Unexpectedly high corneal flap thickness and ectasia after mechanical LASIK / Espessura inesperadamente alta do flap corneano e ectasia após LASIK mecânico

ABSTRACT LASIK is a refractive surgical procedure in which a corneal flap is created to expose the corneal stromal bed. Preoperative estimation of corneal flap thickness is necessary to calculate the percentage tissue altered in LASIK, an important quantitative risk factor for ectasia. The objective of this study was to assess flap thickness and calculate percentage tissue altered to check if unexpectedly thicker flaps and higher percentage tissue altered could pose as risk factors of ectasia. Four subjects (eight eyes) were submitted to mechanical LASIK in 2009 and 2010. Pre and postoperative clinical and tomographic data were reviewed. Mean preoperative estimated percentage tissue altered was 39.18±1.31%, which was borderline for increased ectasia risk when considering the limit of 40%. However, when considering the postoperatively measured flap thickness, the actual mean percentage tissue altered turned out to be 45.17 ± 4.13%, which was significantly higher than predicted preoperatively (p=0.002). Unexpectedly higher postoperative percentage tissue altered may be responsible for corneal ectasia after mechanical LASIK.

RESUMO A LASIK é um procedimento cirúrgico refrativo, no qual um retalho corneano é criado para expor o leito estromal corneano. A estimativa pré-operatória da espessura do retalho corneano é necessária para calcular o percentual de tecido alterado no LASIK, um importante fator de risco quantitativo para ectasia. O objetivo deste estudo foi avaliar a espessura do retalho e calcular o percentual de tecido alterado para verificar se retalhos inesperadamente mais espessos e percentuais de tecido alterado mais altos poderiam representar fatores de risco de ectasia. Quatro indivíduos (oito olhos) foram submetidos à LASIK mecânica em 2009 e 2010. Dados clínicos e tomográficos pré e pós-operatórios foram revisados. A média de percentual de tecido alterado pré-operatória estimada foi de 39,18±1,31%, limítrofe para risco aumentado de ectasia quando considerado o limite de 40%. No entanto, ao considerar a espessura do retalho medida no pós-operatório, o percentual de tecido alterado médio real foi de 45,17±4,13%, ou seja, significativamente maior do que o previsto no pré-operatório (p=0,002). O percentual de tecido alterado pós-operatóriao inesperadamente mais alto pode ser responsável pela ectasia da córnea após LASIK mecânico.

Exérese de pterígio em paciente pós-LASIK com técnica de air bubble / Pterygium surgery with air bubble technique in a post-LASIK patient

RESUMO O pterígio é uma das doenças que mais acomete a superfície ocular, principalmente em regiões próximas ao Equador. Ocorre principalmente em adultos jovens, podendo ocasionar sintomas, danos estéticos e ópticos. Relata-se um caso de exérese de pterígio classificado pela extensão corneana em grau II e, pela vascularização, em grau 2 de Tan, com cirurgia prévia de LASIK, a partir de uma nova técnica, a técnica de Moscovici, a qual fundamenta-se na dissecção com bolha de ar, com a finalidade de separar o epitélio conjuntival do estroma profundo e da Tenon, com maior facilidade e rapidez e para obter enxertos finos.

ABSTRACT Pterygium is one of the diseases that most affect the ocular surface, especially in regions close to the equator. It mainly affects young adults and can cause symptoms, as well as aesthetic and optical impairment. We report a case of pterygium excision classified by grade II corneal extension and Tan grade 2 vascularization with previous laser in situ keratomileusis (LASIK) surgery, using a new technique, the Moscovici technique, which is based on dissection with an air bubble to separate easier and faster the conjunctival epithelium from the deep stroma and the Tenon, obtaining thinner grafts.

Treatment strategy for bilateral severe subepithelial fibrosis after photorefractive keratectomy enhancement / Estratégia de tratamento para fibrose subepitelial grave bilateral após aprimoramento com ceratectomia fotorrefrativa

ABSTRACT A 27-year-old healthy man with a history of bilateral photorefractive keratectomy (PRK) enhancement after femtosecond laser in situ keratomileusis (LASIK) presented with decreased uncorrected distance visual acuity (UDVA) of 20/125 in the right eye (OD) and 20/300 in the left eye (OS) six months after PRK. Examination revealed bilateral dense subepithelial opacities. Both eyes (OU) were treated with superficial keratectomy combined with phototherapeutic keratectomy (PTK) and adjunctive application of mitomycin C 0.02%. At three months follow up UDVA was 20/30 OD and 20/25 OS. Superficial keratectomy combined with PTK seems to be a safe and efficient technique for treatment of dense subepithelial scar formation following PRK enhancement after LASIK.

RESUMO Um homem saudável de 27 anos de idade com história de aprimoramento com ceratectomia fotorrefrativa (PRK) bilateral, após Ceratomileuse Assistida por Excimer Laser In Situ (LASIK) com laser de femtossegundos, apresentou diminuição da acuidade visual à distância não corrigida (AVNC) de 20/125 no olho direito (OD) e 20/300 no olho esquerdo (OE) seis meses após PRK. O exame revelou opacidades subepiteliais densas bilaterais. Ambos os olhos (AO) foram tratados com queratectomia superficial combinada com ceratectomia fototerapêutica (PTK) e aplicação adjuvante de mitomicina C a 0,02%. Aos três meses de acompanhamento, o AVNC foi de 20/30 OD e 20/25 OE. A ceratectomia superficial combinada com PTK parece ser uma técnica segura e eficiente para o tratamento da formação densa de cicatrizes subepiteliais após o aprimoramento com PRK pós-LASIK.

Laser topoguiado como tratamento de ectasia pós lasik / Topoguided laser as treatment of ectasia after lasik

RESUMO O laser in situ keratomileusis (LASIK) é o método cirúrgico refrativo mais realizado no mundo com excelentes resultados, porém tal método não é isento de riscos. A ectasia pós LASIK é uma complicação grave e se caracteriza por um aumento progressivo da curvatura e afinamento da córnea, resultando em astigmatismo irregular e diminuição da acuidade visual. Sua incidência na literatura atual é de aproximadamente 0,033%. O principal tratamento dessa complicação é o implante de anel intra-estromal com cross-linking. Neste artigo descrevemos um caso de uma mulher de 45 anos submetida a sucessivas tentativas de tratamento de ectasia pós LASIK, com implante de anel intra-estromal bilateral, sem sucesso em um dos olhos. Foi feito o uso do excimer laser topoguiado através do photorefractive keratectomy (PRK) sem o cross-linking, que optamos por não realizar pela estabilidade há anos, pelo risco alto de haze e pela ablação apenas na lamela (que era espessa).A paciente obteve melhorasignificativa da visão e da qualidade de vida. Mantemos o acompanhamento a cada seis meses desde então com a tomografia da córnea.

ABSTRACT The laser in situ keratomileusis (LASIK) is the most widely used refractory surgical method in the world with excellent results, but this method is not without risks. Post-LASIK ectasia is a serious complication and is characterized by a progressive increase in curvature and thinning of the cornea, resulting in irregular astigmatism and decreasing visual acuity. Its incidence in the current literature is approximately 0.033%. The main treatment for this complication is the implantation of an intra-stromal ring with crosslinking. In this article, we describe a case of a 45-year-old woman who underwent successive attempts to treat post-LASIK ectasia, with bilateral intra-stromal ring implantation, with no success in the eyes. Excimer laser was used, made through photorefractive keratectomy (PRK) without cross-linking and the patient obtained significant improvement in vision and in quality of life.

Tratamento de crescimento epitelial persistente pós-Lasik com debridamento mecânico, uso de álcool a 20% e cola de fibrina / Treatment of persistent epithelial ingrowth after Lasik with mechanical debridement, use of 20% alcohol and fibrin glue

RESUMO O Lasik é a técnica de cirurgia refrativa mais utilizada no mundo. Apesar de segura e efetiva, ela pode levar a algumas complicações. O crescimento epitelial pós-Lasik é uma complicação pós-operatória incomum, com prevalência maior em casos de retratamento. Geralmente, é um achado não progressivo e assintomático, que não requer tratamento, mas, em uma minoria de pacientes, os sintomas podem ser clinicamente significantes e variados. O tratamento é feito com debridamento mecânico do crescimento epitelial, mas alguns recursos adjuvantes também podem ser utilizados. O presente estudo consiste em um relato de caso de paciente com crescimento epitelial pós-Lasik que apresentou quatro recidivas após intervenções de debridamento epitelial, sutura de lamela corneana e ablação a laser. No quinto procedimento, o paciente foi finalmente tratado com combinação de debridamento epitelial, uso de álcool a 20% e cola de fibrina. Entretanto, a regressão do crescimento epitelial e a melhora da acuidade visual só ocorreram ao longo dos meses após a intervenção, o que mostra a importância de esperar um tempo para que ocorra a melhora da visão no pós-operatório, evitando-se reintervenções.

ABSTRACT Lasik is the most often performed laser refractive surgery worldwide. Despite its efficacy and safety, some complications may occur. Epithelial ingrowth is a rare postoperative complication of Lasik, with an increased prevalence in cases of retreatment. Epithelial ingrowth is usually a nonprogressive and asymptomatic finding, which requires no treatment; however, in a minority of cases, symptoms may be clinically significant and diverse. Treatment is done with mechanical debridement of the affected interface, and additional interventions may be required. This study reported a case of recalcitrant epithelial ingrowth after Lasik, whichrelapsed four times after mechanical debridement, flap lift and laser ablation. In the fifth intervention, the patient was finally treated with a combined scraping/use of 20% alcohol and fibrin glue. However, regression of epithelial ingrowth and better visual acuity were only observed some months after the intervention, which shows the importance of waiting for better vision in the postoperative period, thus avoiding new reinterventions.

Changes of angle Kappa and corneal morphology changes in myopic patients after Sub / 中南大学学报(医学版)

OBJECTIVES@#To investigate angle Kappa and diopter distribution in myopic patients and the changes of angle Kappa and corneal morphology after Sub-Bowman-Keratomileusis (SBK), and to analyze the effects of the surgery on corneal morphologic changes and the patients' near fixation characteristics.@*METHODS@#The clinical data of 134 myopic patients (268 eyes) undergoing SBK from August 2015 to August 2016 were retrospectively analyzed. Angle Kappa, corneal curvature in the central corneal region of 3 mm, and post-corneal Diff value were measured by Orbscan IIz Corneal Topography System before operation, 1 month and 6 months after operation. According to the values of angle Kappa before SBK, the patients were divided into 2 groups: the large K group (angle Kappa≥5°, 71 eyes) and the small K group (angle Kappa<5°, 197 eyes). Correlation analysis of the factors influencing angle Kappa at 6 months after operation was performed.@*RESULTS@#In the large K group, angle Kappa was (5.67±0.65)°, spherical equivalent was (-4.84±2.32) D, and angle Kappa was decreased after operation (both @*CONCLUSIONS@#The angle Kappa is decreased in low-moderate myopia patients with large angle Kappa, while is increased in high myopia patients with small angle Kappa after SBK. Myopia patients after SBK will look for the new balance of the binocular accommodation and vergence function for improving the comfort in the near-work situations.

Corneal suture for acute corneal hydrops secondary to post-LASIK ectasia: a case report / Sutura corneana em hidrópsia aguda secundária à ectasia pós LASIK: relato de caso

ABSTRACT Corneal ectasia is one of the main complications of keratorefractive procedures. In this report, we describe a case of corneal ectasia after laser-assisted in situ keratomileusis), which progressed with acute hydrops and aqueous leakage and required a suture for correction.

RESUMO A ectasia corneana é uma das principais complicações das cirurgias refrativas. Neste caso, descrevemos um caso de ectasia corneana induzida por laser-assisted in situ keratomileusis, que evoluiu com hidrópsia aguda e extravasamento de humor aquoso, necessitando de sutura corneana.

Satisfação de pacientes submetidos à cirurgia refrativa de PresbiLASIK / Satisfaction of patients submitted to PresbyLASIK refractive surgery

Resumo Objetivos: Avaliar a satisfação dos pacientes submetidos à cirurgia de Presbilasik central e determinar a prevalência de sintomas relatados após a cirurgia. Métodos: Este é um estudo descritivo, observacional, transversal, com dados obtidos de pacientes submetidos previamente ao PresbiLASIK. Resultados: A amostra consistiu de 45 pacientes, com média de idade de 57,7 (±7,19) anos. A nota média atribuída para a satisfação visual com o procedimento foi 8.9 (±1.0). A qualidade visual após a cirurgia foi classificada como igual ou melhor que a esperada por 84,5% dos pacientes e 31% apresentaram sintomas noturnos, como halos e raios de cometa. Conclusão: A qualidade de visão após o procedimento de PresbiLASIK foi altamente satisfatória para os pacientes. Fator determinante dessa satisfação é o processo de manejo das expectativas pré-operatórias dos pacientes, informando das possibilidades terapêuticas disponíveis, e, no caso da escolha cirúrgica, acerca das vantagens e limitações.

Abstract Objectives: Toassess the satisfaction of patients undergoing central Presbilasik surgery and to determine the age of patients who undergo PresbiLASIK and the prevalence of symptoms reported after surgery. Methods: This is a descriptive, observational, cross-sectional study with data collected from patients previously submitted to PresbiLASIK. Results: The sample consisted of 45 patients, with a mean age of 57.7 (±7,19) years. The average score attributed to visual satisfaction with the procedure was 8.9 (±1.0). Visual quality after surgery was classified as equal to or better than expected by 84.5% of the patients and 31% complained of nocturnal symptoms such as halos and comet rays. Conclusion: The quality of vision after the PresbiLASIK procedure was highly satisfactory for the patients. A determining factor for this satisfaction is the process of managing patients' preoperative expectations, informing them about the therapeutic possibilities available, and, in the case of surgical choice, about its advantages and limitations.

Post-laser in situ keratomileusis interface Arthrographis kalrae keratitis / Interface de pós-laser ceratomileuse in situ Arthographis Kalrae ceratite

ABSTRACT We describe a case of keratomycosis caused by Arthographis kalrae after excimer laser keratomileusis. A 38-year-old female developed stromal keratitis eight weeks after refractive surgery. She developed severe corneal stromal infiltration and mild anterior segment inflammation, which could not be treated with topical voriconazole 1%, but topical natamycin 5% ameliorated her condition. A reactivation of keratomycosis symptoms was observed; therefore, longer treatment was administered to the patient. It has been reported that A. kalrae keratomycosis is associated with exposure to soil and contact lens usage. However, the patient, who lived in a rural location, was neither involved in gardening activities nor had a history of wearing contact lenses. This is the first case of post-refractive A. kalrae keratomycosis.

RESUMO Descrevemos um caso de ceratomicose por Arthographis kalrae após ceratomileusis por excimer laser. Uma mulher de 38 anos desenvolveu ceratite estromal oito semanas após a cirurgia refrativa. Ela desenvolveu infiltração estromal grave da córnea e uma leve inflamação do segmento anterior, que não pode ser tratada com voriconazol tópico a 1%, mas a natamicina tópica a 5% melhorou sua condição. Uma reativação dos síntomas de ceratomicose foi observada; portanto, tratamento mais prolongado foi administrado a paciente. Tem sido relatado que a ceratomicose por A. kalrae está associada à exposição ao solo e ao uso de lentes de contato. No entanto, a paciente, que vivía em um local rural, não estava envolvida em atividades de jardinagem e nem tinha histórico de uso de lentes de contato. Este é o primeiro caso de ceratomicose pós-refrativa por A. kalrae.

Centration in refractive surgery / Centralização em cirurgia refrativa

ABSTRACT The point of centration for refractive surgery is a theme of great importance that generates considerable discussion among specialists and surgeons in the field. Notably, any changes in light can alter the size of the pupil, and the visual axis of the fixation line to the fovea is unique in each patient. A variety of options have been described in the literature with respect to centration in refractive surgery, and the results differ among these methods. No consensus has been established regarding the ideal refractive surgery technique for evaluation of centration in each patient that will yield a satisfactory surgical result.

RESUMO O ponto de centralização da cirurgia refrativa é tema de grande importância e gera muita discussão entre especialistas e cirurgiões da área. Afinal, qualquer alteração na luz pode alterar o tamanho da pupila, além disso, o eixo visual da linha de fixação para a fóvea é particular em cada paciente. Existem opções para centralização em cirurgia refrativa com resultados diferentes na literatura. Ainda não há consenso sobre a melhor técnica em cirurgia refrativa que avalie cada caso específico visando um resultado cirúrgico final satisfatório.

Finite element analysis of determining corneal biomechanical properties in vivo based on Corvis ST / 生物医学工程学杂志

The decrease of corneal stiffness is the key factor leading to keratoconus, and the corneal collagen fiber stiffness and fiber dispersion are closely related to the corneal biomechanical properties. In this paper, a finite element model of human cornea based on corneal microstructure, namely collagen fiber, was established before and after laser assisted in situ keratomileusis (LASIK). By simulating the Corvis ST process and comparing with the actual clinical results, the hyperelastic constitutive parameters and corneal collagen fiber stiffness modulus of the corneal material were determined before and after refractive surgery. After LASIK, the corneal collagen fiber stiffness modulus increased significantly, and was highly correlated with central corneal thickness (CCT). The predictive relationship between the corneal collagen fiber stiffness modulus and the corresponding CCT before and after surgery was: = exp(9.14 - 0.009CCT ), = exp(8.82 - 0.008CCT ). According to the results of this study, the central corneal thickness of the patient can be used to estimate the preoperative and postoperative collagen fiber stiffness modulus, and then a personalized corneal model that is more consistent with the actual situation of the patient can be established, providing a theoretical reference for more accurately predicting the safe surgical cutting amount of the cornea.

Comparison of Intraocular Lens Calculation Formulas for Phacoemulsification after corneal refractive surgery in asian eyes

@#OBJECTIVE: To compare the different intraocular lens (IOL) calculation formulas available on the American Society of Cataract and Refractive Surgery (ASCRS) IOL power calculator website among Asian eyes with previous corneal refractive surgery. METHODS: A retrospective cohort study of 84 eyes in 68 Asian patients who had phacoemulsification with previous LASIK or photorefractive keratectomy (PRK) was done. Using the post-phacoemulsification manifest refraction spherical equivalent (MRSE) as target refraction, IOL prediction error (PE) for each formula was calculated as the implanted minus the predicted IOL power. Refractive PE was determined by calculating that 1 diopter (D) of IOL PE produces 0.7 D of refractive error at the spectacle plane. RESULTS: Comparing the Shammas, Haigis-L, Barrett True-K No History, ASCRS Average IOL Power No History, Barrett True-K, and ASCRS Average IOL Power with Change in Manifest Refraction (ΔMR), the mean IOL PEs ranged from -0.23 to -0.62 D, with the Barrett True-K having the lowest PE. The median refractive PEs for all formulas were similar at 0.35 D, except for the Haigis-L at 0.53 D. The ASCRS average with ΔMR had a statistically higher percentage of eyes within 0.5 D of target refraction versus other formulas (p<0.05). The Haigis-L IOL PE and refractive PE were significantly higher than the Barrett True-K (p<0.001), and the ASCRS average with ΔMR (p<0.001) respectively. The ASCRS average with ΔMR produced a significantly smaller variance of IOL PE (p<0.05). CONCLUSION: Accounting for PEs and variance, the ASCRS average IOL power with ΔMR is recommended, followed by the ASCRS average IOL power No History if without historical data.

Surgical treatment of presbyopia I

Presbyopia is an age-related condition that progressively decreases the ability to focus on near objects. Minimally invasive surgical techniques have been developed to improve near vision, including laser in situ keratomileuses (LASIK) and corneal inlay. Most have similar approaches using monovision or increasing the depth of focus. Monovision laser refractive surgery is a combination of conventional LASIK, LASIK which creates a multifocal cornea (central near or peripheral near) and aspheric micro-monovision LASIK with a special ablation profile, which develops spherical aberration. Conductive keratoplasty is a method that uses radiofrequency energy to shrink the mid-peripheral corneal stromal tissue. However, it is not used because of regression. A corneal inlay is a small device that is implanted in the corneal flap or pocket made by a femtosecond laser. It is inserted into the non-dominant eye. There are various inlays such as the Flexivue Microlens (refractive), Raindrop (corneal shape-changing), and KAMRA (small-aperture) inlays. However, the safety and effectiveness of these inlays have not been proven over a long follow-up period, so care is required when performing inlay implantation. All presbyopia treatments can improve near vision but also have limitations and side effects such as reduced far vision, contrast sensitivity, or increased glare. Therefore, it is essential to select patients carefully. Mechanisms associated with presbyopia are not fully understood, and presbyopia remains challenging for ophthalmologists.

Comparison of Hyperopic Photorefractive Keratectomy and LASIK

PURPOSE: We compared the results of photorefractive keratectomy (PRK) and laser in situ keratomileusis (LASIK) for the correction of hyperopia. METHODS: Patients who underwent PRK or LASIK, under +6.00 diopters (D) hyperopia and under −2.00 D astigmatism were included. In total, 21 patients (38 eyes) underwent PRK surgery and 25 patients (41 eyes) underwent LASIK surgery. We compared the visual acuity, refractive error, safety, and efficacy between the two groups. RESULTS: The manifest refractive spherical equivalent (MRSE) of the PRK and LASIK groups at 1 and 3 months after surgery was significantly different between the two groups (p < 0.05). However, the MRSE was not significantly different at postoperative 6 and 12 months between the two groups. The uncorrected visual acuity (UCVA) of the PRK and LASIK groups at 1 month after surgery was significantly different between the two groups (p < 0.05). However, the UCVA was not significantly different at postoperative 3, 6, and 12 months between the two groups. The best-corrected visual acuity was not significantly different at postoperative 1, 3, 6, and 12 months between the two groups. The safety index was not significantly different between the two groups at postoperative 1, 3, 6, and 12 months. The efficacy index of the PRK group was lower than that of the LASIK group at 1 month after surgery. However, the efficacy index was not significantly different at postoperative 3, 6, and 12 months between the two groups. There was no statistically significant difference between the predictability of the two groups at postoperative 1 year. CONCLUSIONS: After PRK treatment, temporary myopic deviation was observed after 1 month, but there was no significant difference between the two treatments after 3 months of follow-up. In the correction of hyperopia, there was no significant difference between PRK and LASIK in efficacy or safety.

Effect of 3% Diquafosol Tetrasodium on Tear Film Stability after Laser-assisted in situ Keratomileusis

PURPOSE: To evaluate the efficacy of 3% diquafosol tetrasodium (DQ) after laser-assisted in-situ keratomileusis (LASIK). METHODS: This prospective randomized study included 150 eyes in 75 patients who were scheduled for LASIK. The patients in the 3% diquafosol tetrasodium (DQ) group (37 patients, 74 eyes) were instructed to apply one drop of DQ, six times daily post-op, while the patients in the 0.3% sodium hyaluronate (HA) group (38 patients, 76 eyes) were instructed to apply one drop of HA, six times daily post-op. A Schirmer test, tear film break-up time (BUT), corneal and conjunctival fluorescein staining score (FLSS), and ocular surface disease index (OSDI) were evaluated pre-op and at 1, 4, and 12 weeks post-op while the tear osmolarity was evaluated pre-op and at 4 and 12 weeks post-op. RESULTS: There was no significant difference between the two groups regarding Schirmer test results or tear osmolarity and conjunctival FLSS. The BUT was significantly higher in the DQ group at 1 week and 12 weeks post-op. The corneal FLSS was significantly lower in the DQ group at 1 week, 4 weeks and 12 weeks post-op. The OSDI was significantly lower in the DQ group at 1 week post-op. CONCLUSIONS: Use of 3% diquafosol tetrasodium after surgery improved ocular dryness and increased the tear film stability.

Comparison of Laser In Situ Keratomileusis Flap Morphology and Predictability by WaveLight FS200 Femtosecond Laser and Moria Microkeratome: An Anterior Segment Optical Coherence Tomography Study

PURPOSE: To evaluate laser in situ keratomileusis (LASIK) flap thickness predictability and morphology by femtosecond (FS) laser and microkeratome (MK) using anterior segment optical coherence tomography. METHODS: Fifty-two candidates for the LASIK procedure were stratified into two groups: FS laser-assisted (Allegretto FS-200) and MK flap creation (Moria 2). Flap thickness was determined at five points. The side-cut angle was measured in three directions at the margin interface. LASIK flap assessment was performed one month postoperatively by Spectralis anterior segment optical coherence tomography. RESULTS: Fifty-two patients (93 eyes) were recruited; 49 eyes were stratified to the FS group and 44 eyes to the MK group. The FS group had relatively even flap configurations, and the MK group had meniscus-shaped flaps. Mean differences between planned and actual flap thickness were 12.93 ± 8.89 and 19.91 ± 5.77 µm in the FS and MK groups, respectively. In thin flaps (100 to 110 µm), there was a significant disparity between the two groups (7.80 ± 4.71 and 19.44 ± 4.46 µm in the FS and MK groups, respectively). However, in thicker flaps (130 µm), comparable flap thickness disparity was achieved (18.54 ± 9.52 and 20.83 ± 5.99 µm in the FS and MK groups, respectively). Mean side-cut angle was 74.29 ± 5.79 degrees and 32.34 ± 4.94 degrees in the FS and MK groups, respectively. CONCLUSIONS: Comparable flap thickness predictability was achieved in thicker flaps (130 µm), while the FS laser technique yielded a more predictable result in thinner flaps (100 to 110 µm). Different flap morphology was observed in meniscus flaps in MK-LASIK and flap morphology in FS-LASIK.

Thickness and immunohistochemistry of LASIK flaps created by different femtosecond lasers in eye-bank corneas / Espessura e imunohistoquímica de flap de LASIK criado com diferentes laseres de femtosegundo em córneas de banco de olhos

ABSTRACT Purpose: The aim of this study was to compare the corneal cell viability and thickness of LASIK flaps created by 3 femtosecond lasers in eye-bank human corneas. Methods: Forty-five eye-bank human sclerocorneal buttons (15 corneas in each group) were examined after the creation of 120 mm-thick laser-assisted keratomileusis (LASIK) flaps with 150kHz iFS In­traLase™ (IL), Z6 Femto LDV™ (LDV), or 200kHz Wavelight™ FS200 (FS200). The thickness of the flaps was measured using anterior segment optical coherence tomography (AS-OCT; Visante™). Cell viability was blindly evaluated with immunohistochemistry for keratocyte apoptosis using anti-caspase 3 antibodies. Results: The standard deviation from the intended flap thickness was less than 10 mm in all the groups. There was a statistically significant difference in corneas treated with LDV and IL with regard to the flap thickness horizontally at +3.00 mm (p=0.0124), -0.5 mm (p=0.0082), and -1.00 mm (p=0.0425) from the corneal vertex and +0.5 mm from the flap edge (p=0.0240), and those treated with LDV and FS200 with regard to the flap thickness horizontally at -0.5 mm from the corneal vertex (p=0.0082). The mean keratocyte apoptosis numbers were 13.09 ± 1.10, 15.59 ± 3.28, and 17.72 ± 1.49 in corneas treated with IL, FS200, and LDV, respectively (p<0.001). Conclusion: All 3 assessed femtosecond lasers provided predictable LASIK flap thickness. The mean stromal keratocyte apoptosis number was low in all groups.

RESUMO Objetivos: Comparar a viabilidade celular e a espessura do disco de LASIK confeccionado por três laseres de femtosegundo, em córneas humanas de banco de olhos. Métodos: Quarenta e cinco botões córneo-esclerais humanos de banco de olhos (15 córneas em cada grupo) foram examinados, após a criação de disco de LASIK com 120 mm de espessura, utilizando-se o iFS IntraLase® 150kHz (IL), o Femto LDV® Z6 (LDV), ou o Wavelight® FS200 200kHz (FS200). Tomografia de coerência óptica do seguimento anterior (OCT Visante®) foi usada para medir a espessura dos discos. A viabilidade celular foi avaliada por meio de imuno-histoquímica para apoptose dos ceratócitos, com anti-caspase 3. Resultados: O desvio padrão da espessura planejada do disco foi inferior a 10 mm em todos os grupos. Houve diferença estatisticamente significante da espessura do disco horizontalmente a +3,00 mm (p=0,0124), -0,5 mm (p=0,0082) e -1,00 mm (p=0,0425), a partir do vértice corneal, e a +0,5 mm (p=0,0240), a partir da borda do disco, em córneas tratadas por LDV e IL, e horizontalmente a -0,5 mm a partir do vértice corneal, entre LDV e FS200 (p=0,0082). A média de apoptose dos ceratócitos foi (13,09 ± 1,10), (15,59 ± 3,28) e (17,72 ± 1,49), em córneas tratadas pelo IL, FS200 e LDV, respectivamente (p<0,001). Conclusão: Todos os três laseres de femtosegundo estudados produziram disco de LASIK com predictibilidade de espessura. A média de apoptose dos ceratócitos foi baixa em todos os grupos.

Corneoscleral contact lenses fitting on irregular corneas after laser-assisted in situ keratomileusis / Lentes de contato corneoesclerais adaptadas em córneas irregulares após cirurgia LASIK

ABSTRACT Purpose: We aimed to describe the outcomes of corneoscleral contact lens fitting with multi-aspherical geometry designs in patients with irregular corneas after laser-assisted in situ keratomileusis (LASIK). Methods: This was a retrospective series of 18 patients (age, 26-38 years) selected from an eye clinic database. Participants were required to have unsatisfactory visual acuity with their current contact lenses or spectacles after LASIK for myopia correction. All patients were fitted with corneoscleral contact lenses designed to correct corneal surface irregularities. A diagnostic trial set was used for fitting, and assessments were performed according to a standardized methodology. Subjective comfort, visual acuity, central corneal thickness, endothelial cell count, and corneal-compensated intraocular pressure were evaluated. The follow-up period was one year. Results: Contact lens use was discontinued in 3 patients, thus leaving 24 eyes from 8 females and 7 males for analysis. The fitting characteristics were optimal in terms of lens position and movement. Statistically significant improvements were found in the best spectacle-corrected vision from before fitting to the visual acuity after fitting (p<0.001). Moreover, the patients reported high subjective comfort ratings and usage times (12.98 ± 2.3 hours/day). After one year of wear, visual acuity, subjective comfort, and usage time were maintained. No statistically significant adverse changes developed in the corneas over this period. Conclusion: Corneoscleral contact lenses with a multi-aspherical geometry design provide optimal visual acuity, improved comfort, and prolonged usage times in patients with irregular corneas after LASIK.

RESUMO Objetivo: Descrever os resultados do ajuste de lentes de contato corneoesclerais com geometria multiasférica em pacientes com córneas irregulares após cirurgia de ceratomileuse in situ assistida por laser (LASIK). Métodos: Esta foi uma série retrospectiva de 18 pacientes (idade, 26-38 anos) selecionados a partir de um banco de dados de uma clínica oftalmológica. Os participantes foram escolhidos ao manifestaram acuidade visual insatisfatória com suas lentes de contato ou óculos atuais depois de terem sido submetidos à LASIK para correção de miopia. Todos os pacientes receberam lentes de contato corneoesclerais projetadas para corrigir irregularidades na superficie da córnea. Um conjunto diagnóstico de prova foi usado para a adaptação e as avaliações foram feitas de acordo com uma metodologia padronizada. O conforto subjetivo, a acuidade visual, a espessura central da córnea, a contagem de células endoteliais e a pressão intraocular compensada da córnea foram avaliados. O período de acompanhamento foi de um ano. Resultados: O uso de lentes de contato foi descontinuado em 3 pacientes, deixando 24 olhos de 8 mulheres e 7 homens para análise. As características de adaptação foram ótimas em termos de posição e movimento da lente. Melhorias estatisticamente significativas foram encontradas na melhoria da visão corrigida por óculos antes de se ajustar a acuidade visual após a adaptação (p<0,001). Além disso, os pacientes relataram altos índices subjetivos de conforto e tempo de uso (12,98 ± 2,3 horas/dia). Após um ano de uso, a acuidade visual, o conforto subjetivo e o tempo de uso foram mantidos. Não houve alterações adversas estatisti­camente significativas nas córneas ao longo deste período. Conclusão: As lentes de contato corneoesclerais com projeto geométrico multiasférico proporcionam acuidade visual ideal, maior conforto e tempo de uso prolongado em pacientes com córneas irregulares após o LASIK.

Focal phototherapeutic keratectomy for the treatment of apical leucoma syndrome / PTK focal para o tratamento da síndrome do leucoma apical

ABSTRACT The following report describes a case of apical leucoma syndrome after hyperopic photorefractive keratectomy following hyperopic laser in situ keratomileusis and the subsequent treatment of this complication with focal phototherapeutic keratectomy. The patient underwent focal transepithelial phototherapeutic keratectomy of 70 mm ablation and 1.5 mm diameter after pupil and ablation offset correction. After 1 year, significant improvement in vision was observed and only slight residual opacity remained on biomicroscopy and optical coherence tomography. Focal phototherapeutic keratectomy was effective and safe for the treatment of this complication.

RESUMO O relato a seguir descreve um caso da síndrome do Leucoma Apical após cirurgia ceratorrefrativa hipermetrópica depois de Laser hiperópico in situ keratomileusis, e o subsequente tratamento desta complicação com ceratectomia fototerapêutica focal. O paciente foi submetido à ceratectomia fototerapêutica focal transepitelial com ablação de 70 mm e diâmetro de 1,5 mm, após correção de offset pupilar. Depois de um ano, foi observada uma melhora significativa da acuidade visual permanecendo apenas leve opacidade residual na biomicroscopia e tomografia de coerência óptica. A ceratectomia fototerapêutica focal foi efetiva e segura para o tratamento desta complicação.