Hipertensión ocular asociada al desprendimiento de la retina regmatógeno / Ocular hypertension associated to rhegmatogenous retinal detachment

Objetivo: Describir el comportamiento de la hipertensión ocular asociada al desprendimiento de la retina regmatógeno. Métodos: Se realizó un estudio observacional descriptivo de corte longitudinal retrospectivo de una serie de casos atendidos en la consulta de Vítreo-Retina del Instituto Cubano de Oftalmología "Ramón Pando Ferrer" en el período comprendido de mayo del año 2016 a diciembre de 2019. Se estudiaron 7 ojos de 7 pacientes. Se utilizaron las siguientes variables: edad, sexo, antecedentes patológicos oculares, tiempo de evolución de la disminución de la visión, tensión ocular, tipo de rotura retinal, cirugía de retina realizada y tratamiento antihipertensivo ocular. Resultados: Predominó el sexo masculino, con un promedio de edad de 27,2 años. La mayoría de los pacientes tuvieron rotura retinal en el cuadrante nasal superior y todos en extrema periferia. Todos los pacientes tuvieron la presión intraocular antes de la cirugía por encima de 30 mmHg. A todos se le indicó tratamiento hipotensor tópico y se les realizó cirugía convencional. Con diferentes fluctuaciones de la presión intraocular posterior a la cirugía, todos los pacientes normalizaron la tensión ocular y mantuvieron la retina aplicada. Conclusiones: El diagnóstico correcto de este síndrome puede ofrecer dificultad porque los signos de una condición pueden enmascarar los de otra. El reconocimiento de la entidad puede ser más fácil si el oftalmólogo tiene en mente que estas entidades pueden aparecer juntas. De esta forma, se hace un diagnóstico y un tratamiento certero que evite la discapacidad visual por esta causa(AU)

Objective: Describe the behavior of ocular hypertension associated to rhegmatogenous retinal detachment. Methods: An observational retrospective longitudinal descriptive study was conducted of 7 eyes of 7 patients attending the Vitreous-Retina Service at Ramón Pando Ferrer Cuban Institute of Ophthalmology from May 2016 to December 2019. The variables considered were age, sex, ocular pathological antecedents, time of evolution of vision reduction, ocular tension, type of retinal tear, retinal surgery performed and ocular hypertension treatment. Results: A predominance was found of the male sex, with a mean age of 27.2 years. Most of the patients had retinal tear in the upper nasal quadrant, and all in the extreme periphery. In all cases, intraocular pressure was above 30 mmHg before surgery. All patients were indicated topical hypotensive treatment and underwent conventional surgery. With different intraocular pressure fluctuations after surgery, all patients normalized their ocular tension and retained the retina applied. Conclusions: Correct diagnosis of this syndrome may be difficult to achieve, since the signs of one condition may mask those of another. Identification may be easier if the ophthalmologist bears in mind that these diseases may occur together. An accurate diagnosis may thus be made and an effective treatment indicated which will prevent visual disability due to this cause(AU)

Fundamentos de agudeza visual aplicados en la construcción de estímulos visuales concéntricos. Estímulo Arorradial de Guerrero (EAG) / Fundaments of visual acuity applied to construction of concentric visual Stimuli. Guerrero´s Arorradial Stimulus (GAS)

Objetivo: comparar los parámetros fisiológicos y geométricos de los optotipos E de Snellen y C de Landolt, mediante cálculos y argumentos conceptuales, para formular el Estímulo Arorradial de Guerrero (EAG), basado en el principio angular de los primeros y la disposición concéntrica de Landolt. Metodología: se fundamentó en una revisión bibliográfica de la agudeza visual, fundamentos fisiológicos, cálculo geométrico-trigonométrico y principios anatómicos aplicables al diseño de estímulos. Dicho análisis reveló elementos comunes y diferencias del área impresa y el área perimetral de los estímulos comparados y permitió formular una matriz EAG con patrones homogéneos de estimulación foveolar. Resultados: se hallaron elementos comunes de configuración angular de los estímulos y diferencias en sus parámetros morfológicos, perimetrales y geométricos. Esto sugiere la confiabilidad de la matriz concéntrica, que estimula de forma coherente con la distribución anatómica de los fotorreceptores y, presumiblemente, brinda mayor confiabilidad de las respuestas visuales. Conclusiones: las diferencias perimetrales y geométricas halladas entre los estímulos alfanuméricos de una misma prueba sugieren que las pruebas concéntricas direccionales reúnen las condiciones de estimulación de áreas retinales homogéneas para favorecer respuestas basadas en discriminación óptica y no en legibilidad. El EAG podría constituirse en una alternativa modificada de los estímulos Landolt que, al incorporar elementos radiales que confieren direccionalidad al estímulo y distractores, permitirían estudiar cualitativamente el astigmatismo refractivo y la simulación.

Objective: To compare the physiological and geometrical parameters of the Snellen E and Landolt C optotypes, through calculations and conceptual arguments, to formulate the Guerrero’s Arorradial Stimulus (GAS), based on the angular principle of the former and Landolt’s concentric arrangement. Methodology: It was based on a literature review of visual acuity, physiological basis, geometric-trigonometric calculation and anatomical principles applicable to the design of stimuli. The analysis revealed common elements and differences of the printed area and the perimeter area of the compared stimuli and made it possible to formulate a EAG matrix with homogeneous patterns of foveolar stimulation. Results: Common elements of angular configuration of the stimuli and differences in their morphological perimeter and geometric parameters were found. This suggests the reliability of the concentric matrix, which stimulates in a manner consistent with the anatomical distribution of photoreceptors and presumably provides greater reliability of visual responses. Conclusions: Perimeter and geometric differences found between alphanumeric stimuli of the same trial suggest that directional concentric tests gather the conditions of stimulation of homogeneousretinal areas to promote answers based on optical discrimination rather than readability. The GAS could become a modified alternative of the Landolt stimuli, which, by including radial elements that confer directionality to the stimulus and distractors, make it possible to conduct a qualitative study of refractive astigmatism and simulation.

Trasplante de tejido retiniano y de células progenitoras retinianas: una promesa terapéutica para pacientes con enfermedad de la retina / Retinal tissue transplantation and retinal progenitor cells: a therapeutic promise for patients with retinal disease

La retinopatía diabética, la degeneración macular relacionada con la edad y la retinitis pigmentosason las enfermedades retinianas más frecuentes en todo el mundo. A pesar de no contar consuficientes estudios que demuestren resultados funcionales positivos en cuanto a recuperar lafunción visual, el uso de células madre y células progenitoras retinianas y el trasplante de retinafetal parecen bastante promisorios. Hasta el momento no se han podido obtener resultadospositivos sobre la funcionalidad de las células trasplantadas, pero sí se ha demostrado que elprocedimiento para transferir el tejido retiniano es seguro y confiable. Aún no se ha intentadoen seres humanos el trasplante de células progenitoras retinianas, pero dicho trasplante ha dadoresultados satisfactorios en modelos múridos. Los estudios con células progenitoras retinianashan logrado demostrar en modelos múridos que se activan y expresan los fotorreceptores. Existenalgunas barreras de disponibilidad para el uso de células progenitoras retinianas, que se debensuperar con el fin de adelantar estudios que permitan aumentar las posibilidades de integracióny diferenciación de dichas células hacia fotorreceptores.

Retinal tissue transplantation and retinal progenitor cells: A therapeutic promise for patients with retinal diseaseWorldwide, diabetic retinopathy, age-related macular degeneration, and retinitis pigmentosahave the highest incidence rate among retinal diseases. Despite the lack of enough trialsdemonstrating positive functional results on eyesight recovery, the use of stem cells, retinalprogenitor cells, and fetal retinal tissue transplantation seem very promising. So far positiveresults on the functionality of the transplanted cells have not been obtained. However, the safetyand reliability of the procedure to transfer retinal tissue have been demonstrated. Transplantationof retinal progenitor cells has not been tried on human beings, but there have been satisfactory results with it in murine models. Trials with retinalprogenitor cells have demonstrated activation andexpression of photoreceptors in murine models. Somebarriers of availability exist for the use of retinalprogenitor cells that must be overcome in order tocarry out studies to increase the possibility of theirintegration and differentiation towards photoreceptors.

Estudo experimental da aplicação retiniana do laser infravermelho via transescleral sob condições de baixa visibilidade / Transscleral infrared laser retinal photocoagulation experimental study under low visibility conditions

OBJETIVOS: Pesquisa experimental, com laser de diodo infravermelho, para estimar a segurança, a reprodutibilidade e a permeabilidade da parede ocular à sua atuação clínica, quando aplicado via transescleral, em condições de baixa visibilidade. MÉTODOS: Submetemos olhos de coelhos pigmentados da raça Nova Zelândia à fotocoagulação retiniana por laser de diodo infravermelho. No olho direito, realizamos fotocoagulação via transescleral sob parâmetros de potência e tempo pré-determinados clinicamente. No olho esquerdo, foram repetidos os mesmos valores da potência e tempo usados no olho direito, desta vez, via transpupilar. Imediatamente e após 2 meses, estudos clínicos baseados na retinografia e histopatológicos foram realizados. RESULTADOS: A permeabilidade da parede ocular, quando da aplicação do laser de diodo infravermelho via transescleral, variou entre 58,95 e 63,87 por cento. A média da permeabilidade da parede ocular a 300 mW (63,14 por cento) mostrou-se significativamente superior àquela da permeabilidade da parede ocular encontrada a 500 mW (59,11 por cento), (P<0,05). CONCLUSÕES: Este estudo sugere a existência da relação dose-resposta em relação aos parâmetros empregados na aplicação do laser de diodo infravermelho via transescleral, com permeabilidade da parede ocular mensurável e reprodutível. Nenhuma rotura, hemorragia ou descolamento da retina ou vítreo foi constatado aos exames subseqüentes às aplicações do laser de diodo infravermelho, o que torna o uso da fotocoagulação via transescleral, no modelo experimental, seguro, mesmo sob condições de baixa visibilidade dos meios.

PURPOSE: Retinal photocoagulation under poor visualization condition is often required. Transscleral infrared laser can be used as an alternative to regular transpupillary treatment. Based upon retinographic measurements, we proposed to estimate the reproducibility as well as ocular wall permeability rate for this treatment. Our primary goal was to evaluate whether this technique can deliver adequate photocoagulation at predetermined parameters without direct retinal visualization. METHODS: In New Zealand pigmented rabbits, optimal transscleral infrared diode laser settings were administered to the right eye. With the same parameters, transpupillary photocoagulation was repeated in the left eye. Retinographic and clinical examinations were performed immediately and two months later. RESULTS: Ocular wall permeability rate varied between 58.95 and 63.87 percent. Average permeability using a power of 300 mW (63.14 percent) was found to be higher than that encountered before its enhancement up to 500 mW (59.11 percent), (P<0.05). CONCLUSIONS: Setting parameters showed dose-response effect. No retinal hole or retinal detachment was noticed in any rabbit. Transscleral infrared photocoagulation appeared to be a reproducible and secure method in the experimental model.

Estudo do buraco macular fechado cirurgicamente: avaliação da relação entre a integridade da camada de fotorreceptores e a acuidade visual final por meio da tomografia de coerência óptica / Optical coherence tomography evaluation of surgically closed macular holes: photoreceptor layer analysis and its correlation with final visual outcome

O objetivo deste estudo foi correlacionar a integridade da camada dos fotorreceptores da retina com a visão final obtida em pacientes operados de buraco macular idiopático. Foram colhidas imagens tomográficas da região foveal de 39 olhos de 37 pacientes operados com sucesso a mais de um ano. Dados adicionais pré-operatórios como o tamanho do buraco, tempo de duração da doença e acuidade visual inicial também foram obtidos. Os olhos foram divididos em três grupos por ordem crescente de integridade da camada dos fotorreceptores. Os olhos pertencentes ao grupo de maior integridade apresentaram acuidade visual final significativamente superior aos alocados no grupo de menor integridade. As características iniciais dos buracos não se relacionaram com o resultado visual final. Concluiu-se que uma maior integridade da camada de fotorreceptores exerce papel importante na recuperação da visão em pacientes operados de buraco macular...

The objective of this study was to correlate the integrity of the retinal photoreceptor layer with final visual acuity in successfully operated macular hole patients. Using optical coherence tomography, foveal images were obtained from 39 eyes of 37 patients. Additionally, lesion pre-operative data was collected involving initial visual acuity, lesion size and time duration of the symptoms. All eyes were then included in one of three groups according to their photoreceptor integrity. Optical coherence tomography data obtained shown that those eyes included in the group with better integrity presented superior visual acuity when compared to the other groups. The results were statistically significant. Baseline lesion characteristics did not correlate with a better outcome. In conclusion, post-operative integrity of the photoreceptor layer plays an important role in achieving good visual recovery in macular hole surgery...

Ultraestructura de la retinopatía causada por la hiperoxia en ratas en desarrollo / Ultra structure of retinopathy induced by hyperoxia in developing rats

In order to evaluate the effect of postnatal hyperoxia on retinal structure, newborn rats were exposed to different oxygenation intervals (80 ± 1%) with three interruptions of 21% (30 min each). Four groups of rats were exposed from birth to the 6th, 9th, 12th and 14th postnatal day, respectively and another group was placed under normoxia. After this period all oxygenated groups and the controls remained under normoxia until they were 30 days old for the structural analysis of retina. Retinal histology was carried out using conventional techniques for transmission electron microscopy (TEM). In the ganglion cell layer of the retina from rats exposed for 9 days to hyperoxia, capillaries with large projections toward the lumen, were observed as a possible consequence of cellular edema of endothelium. The most severe damage was observed in rats exposed to hyperoxia during 12 and 14 days, showing mitochondrias swollen up and without crests in the areas surrounding the capillaries, necrosis and apoptosis processes, dense bodies, cells with swollen cytoplasms and rupture of the plasmatic membrane. The results suggest that postnatal hyperoxia causes severe damages to the retina in developing rats with a direct relationship between the time exposed to oxygen and ultra structural damages.

Con el propósito de evaluar el efecto de la hiperoxia posnatal sobre la estructura retiniana se analizaron retinas de ratas recién nacidas expuestas a diferentes periodos de oxigenación (80 ±1%), con tres interrupciones de 21% (30 min c/u). Cuatro grupos de ratas fueron expuestas desde su nacimiento hasta el 6to, 9no, 12mo y 14to días de vida y otro grupo fue mantenido en normoxia. Después de este periodo tanto los grupos expuestos a la hiperoxia como los controles permanecieron en normoxia hasta una edad de 30 días para el análisis estructural de la retina. La histología se hizo usando técnicas convencionales para microscopía electrónica de transmisión (MET). En la capa de células ganglionares de la retina de ratas expuestas a nueve días de hiperoxia, se observaron capilares con notables proyecciones hacia la luz, posiblemente como consecuencia de edema celular del endotelio. El daño más intenso fue observado en las ratas expuestas a hiperoxia durante 12 y 14 días, mostrando mitocondrias hinchadas y sin crestas en las áreas circundantes a los capilares, procesos de necrosis y apoptosis, cuerpos densos, células con citoplasmas hinchados y con ruptura de la membrana plasmática. Los resultados sugieren que la hiperoxia posnatal causa graves daños a la retina en las ratas en desarrollo, con una relación directa entre el tiempo de exposición al oxígeno y los daños ultraestructurales.