-supported intraocular lens in the anterior chamber (25 eyes) and foldable iris-suture-fixated intraocular lens in the posterior chamber (25 eyes). Results: In the group treated with iris-suture-fixated intraocular lens implantation the percentage of patients with 20/40 vision or more was significantly higher (96.0 percent vs. 60.0 percent, p= 0.000) in the refractive results obtained for each treatment group. In Group A a predominance was found of emmetropic, followed by myopic patients. In Group B myopic patients prevailed and unlike the other group no patient was hyperopic. Conclusions: Foldable iris-suture-fixated posterior chamber intraocular lenses proved more effective, induced less astigmatism and displayed better sphere predictability in a strict range of ± 1.00 diopters(AU)

Influência da espessura dos segmentos de anel corneano na correção do astigmatismo ceratométrico em pacientes com ceratocone / Influence of corneal ring segment thickness on correction of corneal astigmatism in patients with keratoconus

RESUMO Objetivo: Avaliar retrospectivamente a influência da espessura do anel intracorneano na redução do astigmatismo corneano em pacientes portadores de ceratocone. Métodos: De um banco de dados com 2.033 olhos submetidos à cirurgia de implante de anel corneano, foi selecionada uma amostra de 90 olhos com características semelhantes em relação à ceratometria e ao astigmatismo. Todos os olhos deste estudo receberam dois segmentos de comprimento de arco tradicional de aproximadamente 160°, com espessuras variadas: Grupo A recebeu dois segmentos de 150µm; Grupo B recebeu dois segmentos de 200µm, e Grupo C recebeu dois segmentos de 250µm. As variáveis analisadas foram ceratometria média e astigmatismo corneano pré e pós-operatório. Resultados: Nos olhos que receberam dois segmentos de anel de 150µm de espessura (Grupo A), houve redução média de 5,0D (10%) em relação à ceratometria média e redução média de 3,26D (57,69%) em relação ao astigmatismo corneano. Na amostra em que foram utilizados dois segmentos de 200µm (Grupo B), foi observada redução da ceratometria média de 7,0D (14,28%) e do astigmatismo corneano de 3,53D (63,6%). Já na amostra que recebeu dois segmentos de anel de 250µm de espessura (Grupo C), a redução média da ceratometria foi de 10D (20,4%) e de seu astigmatismo corneano de 2,09D (38,99%). Conclusão: Nos pacientes com ceratocone submetidos à cirurgia de anel corneano, o aumento da espessura dos segmentos implantados promove maior aplanamento da córnea, mas não o aumento em sua capacidade de reduzir o astigmatismo ceratométrico. Seria interessante a análise de uma amostra maior de pacientes, aliada a cálculos vetoriais de astigmatismo, para comprovar os achados deste estudo.

ABSTRACT Objective: To retrospectively evaluate the influence of intracorneal ring thickness on reduction of corneal astigmatism in patients with keratoconus. Methods: From a database of 2,033 eyes submitted to corneal ring implant surgery, a sample of 90 eyes with similar keratometry and astigmatism characteristics was selected. All eyes in this study received two segments of traditional arc length of approximately 160°, with varying thicknesses: Group A received two segments of 150 µm; Group B received two segments of 200 µm, and Group C received two segments of 250 µm. The variables analyzed were mean keratometry and corneal astigmatism before and after surgery. Results: In the eyes that received two 150-µm ring segments (Group A), there was a mean reduction of 5.0 D (10%) in relation to mean keratometry, and a mean reduction of 3.26 D (57.69%) in relation to corneal astigmatism. In the sample in which two 200-µm segments (Group B) were used, there was a mean reduction in keratometry of 7.0 D (14.28%) and in corneal astigmatism of 3.53 D (63.6%). In the sample receiving two 250-µm ring segments (Group C), the mean reduction in keratometry was 10 D (20.4%) and in corneal astigmatism was 2.09 D (38.99%). Conclusion: In keratoconus patients undergoing corneal ring surgery, increased thickness of the implanted segments promotes greater flattening of the cornea, but does not enhance their ability to reduce corneal astigmatism. It would be interesting to analyze a larger sample of patients, combined with vector calculations of astigmatism, to confirm the findings of this study.

Parámetros biométricos oculares en candidatos a cirugía de catarata / Ocular biometric parameters in cataract surgery candidates

Introducción: Las estructuras ópticas pueden variar en su configuración y medida dependiendo de la edad, el sexo y la raza, por lo que su medición previa a la cirugía es un pilar fundamental para el cálculo correcto del lente intraocular. Caracterizar los rangos normales de estos parámetros en nuestra población suministra información importante que puede mejorar los resultados visuales tras la cirugía de catarata y alertar en aquellos casos que distan de la media de los rangos conocidos. Objetivo: Describir los parámetros biométricos oculares en pacientes candidatos a cirugía de catarata y analizar sus variaciones según la edad y el sexo. Método: Estudio observacional descriptivo, de corte transversal. Análisis retrospectivo de biometrías oculares realizadas con reflectometría óptica de baja coherencia en pacientes candidatos a cirugía de catarata. Resultados: Se evaluaron 820 ojos de 820 pacientes candidatos a cirugía de catarata, con una edad media de 68.1 ± 11.1 años, el 53.7% de sexo femenino. Los parámetros oculares promedios encontrados fueron: longitud axial (AL) 23.39 ± 1.11 mm, profundidad de cámara anterior (ACD) 3.37 ± 0.49 mm, astigmatismo corneal (AST) 1.09 ± 0.85 D, espesor corneal central (CCT) 529.43 ± 35.02 µm, poder queratométrico (K) 43.81 ± 1.64 D, queratometría plana 43.28 ± 1.69 D, queratometría curva 44.37 ± 1.74 D y distancia blanco a blanco 11.82 ± 0.52 mm. El promedio de AL y ACD fue mayor en los hombres que en las mujeres (p < 0.0001), y con el aumento de la edad el AST y el K mostraron una tendencia al incremento. Se encontró un 23.78% de astigmatismo con la regla, un 54.88% de astigmatismo contra la regla y un 21.34% de astigmatismo oblicuo. Conclusiones: El perfil de los datos biométricos evidenció diferencias significativas entre sexos y grupos de edad. Se encontró una buena correlación entre la AL, la ACD y la potencia corneal, y los promedios encontrados se corresponden bien con los de otras poblaciones de similar origen étnico.

Introduction: Optical structures can vary in their configuration and measurement depending on age, sex and race, so their measurement, prior to surgery, is a fundamental pillar for the correct calculation of the intraocular lens. Characterizing the normal ranges of these parameters in our population provides important information that can improve the visual results of cataract surgery and alert in those cases that are far from the mean of the known ranges. Objective: To describe the ocular biometric parameters in cataract surgery candidates. Method: Descriptive, cross-sectional study. Retrospective analysis of biometric parameters measured by optical low-coherence reflectometry in cataract surgery candidates. Results: The study evaluated 820 eyes of 820 cataract patients, the mean age was 68.1 ± 11.1 years, 53.7% female. Mean ocular parameters found were: axial length (AL) 23.39 ± 1.11 mm, anterior chamber depth (ACD) 3.37 ± 0.49 mm, corneal astigmatism (AST) 1.09 ± 0.85 D, central corneal thickness (CCT) 529.43 ± 35.02 µm, keratometry (K) 43.81 ± 1.64 D, flat keratometry (K1) 43.28 ± 1.69 D, steep keratometry (K2) 44.37 ± 1.74 D and white-to-white distance (WTW) 11.82 ± 0.52 mm. Mean AL and ACD were significantly longer in men (p < 0.0001) and with increasing age, AST and K showed an upward trend. 23.78% of astigmatism with the rule, 54.88% of astigmatism against the rule and 21.34% of oblique astigmatism were found. Conclusions: The profile of the biometric data showed significant differences between sex and age groups, a good correlation was found between axial length, chamber depth and keratometry. The averages found correspond well to those of other populations of similar ethnic origin