Comparison of intraocular lens power prediction accuracy of formulas in American Society of Cataract and Refractive Surgery post-refractive surgery calculator in eyes with prior radial keratotomy

Purpose: To evaluate the accuracy of intraocular lens (IOL) power prediction of the formulas available on the American Society of Cataract and Refractive Surgery (ASCRS) post?refractive calculator in eyes with prior radial keratotomy (RK) for myopia. Methods: This retrospective study included 25 eyes of 18 patients whose status was post?RK for treatment of myopia, which had undergone cataract extraction with IOL implantation. Prediction error was calculated as the difference between implanted IOL power and predicted power by various formulae available on ASCRS post?refractive calculator. The formulas compared were Humphrey Atlas method, IOLMaster/Lenstar method, Barrett True?K no?history formula, ASCRS Average power, and ASCRS Maximum power on ASCRS post?refractive calculator. Results: Median absolute errors were the least for Barrett True?K and ASCRS Maximum power, that is, 0.56 (0.25, 1.04) and 0.56 (0.25, 1.06) D, respectively, and that of Atlas method was 1.60 (0.85, 2.28) D. Median arithmetic errors were positive for Atlas, Barrett True?K, ASCRS Average (0.86 [?0.17, 1.61], 0.14 [?0.22 to 0.54], and 0.23 [?0.054, 0.76] D, respectively) and negative for IOLMaster/Lenstar method and ASCRS Maximum power (?0.02 [?0.46 to 0.38] and ? 0.48 [?1.06 to ? 0.22] D, respectively). Multiple comparison analysis of Friedman抯 test revealed that Atlas formula was significantly different from IOLMaster/ Lenstar, Barrett True?K, and ASCRS Maximum power; ASCRS Maximum power was significantly different from all others (P < 0.00001). Conclusion: In post?RK eyes, Barrett True?K no?history formula and ASCRS Maximum power given by the ASCRS calculator were more accurate than other available formulas, with ASCRS Maximum leading to more myopic outcomes when compared to others

Comparison of accuracy of intraocular lens calculation formulas in cataract eyes with prior radial keratotomy and axial length longer than 28mm / 国际眼科杂志(Guoji Yanke Zazhi)

AIM: To compare the accuracy of different intraocular lens(IOL)calculation formulas in cataract patients with axial length longer than 28mm and a history of radial keratotomy(RK).METHODS: Retrospective study. The medical records of 19 cataract patients(29 eyes)after RK and with axial length longer than 28mm who underwent cataract surgery from January 2011 to July 2020 in Beijing Tongren Hospital were analyzed. The absolute error(AE)of the difference among three different formulas was calculated. AE refers to the absolute value between the actual spherical equivalent after cataract surgery and the spherical equivalent predicted by the IOL formula. The AE values of the three formulas and the percentages of eyes with AE≤0.5, 0.75, 1.0, and 2.0D were calculated and compared.RESULTS: The AE values of the three formulas were significantly different(χ2=8.759, P=0.013). The Barrett True-K formula had the smallest median AE, which was only 0.62(0.20, 1.15)D, followed by the Haigis formula 0.76(0.34, 1.26)D, and the Holladay 1(D-K)formula had the largest 1.01(0.49, 1.62)D. The percentages of affected eyes with AE ≤0.5, 0.75, 1.0, and 2.0D for the Barrett True-K formula were 48%, 59%, 69%, and 93%, which were equal to or higher than the other two formulas.CONCLUSION: The Barrett True-K formula is more recommended among the three formulas for cataract patients after RK and with axial length longer than 28 mm.

Laser topoguiado como redutor de aberrações ópticas pós ceratotomia radial e LIO multifocal / Topoguided laser as a reducer of optical aberrations after radial keratotomy and multifocal LIO

Resumo A cirurgia de catarata com implante de lente intra-ocular é uma das cirurgias mais realizadas no mundo e, atualmente, os pacientes que se submetem a essa cirurgia podem utilizar o implante com lente intraocular (LIO) multifocal como alternativa ao uso de óculos. Um grande desafio para o cirurgião são os pacientes já submetidos previamente a ceratotomia radial (RK), pois além de terem um cálculo biométrico mais desafiador, apresentam importantes aberrações ópticas corneanas, sendo uma contra-indicação para o uso de lentes multifocais para a maioria dos oftalmologistas. Neste artigo, relatamos o caso de uma paciente que foi submetida, na juventude, a uma RK e passou a referir importante incômodo visual após a correção de catarata com facectomia e implante de LIO multifocal. Esta paciente foi submetida a uma ceratectomia fotorrefrativa (PRK) para diminuir as irregularidades da córnea com boa evolução clínica e resultado visual satisfatório. Esse caso chama a atenção para a alternativa do excimer laser topoguiado em casos semelhantes e alerta para o risco do uso desse tipo de lente em córneas irregulares.

Abstract Cataract surgery with intraocular lens implantation is one of the most commonly performed surgeries in the world and, currently, patients who undergo this surgery can use the multifocal intraocular lens (IOL) implant as an alternative to wearing glasses. A great challenge for the surgeon are patients who have previously undergone radial keratotomy (RK), because in addition to having a more challenging biometric calculation, they also have important corneal optical aberrations, being a contraindication for the use of multifocal lenses for most patients. ophthalmologists. In this article, we report the case of a patient who underwent a RK in her youth and started to report an important visual discomfort after cataract correction with facectomy and multifocal IOL implantation. This patient underwent a photorefractive keratectomy (PRK) to reduce corneal irregularities with good clinical evolution and satisfactory visual result. This case draws attention to the alternative of topography-guided laser excimer in similar cases and warns of the risk of using this type of lens in irregular corneas.

Long-term Results of Mini Asymmetric Radial Keratotomy and Corneal Cross-linking for the Treatment of Keratoconus

PURPOSE: To investigate the long-term results (at least 5 years of follow-up) of the mini asymmetric radial keratotomy (MARK) and corneal cross-linking (CXL) combined intervention, also known as the ‘Rome protocol,’ for patients with progressive stage I and II keratoconus and contact lens intolerance. METHODS: This was a retrospective observational case series. Fifteen eyes of 12 patients were evaluated, with a mean follow-up of 6.9 years. To assess the efficacy and stability of the MARK + CXL combined protocol, best spectacle-corrected visual acuity, mean pachymetry, and mean keratometry were recorded preoperatively and at least 1, 3, and 5 years postoperatively. Statistical analysis was performed using the R platform and involved the Wilcoxon signed-rank and Kruskal-Wallis non-parametric tests. RESULTS: Best spectacle-corrected visual acuity improved for all patients, from 0.46 ± 0.69 logarithm of the minimum angle of resolution (20 / 60) to 0.15 ± 0.69 logarithm of the minimum angle of resolution (20 / 30, p = 0.0006), while mean pachymetry increased in 93% of patients, from 442.80 ± 61.02 to 464.50 ± 62.72 µm (p = 0.003). Lastly, mean keratometry improved in 87% of patients after 6.9 years of observation from 48.82 ± 5.00 to 43.25 ± 3.58 diopters (p = 0.008). No intraoperative or postoperative complications were observed. CONCLUSIONS: The MARK + CXL combined protocol was effective in treating keratoconus by halting corneal thinning and bulging. In addition, this procedure significantly improved visual acuity based on long-term follow-up data. Analysis of data from a larger cohort of patients would be useful to support these findings.

Clinical observation of intraocular lens calculation in eyes with previous radial keratotomy / 国际眼科杂志(Guoji Yanke Zazhi)

@#AIM: To evaluate the accuracy of the Barrett True K intraocular lens(IOL)calculation formulas in eyes with previous radial keratotomy(RK).<p>METHODS: From February 2017 to February 2019, 42 eyes of 22 cataract patients with previous RK were selected in our hospital. Two methods were used to calculate IOL refraction before surgery: 1)Selected the smallest anterior surface K value in the area of 3mm central corneal diameter, used SRK/T formula, the target refraction was set at -1.0D; 2)Used Barrett True K on-line calculation formula, the mode of RK was selected and the target refraction was set at -1.0D. Three months after operation, the refractive state of the eyes was examined and the refractive errors calculated by the two methods were compared.<p>RESULTS: The average refractive error of Barrett formula method was 0.61(-0.37, 0.88)3mo after operation, which was significantly lower than that of traditional formula method 0.35(-0.25, 0.63)D(<i>P</i><0.05). There was no significant difference in absolute refractive error between the two methods(<i>P</i>>0.05). The refractive errors of traditional formula method in the range of ±0.5D, ±1.0D, ±2.0D accounted for 21%, 45%, 90% respectively. The refractive errors of Barrett formula method in the range of ±0.5D, ±1.0D, ±2.0D accounted for 31%, 74%, 100% respectively(<i>P</i><0.05).<p>CONCLUSION: Barrett True K online formula applied to cataract patients after RK can achieve satisfactory refractive status.

Non-Descemet stripping automated endothelial keratoplasty for post radial keratotomy corneal edema

An elderly male with monocular status presented with complaints of gradual loss of vision in his left eye. Slit-lamp evaluation revealed postradial keratotomy (RK) corneal decompensation. He underwent non-Descemet stripping automated endothelial keratoplasty (nDSAEK) in his left eye. Postoperatively, his visual acuity improved from counting finger at 1 m to 20/200, J5. Graft adherence was good. A preexisting epiretinal membrane with macular edema was noted, but our patient refused any further surgical intervention for the same. In conclusion, nDSAEK may be considered as an effective treatment modality for the management of post-RK corneal decompensation.

Design and inspection of multifunctional intraocular lens calculation formula / 中华实验眼科杂志

Objective To establish a conventional intraocular lens (IOL) calculation formula which is applicable to eyeballs with abnormal data and laser in situ keratomileusis (LASIK) postoperative eyes.Methods A case-series study was adopted.According to the classical optical theory,a normal IOL implanted eye has the following characteristics:when light is refracted by cornea and arrives on the IOL plane,the value of refractive power (F1) + IOL refractive power (F2) =the value of refractive power which is suitable for vitreous body depth (F3).Thereafter,a mathematical model was built on the basis of theory,experience,and regression analysis data after IOL implantation surgeries.Furthermore,based on the new LASIK postoperative cornea curvature modified formula,the two kinds of IOL calculation programs of conventional and LASIK postoperative eyes were established.The test data was collected from 644 patients who had undergone the cataract extractions and IOL implantation surgeries (600 physiological cornea eyes,7 radial keratotomy [RK] eyes and 37 LASIK postoperative eyes) at the Affiliated Drum Tower Hospital of Nanjing University Medical School.Through the analysis of these data,the new formulas were examined.Results With IOL refractive power of 607 eyes (including 7 RK postoperative eyes),the average error of XLQ formula (the tentative name of the established formula in this study)was 0.1 D,and the 95％ limits of agreement range was-1.1 to + 1.2 D.The error range of IOL refractive power predicted by XLQ,SRK-T and Haigis formulas was-2.21 to +2.25 D,-5.10 to +5.63 D and-3.00 to +3.18 D,respectively,the absolute average error of IOL refractive power predicted by the three formulas was (0.43 ± 0.28),(0.74 ± 0.53) and (0.79 ± 0.49) D,respectively.Compared with SRK-T and Haigis formulas,the average error of IOL refractive power predicted by XLQ formula was Lower,with significant differences between them (both at P =0.000).The error value of IOL refractive power predicted by XLQ formula had no statistical correlations with axial length (AL),keratometry (K) and A constant respectively (all at P＞0.05),while the error value predicted by SRK-T and Haigis formulas had statistical correlations with AL,K and A constant,respectively (all at P＜0.05).Thirty-seven patients who had conducted LASIK for myopia (and whose IOL refractive power value were predicted by XLQ formula) had been undergone the postoperative examination.Comparing the predicted and actual value,the error range of IOL refractive power was-0.52 to +1.18 D,and the absolute average error was (0.49±0.26)D.Conclusions The conventional mode of the XLQ formula established in this study can be used in the cases with broad values of axial length,corneal curvature and A constant,as well as various types of physiological cornea and RK postoperative eyes;the dedicated mode is suitable for LASIK postoperative eyes of myopia.

Correlación de los valores queratométricos del Pentacam y el método de Maloney / Correlation of the keratometric values of Pentacam and Maloney's method

Objetivo: correlacionar los valores queratométricos obtenidos por el programa Holladay Report del Pentacam en ojos operados de queratotomía radial con diagnóstico de catarata, y los obtenidos a través del método de Maloney. Métodos: se realizó un estudio observacional prospectivo y descriptivo a 18 ojos miopes de 14 pacientes portadores de opacidades cristalinianas previamente sometidos a queratotomía radial que acudieron al Servicio de Catarata del Instituto Cubano de Oftalmología Ramón Pando Ferrer en el período comprendido de febrero a noviembre del año 2013. Se utilizó el Pentacam para obtener de forma directa el poder refractivo corneal utilizando programas diseñados con este fin, y posteriormente compararlo con el obtenido por el método de Maloney. Resultados: se obtuvo una correlación positiva al comparar las lecturas queratométricas equivalentes a 1 mm (r= 0,962); 2 mm (r= 0,845); 3 mm (r= 0,985); 4 mm (r= 0,988); 4,5 mm (r= 0,988) y central (r= 0,976) obtenidas en el programa Holladay Report del Pentacam, y los valores queratométricos aportados por el método de Maloney, lo cual fue estadísticamente significativo (p= 0,001). Conclusiones: el programa Holladay Report del Pentacam aporta poderes corneales que no difieren estadísticamente de los obtenidos por el método de Maloney en pacientes con cirugía refractiva corneal previa y catarata con criterio quirúrgico(AU)

Objective: to correlate the keratometric values from the Pentacam´s Holladay Report software in operated eyes which underwent radial keratotomy with cataract diagnosis and those of Maloney´s method. Method: prospective, descriptive and observational study conducted in 18 myopic eyes from 14 patients who had crystalline opacities and had undergone radial keratotomy. They had gone to the cataract service of Ramon Pando Ferrer Cuban Institute of Ophthalmology from February to November 2013. Pentacam was used to directly estimate the corneal refractive power by using tailor-made software for this purpose, and then compare it with the values obtained by Maloney´s method. Results: there was positive correlation when comparing the keratometric readings of 1 mm (r= 0.962); 2 mm (r= 0.845); 3 mm (r= 0.985); 4 mm (r=0.988); 4.5 mm (r= 0.988) and central (r= 0.976) in the Pentacam´s Holladay Report software and the keratometric values of the Maloney's method, which was statistically significant (p= 0,001). Conclusions: pentacam´s Holladay Report software reached corneal power values that do not differ statistically from those of Maloney´s method in patients who had previously undergone corneal refractive surgery and cataract with surgical criteria(AU)

Two cases of ultrathin Descemet stripping automated endothelial keratoplasty utilizing a graft that had undergone radial keratotomy.

This is a report of two cases in which tissue that had undergone radial keratotomy (RK) was utilized for double‑pass ultrathin Descemet stripping automated endothelial keratoplasty (UT‑DSAEK). Postoperative slit‑lamp examination, visual acuity, anterior segment optical coherence tomography, and specular microscopy were available 30 months after surgery. Both corneas from a donor, who had undergone RK several years before his demise, and were otherwise suitable for endothelial keratoplasty were prepared for UT‑DSAEK using double‑pass dissection using first a 300 μm microkeratome head and then a 130 μm microkeratome head (ALTK system, Moria, Antony, France). After the second cut, the tissue was punched to 9.0 mm and transplanted in two eyes with endothelial decompensation according to standard technique. As early as 3 months after surgery, both patients had 20/25 best‑corrected visual acuity, which remained stable for the following 27 months. Postoperative endothelial cell loss was 34% and 57% at 2.5 years. In conclusion, post‑RK donor tissue can be used for UT‑DSAEK.

Combined Corneal Collagen Cross-linking and Mini Asymmetric Radial Keratotomy for the Treatment of Keratoconus.

Objective: The primary objective of this study was to quantify the visual improvement and the reduction of corneal curvature achieved through association of Mini Asymmetric Radial Keratotomy (MARK) and Corneal Collagen Cross-linking (CXL). Design: Retrospective clinical trial. Methods: Sixteen eyes (sixteen patients) were included. Computerized corneal topography and Scheimpflug camera equipment were used to measure higher order corneal aberrations before treatment and during follow-up. Outcome parameters, including uncorrected visual acuity and best corrected visual acuity, have been measured as well. Examinations were performed at 3, 6, 12 and 24 months following both MARK and CXL. Results: A sharp reduction of both corneal curvature and corneal aberrations was observed after MARK surgery, followed by a smaller improvement following CXL treatment. Conclusion: The combination of MARK with CXL offers a significant improvement of visual acuity and a reduction of corneal curvature along with the corneal reinforcement provided by CXL.

Long-Term Results of Three Cases of Radial Keratotomy

PURPOSE: To report the long-term results concerning refractive changes after radial keratotomy in 6 eyes of 3 patients. CASE SUMMARY: We observed 3 patients who underwent radial keratotomy over 25 years previously. The positive effect of this surgery on the correction of refractive error decreased with increasing post-surgery time and myopic refractive errors accompanying astigmatism recurred. On average, refractive errors improved to 3.375 diopter (D) and corneal power improved to 2.954 D; in all cases, uncorrected visual acuities were not significantly improved. CONCLUSIONS: The effect of radial keratotomy on the correction of refractive errors decreased with time due to regression; myopic refractive errors recurred in the long-term.

Simulación de queratotomía arqueada por medio de un modelo de elementos finitos: aplicación de una plataforma de interacción entre Matlab y COMSOL Multiphysics / Simulation of arcuate keratotomy using the finite elements method: an application of an interaction platform of Matlab and COMSOL Multiphysics

La queratotomía radial es uno de los métodos quirúrgicos empleados para corregir los defectos ópticos de las personas; ésta ha sido ampliamente estudiada, e incluso se han propuesto nomogramas que permiten predecir los resultados de algunas geometrías; a pesar de esto, las experiencias postoperatorias han demostrado que la tasa de éxito de las cirugías es baja, ya que se presenta hipocorrección o hipercorrección de los pacientes, obligándolos a usar ayudas externas o llevándolos a someterse nuevamente a una cirugía. Teniendo en cuenta esto, se desarrolló una plataforma para simular estas cirugías por medio del método de elementos finitos, empleando los programas Matlab y COMSOL Multiphysics. Por medio de la rutina creada es posible obtener un modelo de la córnea preoperatoria que se asemeje tanto en geometría, como en condiciones de esfuerzo, a la córnea real; adicionalmente, es posible adaptar la geometría de la queratotomía radial que desee simularse. Se realizaron simulaciones para una cirugía compuesta de dos arcos y otra de tres arcos; los resultados obtenidos demuestran la capacidad de la simulación numérica para avanzar en el desarrollo de la cirugía refractiva, al ser posible estudiar parámetros, que de forma experimental, son difíciles de tener en cuenta, como la geometría inicial de la córnea y la edad del paciente, lo cual influye en el módulo de elasticidad del material; por otra parte, se encontró que esta aplicación es una potencial herramienta para los oftalmólogos, pues tiene la capacidad de predecir los resultados postoperatorios.

Radial keratotomy is used as a methodology to correct refractive errors. This surgery has been widely studied and also nomograms have been proposed in order to predict postoperative results of some types of keratotomies. Despite these eff orts, surgical evidence has shown a low success rate because of undercorrection or overcorrection, forcing patients to use spectacles or contact lenses, after surgery, or even leads them to a new procedure. A simulation platform was developed in an attempt to study these surgeries, employing the finite element method, using Matlab and COMSOL Multiphysics simultaneously. The routine is capable of simulate the preoperative cornea in terms of geometry and stress configuration. Also, it could be adapted to simulate any kind of radial keratotomy LASIK and PRK surgeries. Simulations for a double arc keratotomy and a triple arc keratotomy were developed. Results provide evidence of the capability of the platform to improve knowledge of refractive surgery taking into account the possibility to analyze the effect produced by corneal geometry and patient age, which aff ects the elastic modulus of the material, parameters difficult to analyze in an in-vivo experiment. Besides, it demonstrates the potential of the program as a tool for the surgeon to plan refractive surgery.

A Case of Cataract Surgery after Radial Keratotomy

PURPOSE: To report a patient who underwent successful cataract surgery without wound dehiscence in the eye that had undergone previous radial keratotomy by performing a clear corneal incision between previous incisions. CASE SUMMARY: A 59-year-old female visited our medical center for decreased vision. The patient underwent radial keratotomy for correction of myopia in both eyes 11 years prior. On slit-lamp examination, cataract and eight radial keratotomy incisions were found. Phacoemulsification and posterior capsule intraocular lens implantation were performed for both eyes at a one-week interval. For the right eye, a clear corneal incision was made over the previous incision scar and wound dehiscence was successfully managed by prompt corneal suturing. For the left eye, a clear corneal incision was made between the previous incision scars, and wound dehiscence did not occur. CONCLUSIONS: As radial keratotomy patients age, cataract surgery should be considered. A successful surgery was possible without wound dehiscence in an eye that had undergone previous radial keratotomy in which a clear corneal incision was made between previous incision scars.

Laser in-situ keratomileusis for refractive error following radial keratotomy.

Aim: To evaluate the safety and efficacy of laser in-situ keratomileusis (LASIK) in eyes with residual/induced refractive error following radial keratotomy (RK). Design: Retrospective study. Materials and Methods: A retrospective analysis of data of 18 eyes of 10 patients, who had undergone LASIK for refractive error following RK, was performed. All the patients had undergone RK in both eyes at least one year before LASIK. Parameters like uncorrected visual acuity (UCVA), best-corrected visual acuity (BCVA), contrast sensitivity, glare acuity and corneal parameters were evaluated both preoperatively and postoperatively. Statistical Software: STATA-9.0. Results: The mean UCVA before LASIK was 0.16±0.16 which improved to 0.64 ± 0.22 (P < 0.001) after one year following LASIK. Fourteen eyes (out of 18) had UCVA of ≥ 20/30 on Snellen's acuity chart at one year following LASIK. The mean BCVA before LASIK was 0.75 ± 0.18. This improved to 0.87 ± 0.16 at one year following LASIK. The mean spherical refractive error at the time of LASIK and at one year after the procedure was –5.37 ± 4.83 diopters (D) and –0.22 ± 1.45D, respectively. Only three eyes had a residual spherical refractive error of ≥ 1.0D at one year follow-up. In two eyes, we noted opening up of the RK incisions. No eye developed epithelial in-growth till 1 year after LASIK. Conclusion: LASIK is effective in treating refractive error following RK. However, it carries the risk of flap-related complications like opening up of the previously placed RK incisions and splitting of the corneal flap.

Ceratectomia fotorrefrativa com mitomicina-C personalizada pela frente de onda corneana para o tratamento de hipermetropia após ceratotomia radial / Corneal wavefront-guided photorefractive keratectomy with mitomycin-C for consecutive hyperopia after radial keratotomy

OBJETIVO: Avaliar a eficácia, previsibilidade e estabilidade da ceratectomia fotorrefrativa (PRK) guiada pela frente de onda corneana para o tratamento da hipermetropia secundária à ceratotomia radial. MÉTODOS: Este estudo prospectivo analisou 60 olhos de 36 pacientes consecutivos, submetidos a PRK personalizado com o laser Esiris-Schwind. A técnica constou de desepitelização mecânica, fotoablação e utilização de mitomicina-C 0,02 por cento. Os pacientes foram acompanhados por 12 meses. RESULTADOS: O intervalo médio entre a ceratotomia radial e o PRK foi de 18,4 anos ± 3,8 (DP); o equivalente esférico (EE) médio antes da ceratotomia radial era -4,35 dioptrias (D) ± 1,55. As medidas prévias ao PRK mostraram grau esférico médio de +5,00 D ± 2,28, astigmatismo médio de -1,47 D ± 1,06, EE médio de +4,27 D ± 2,18 e AV corrigida (AVcc) média de 0,174 ± 0,139 (logMAR). O EE médio programado no laser foi +4,74 D ± 2,11. Os resultados encontrados um ano após a cirurgia foram: EE médio de +0,04 D ± 1,03 (P<0,001), astigmatismo médio de -1,03 ± 0,75 D (P=0,015), AV média sem correção de 0,265 ± 0,197 e AVcc de 0,079 ± 0,105 (P<0,001). A AVcc mostrou ganho médio de uma linha; 20 olhos (33,3 por cento) melhoraram duas ou mais linhas e somente um olho perdeu duas linhas. Ocorreu redução estatisticamente significante do coma (P=0,002), trefoil (P=0,004), aberração esférica (P<0,001) e quatrefoil (P=0,002). Houve 48 olhos (80 por cento) entre ± 1,00 D do EE planejado. A regressão média entre seis e 12 meses foi de +0,17 ± 0,67 D. CONCLUSÃO: O PRK personalizado pela frente de onda corneana foi eficaz, previsível e estável pelo período de um ano para a redução da hipermetropia após a ceratotomia radial. No pós-operatório, observou-se melhora significativa da AVsc, AVcc e das aberrações corneanas. Número do ClinicalTrials.gov:NCT00917657

PURPOSE: To assess the efficacy, predictability and stability of corneal wavefront-guided photorefractive keratectomy (PRK) for correcting hyperopia and astigmatism after radial keratotomy. METHODS: In a prospective study, 60 eyes of 36 consecutive patients were treated with corneal wavefront-guided PRK with 0.02 percent mitomycin-C using an Esiris-Schwind excimer laser. Corneal epithelium was mechanically removed. All patients were followed-up for 12 months. RESULTS: The mean time between radial keratotomy and PRK was 18.4 years ± 3.8 (SD); mean spherical equivalent (SE) before radial keratotomy was -4.35 diopters (D) ± 1.55. Before PRK, the mean sphere was +5.00 D ± 2.28, mean astigmatism was - 1.47 D ± 1.06, mean SE was +4.27 D ± 2.18, and the mean best-corrected visual acuity (BCVA) was 0.174 ± 0.139 (logMAR). The planned laser SE correction was +4.74 D ± 2.11. No intraoperative complications were noted. At 12 months, mean SE was +0.04 D ± 1.03 (P<0.001), mean astigmatism was -1.03 ± 0.75 D (P=0.015), mean UCVA was 0.265 ± 0.197, and mean BCVA was 0.079 ± 0.105 (P<0.001). There was a mean gain of 1 line of BCVA and 20 eyes (33.3 percent) gained 2 or more lines. Only one eye lost 2 lines. A significant decrease in coma (P=0.002), trefoil (P=0.004), spherical aberration (P<0.001) and quatrefoil (P=0.002) was observed. Forty eight eyes (80 percent) were within ± 1.0 D of intended SE. Mean regression from 6 to 12 months was +0.17 ± 0.67 D. CONCLUSION: Corneal wavefront-guided PRK was effective, predictable and stable after one year of follow-up for the treatment of hyperopia after radial keratotomy. A significant improvement in UCVA, BCVA and corneal aberrations was obtained. ClinicalTrials.gov Identifier: NCT00917657

LASIK surgery in patients with residual refractive errors after radial keratotomy / 国际眼科杂志(Guoji Yanke Zazhi)

·AIM: To study the results and complications of LASIK surgery after radial keratotomy.·METHODS: This descriptive study was carried out in Yazd LASIK Center, Yazd, Iran. Cases included all patients who had been operated between April 2003 and Septem-ber 2006. Data were collected via a special questionnaire and analyzed by SPSS software and paired t-test. ·RESULTS: Samples included 33 eyes of 23 patients of whom 11 (48%) were women and 12 (52%) were men. Their age ranged from 28 to 49 years old and the mean age was 31.6 years old. Two cases (6%) had openings of the previous radial keratotomy incisions during flap lifting and one case (3%) had moderate non-infec-tious keratitis. The mean preoperative spherical equivalent (SE) was -2.17±0.94D, while the posto-perative SE was -0.17±0.19D, the difference of which was significant (P=0.0001). Mean preoperative uncorrected visual acuity (UCVA) was 0.07±0.02 and the postopera-tive was 0.88±0.16, the difference of which was also significant (P=0.0001). The mean best spectacle correct-ed visual acuity prior to the operation was 0.93±0.08 and 0.92±0.08 after the operation, the difference of which was not significant (P=0.268).·CONCLUSION: LASIK surgery could improve residual myopia after the radial keratotomy without major complications during or postoperation, but necessity of the second procedure must be pondering and require careful case selection and assessment.

Ceractomia fotorrefrativa (PRK) com mitomicina C baseada na análise de frentes de onda corneanas para o tratamento da hipermetropia consecutiva à ceratotomia radial / Corneal wavefront-guided photorefractive keratectomy (PRK) with adjunctive mitomycin C (MMC) for the treatment of hyperopia after radial keratotomy

OBJETIVO: Avaliar a eficácia, estabilidade, previsibilidade e segurança da ceratectomia fotorrefrativa (PRK) guiada pelas frentes de onda corneana para o tratamento da hipermetropia secundária à ceratotomia radial (CR). MÉTODOS: Foram avaliados prospectivamente 61 olhos de 39 pacientes consecutivos, submetidos a PRK personalizado com o laser Esiris-Schwind. A técnica constou de desepitelização mecânica, fotoablação, e utilização de mitomicina C (MMC) 0,02% por 20 ou 40 segundos. A MMC foi aplicada por 40 segundos em 17 olhos (27,9%) que haviam sido submetidos a ablações mais profundas do que 100 ?m ou apresentavam córneas previamente suturadas. As avaliações pós-operatórias foram realizadas após sete dias, um, seis, 12 e 24 meses. Todos os olhos foram avaliados após um ano e dois anos. RESULTADOS: O intervalo médio entre a CR e o PRK foi de 18,8 anos ± 3,8 (DP); o equivalente esférico (EE) médio antes da ceratotomia radial era -4,10 dioptrias (D) ± 1,44. As medidas prévias ao PRK mostraram EE médio de +4,17 D ± 1,97; astigmatismo médio de -1,39 D ± 1,04; AV com correção (AVcc) média de 0,161 ± 0,137 (logMAR); e curvatura corneana média de 35,85 ± 3,60 D. Os resultados encontrados dois anos após a cirurgia foram: EE médio de 0,14 ± 0,99 D (p < 0,001); astigmatismo médio de -1,19 ± 1,02 D (p = 0,627); AV sem correção (AVsc) média de 0,265 ± 0,196 (p < 0,001); AVcc média de 0,072 ± 0,094 (p < 0,001); e curvatura corneana média de 39,01 ± 3,18 D (p < 0,001). AVsc igual ou melhor a 20/25 foi observada em 38% dos olhos e igual ou melhor a 20/40 em 69%. A AVcc melhorou em 62,3% dos olhos, sendo que 21 olhos (34,4%) melhoraram uma linha e outros 17 olhos (27,9%), duas ou mais linhas. Um olho (1,6%) perdeu duas linhas devido ao astigmatismo irregular ocasionado por opacificação corneana periférica. Outro olho perdeu três linhas pelo desenvolvimento de ectasia corneana entre seis e 24 meses, devido ao alargamento progressivo de uma incisão radial inferior...

PURPOSE: To assess the efficacy, stability, predictability and safety of corneal wavefront-guided photorefractive keratectomy (PRK) for correcting hyperopia after radial keratotomy (RK). METHODS: In a prospective study, 61 eyes of 39 consecutive patients were treated with PRK using an Esiris-Schwind excimer laser. Corneal epithelium was mechanically removed, followed by photoablation and use of 0.02% mitomycin C (MMC) for 20 or 40 seconds. MMC was used for 40 seconds in 18 eyes (27.9%) which underwent ablations deeper than 100 micron or had previous corneal sutures. Postoperative evaluations were performed after seven days, six, 12 and 24 months. All patients were followed up for two years. RESULTS: The mean time between RK and PRK was 18.8 years ± 3.8 (SD); mean spherical equivalent (SE) before RK was -4.10 diopters (D) ± 1.44. Before PRK, the mean SE was +4.17 D ± 1.97, mean astigmatism was -1.39 D ± 1.04, the mean best-corrected visual acuity (BCVA) was 0.161 ± 0.137 (logMAR) and the mean corneal curvature was 35.85 ± 3.60 D. At 24 months, mean SE was 0.14 ± 0.99 D (p < 0.001), mean astigmatism was -1.19 ± 1.02 D (p = 0.627), mean UCVA was 0.265 ± 0.196 (p < 0.001), mean BSCVA was 0.072 ± 0.094 (p < 0.001) and the mean corneal curvature was 39.01 ± 3.18 D (p < 0.001). UCVA was 20/25 or better in 38% of eyes and 20/40 or better in 69%. BCVA improved in 62.3% of eyes, with 21 (34.4%) gaining one line and 17 (27.9%), two or more lines. One eye (1.6%) lost two lines due to irregular astigmatism and peripheral haze. Another eye lost three lines due to keratectasia occurring between six and 24 months resulting from widening of an inferior radial incision that was later sutured. Thirty eyes (49.2%) were within ± 0.50 D of intended SE and 45 (73.8%) were within ± 1.00 D. From six to 24 months, the mean SE...

Láser in situ keratomileusis en la corrección de miopía y astigmatismo residual posqueratotomía radial en casos seleccionados / Laser in situ keratomileusis to correct myopia and residual astigmatism after radial keratotomy in selected case

OBJETIVO: Evaluar la seguridad y la eficacia del tratamiento con láser in situ keratomileusis en pacientes con defectos residuales posqueratotomía radial. MÉTODOS: Se realizó un estudio descriptivo de tipo prospectivo longitudinal a 55 ojos de 31 pacientes con miopía y/o astigmatismo residuales posqueratotomía radial reoperados con láser in situ keratomileusis en el Servicio de Cirugía Refractiva del Instituto Cubano de Oftalmología Ramón Pando Ferrer desde enero a junio del 2007. En la selección de los pacientes, se utilizaron estrictos criterios de inclusión y exclusión utilizándose las variables: error refractivo residual en equivalente esférico medio, la agudeza visual sin corrección y la mejor agudeza visual corregida preLASIK y posLASIK, así como las complicaciones transoperatorias y postoperatorias. El seguimiento promedio de los pacientes fue de 12 ± 3 meses. RESULTADOS: El equivalente esférico posLASIK disminuyó notablemente en el primer día del posoperatorio y se mantuvo estable en la última consulta. La agudeza visual sin corrección posLASIK fue 1,0 (20/20) en 22 ojos (40 por ciento) y > 0,5 (20/40) en 44 ojos (80 por ciento). En 11 ojos (20 por ciento), la mejor agudeza visual corregida mejor 1 línea en la cartilla de Snellen. Se presentó como complicación intraoperatoria un ojo con perforación central del flap corneal y dentro de las complicaciones postoperatorias se reportaron detritus y restos hemáticos en la interfase en 2 ojos, pliegues finos del colgajo en un solo ojo y epitelización de la interfase fuera del eje visual igualmente, en un solo ojo. CONCLUSIONES: El Láser in situ keratomileusis puede ser usado exitosamente en la corrección de la miopía y el astigmatismo posqueratotomía radial en casos debidamente seleccionados

OBJECTIVE: To evaluate the safety and the efficacy of the Laser in Situ Keratomileusis treatment in patients with residual defects after radial keratotomy. METHODS: A prospective, longitudinal and descriptive study was performed in 55 eyes from 31 patients with residual myopia and/or astigmatism after radial keratotomy, who were re-operated on using Laser in situ keratomileusis at Refractive Surgery Service of Ramón Pando Ferrer Cuban Institute of Ophthalmology from January to June 2007. Strict inclusion and exclusion criteria were applied to select the patients, on the basis of following variables: residual refractive errors in average spheral equivalent, visual acuity without correction and best visual acuity with correction before and after LASIK as well as the transoperative and postoperative complications. The average follow-up period were 12 ± 3 months. RESULTS: The spheral equivalent after LASIK was substantially reduced in the first day of the postoperative phase and kept stable in the last appointment with the specialist. The visual acuity without correction after LASIK was 1,0 (20/20) in 22 eyes (40 percent) and > 0,5 (20/40) in 44 eyes (80 percent). In eleven eyes (20 percent), the best corrected visual acuity improved by one line in the Snellen´s chart. The transoperative complication was found in one eye with central corneal flap perforation whereas the reported postoperative complications were detritus and hematic remains in the interphase in 2 eyes, fine foldings of the flap in one eye and epithelization of the interphase out of the visual axis also in one eye. CONCLUSIONS: The Laser in situ keratomileusis can be used successfully to correct myopia and astigmatism after radial keratotomy in duly selected cases

Intraocular Lens Power Calculation in High Myopic Eyes with Previous Radial Keratotomy

PURPOSE: To elucidate a proper method of intraocular lens (IOL) power calculation in highly myopic eyes with previous radial keratotomy (RK). METHODS: Five post-RK-surgery eyes with pre-RK-surgery myopia over -10.0 diopters (D) were studied retrospectively. The keratometric values obtained via the clinical history method, the contact lens over-refraction method, conventional keratometry, and Orbscan II were compared to the true keratometric value calculated retrospectively using the SRK/T formula. RESULTS: The mean pre-RK-surgery refractive power was -19.35+/-5.86D (-14.50 ~ -29.50D) and cataract surgery was performed on average 16.6 years after RK. The true keratometric value was closest to that estimated by the contact lens over-refraction method in 1 eye and to the flatter keratometric value between Sim K and the 3mm zone mean Pwr obtained with axial keratometric power map of Orbscan II in 4. CONCLUSIONS: The flatter keratometric value between Sim K and the 3mm zone mean Pwr from Orbscan II was closest to the true post-RK-surgery keratometric value of the central cornea.