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

Clinical experience with adjustable scleral lenses / Experiência clínica com lentes esclerais ajustáveis

ABSTRACT Purpose: The aim of this study was to evaluate the fitting process of a scleral lens that allows several parameter adjustments during trials and after the initial period of use. In addition, we verified which adjustments were needed and used the most, their indications, and how often these resources were used, and checked the results. Methods: Scleral contact lens fittings in a private clinic setting were prospectively analyzed in a sequential, non-randomized, and non-comparative manner. All the patients underwent a complete ophthalmic examination and had an indication for scleral lens use (Zenlens, Alden Optical). Results: Scleral fit was analyzed in 80 eyes of 45 patients. Regarding diagnosis, 72% of the patients had keratoconus; 12%, radial keratotomy; 5%, post-refractive surgery ectasia; 5%, dry eye; and 3%, high myopia. In 66 (82.5%) of the 80 eyes studied, parameters were modified when the lenses were ordered. The reasons that led to the modifications were apical touch or decreased sagittal height, increased sagittal height, cylindrical over-refraction, poor visual acuity, lens flexure, peripheral touch, 360° edge compression, horizontal edge compression, and vertical edge compression. Conclusion: In this study, the use of Zenlens scleral lenses was shown to be a promising corrective treatment for patients requiring the use of scleral lenses. Although the study suggests a learning curve, as many adjustments were allowed, the lens could be customized according to the patients' needs. This increased the success rates of fitting and wearing, and consequently, use of the lens became a great option for the visual rehabilitation of patients.

RESUMO Objetivo: Avaliar o processo de adaptação de uma lente escleral que permite vários ajustes de parâmetros durante os testes e após o período inicial do seu uso; verificar quais os ajustes foram necessários, quais foram os mais utilizados, as suas indicações, a frequência com que estes recursos foram utilizados, e avaliar os resultados das mudanças realizadas. Métodos: A adaptação da lente de contato escleral foi analisada prospectivamente, de forma sequencial, não aleatória e não comparativa. Todos os pacientes foram submetidos a um exame oftalmológico completo e tinham indicação para o uso de lentes esclerais. Foi utilizada a lente Zenlens (Alden Optical). Resultados: Foi analisada a adaptação de lentes de contato esclerais em 80 olhos de 45 pacientes. Quanto ao diagnóstico, 72% tinham ceratocone, 12% tinham sido submetidos a ceratotomia radial, 5% tinham ectasia pós-cirurgia refrativa, 5% tinham olho seco, e 3%, alta miopia. Em 66 dos 80 olhos estudados (82,5%), os parâmetros foram modificados quando as lentes foram encomendadas. As razões foram: toque apical ou diminuição da altura sagital, aumento da altura sagital, sobre-refração cilíndrica, baixa acuidade visual, flexão da lente, toque periférico, compressão da borda em 360° e compressão da borda horizontal e/ou vertical. Conclusão: O uso de lentes esclerais Zenlens demonstrou ser uma forma de correção muito promissora para os pacientes que requerem o uso de lentes esclerais. Embora o estudo sugira uma curva de aprendizagem, é possível personalizar as lentes de acordo com as necessidades de cada pacientes. Este fato melhora a adaptação e aumenta a chance de sucesso do uso.

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.

Distrofia corneal de Meesmann en paciente con queratotomía hexagonal / Meesmann corneal dystrophy in a patient with hexagonal keratotomy

RESUMEN Las distrofias corneales constituyen un grupo de enfermedades hereditarias que suelen ser bilaterales y simétricas, las cuales progresan lentamente y sin relación con factores ambientales o sistémicos. Se presenta una paciente de raza blanca, de 45 años de edad, remitida al Servicio de Córnea del Instituto Cubano de Oftalmología "Ramón Pando Ferrer", quien refirió sensación de cuerpo extraño, sensibilidad a la luz y mala visión de ambos ojos, así como antecedente de queratotomía hexagonal hacía aproximadamente 20 años. En lámpara de hendidura se observaron en el epitelio numerosas lesiones puntiformes en forma de vesículas claras, semejantes a ampollas, distribuidas paracentralmente, que respetaban ligeramente el centro, con espacios de córnea transparente entre ellas y mejor visibilidad de las lesiones en retroiluminación. En la microscopia confocal se observaron en el ojo derecho estructuras redondas u ovales, de forma quística, hiporreflectivas. En el ojo izquierdo se encontraron imágenes difusas hiperreflectivas en el epitelio corneal basal. Se detectó la presencia de nervios corneales tortuosos, de aspecto fragmentado en ambos ojos. Se consideró como diagnóstico la distrofia de Meesmann y se realizó queratectomía superficial, con lo cual se logró alivio de la sintomatología de la paciente(AU)

ABSTRACT Corneal dystrophies are a group of hereditary diseases often bilateral and symmetrical which progress slowly and without any relationship to environmental or systemic factors. A case is presented of a white 45-year-old female patient referred to the Cornea Service of Ramón Pando Ferrer Cuban Institute of Ophthalmology, who reported a foreign body sensation, light sensitivity and poor vision in both eyes, as well as a history of hexagonal keratotomy from approximately 20 years before. Slit lamp examination revealed numerous punctiform lesions in the form of clear blister-like vesicles distributed paracentrally and slightly sparing the center, with transparent cornea spaces between them and better visibility of the lesions under retroillumination. Confocal microscopy showed round or oval cystic and hyporeflective structures in the right eye, whereas the left eye exhibited diffuse hyperreflective images in the basal corneal epithelium. Tortuous corneal nerves of a fragmented appearance were detected in both eyes. A Meesmann dystrophy diagnosis was considered and superficial keratectomy was performed, with which the patient's symptoms were relieved(AU)

Arcuate keratotomy infiltration following uneventful femtosecond laser assisted cataract surgery

An 84-year-old gentleman underwent uneventful femtolaser-assisted cataract surgery (FLACS) with an arcuate keratotomy (AK) in the left eye. On the 18th post-operative day, a corneal infiltrate developed involving the AK. Staphylococcus epidermidis was the organism isolated on culture. The infiltrate resolved with topical fortified vancomycin and amikacin eyedrops, and the patient regained a visual acuity of 6/6 after 12 weeks. This is the first case from south-east Asia reported in the literature of an infective infiltrate along a femtosecond laser AK. We propose strict peri-operative recommendations to be followed to prevent and treat such infections.

Long-term Results of Arcuate Keratotomy in Femtosecond Laser-assisted Cataract Surgery

PURPOSE: To investigate the long-term follow-up results of arcuate keratotomy in femtosecond laser-assisted cataract surgery. METHODS: The medical records of 78 patients (99 eyes) with corneal astigmatism >0.5 diopters (D) who underwent arcuate keratotomy concurrent with femtosecond laser-assisted cataract surgery were retrospectively reviewed. Uncorrected and corrected visual acuities and keratometric and higher order aberration outcomes were compared preoperatively and 2 years postoperatively. RESULTS: The mean uncorrected visual acuities and corrected visual acuities changed from 0.55 ± 0.31 D and 0.33 ± 0.26 D, preoperatively to 0.13 ± 0.19 D and 0.07 ± 0.09 D, 2 years postoperatively. The mean preoperative corneal astigmatism was −1.15 ± 0.66 D. This was reduced to −0.79 ± 0.38 D at 1–2 days after surgery (p < 0.001), followed by no significant change for 2 years. The mean target-induced astigmatism was 1.15 ± 0.66 D preoperatively, and the mean surgically-induced astigmatism and difference vector were 0.69 ± 0.43 D and 0.83 ± 0.48 D, 2 years postoperatively. The mean correction index was 0.68 ± 0.45, 2 years postoperatively. There was no significant difference in higher order aberrations except 4 mm and 6 mm total higher order aberrations and 6 mm trefoil between preoperatively and 2 years postoperatively. CONCLUSIONS: Arcuate keratotomy concurrent with femtosecond laser-assisted cataract surgery is a safe and effective way to reduce corneal astigmatism which remained stable over 2 years of follow-up with below moderate astigmatism.

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.

Research progress of correcting corneal astigmatism in cataract surgery / 中华实验眼科杂志

Correction of astigmatism is an important part of refractive cataract surgery.Currently,methods of combined corneal astigmatism correction in cataract surgery mainly include keratotomy and Toric intraocular lens (IOL) implantation.Whether it is a scalpel or femtosecond laser keratotomy,the effects of astigmatism correction is related to the position,shape,length and depth of the incisions,configuration,and distance between incisions and optic axis.Moreover,the pattern and material of Toric IOL can affect its rotation stability and effects of astigmatism correction.This article reviewed recent progress of correcting corneal astigmatism in cataract surgery,which provided reference for ophthalmologists in clinical.

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.

Opción terapéutica para la apertura de incisiones corneales posqueratotomías / Therapeutic option for opening of post-keratotomy corneal incisions

La cirugía refractiva incisional ha mostrado a lo largo de los años resultados impredecibles y fluctuantes. Se ha apreciado hipercorrección y astigmatismo no convencional en un número elevado de pacientes. Se presentan dos casos de ectasia corneal posquirúrgica, quienes refirieron empeoramiento progresivo de la visión. Al examen biomicroscópico se apreció apertura a nivel de las incisiones corneales por queratotomía radial y arcuata. Se muestran los resultados refractivos obtenidos en la corrección de dicha complicación mediante la utilización de suturas corneales. Se concluye que esta técnica induce resultados satisfactorios que deberíamos evaluar con certeza en el seguimiento posoperatorio de los casos(AU)

ABSTRACT Incisional refractive surgery has shown fluctuating and unpredictable results throughout the years. Hypercorrection and unconventional astigmatism have been observed in a high number of patients. Here are two patients with postsurgical corneal ectasia, who reported progressive worsening of vision. When making the biomicroscopic examination, it was observed that there was an opening at the level of corneal incisions through radial and arcuate ketatotomy. This study showed the refractive results achieved in the correction of this complication by using corneal sutures. It was concluded that this technique leads to satisfactory results that we should evaluate with certainty in the postoperative follow-up of patients(AU)

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.

Short-term Clinical Outcomes of Implantable Collamer Lens Implantation with Simultaneous Full Thickness Astigmatic Keratotomy

PURPOSE: To evaluate the clinical outcomes of implantable collamer lens (ICL) implantation with simultaneous full thickness astigmatic keratotomy (FTAK) for the correction of moderate to high myopic astigmatism. METHODS: Thirty-two eyes of 16 patients who had an ICL implantation with simultaneous FTAK were studied. Follow-up visits were at 1 week, 1 month, and 3 months. The outcome measures included the uncorrected distance visual acuity (UDVA), refractive error, efficacy, safety, and predictability. RESULTS: After the surgery, astigmatism was reduced by 74.83 ± 13.8%. The proportion of eyes with a spherical equivalent of 0.5 D or less was 87.5%, and all eyes had a spherical equivalent of 1.0 D or less at 3 months after the surgery. The proportion of eyes with a UDVA of 20/25 or better was 100%, and 20/20 or better was 81.25%. Reoperation was needed in one case (3.1%) because of undercorrection of the astigmatism, and no complications were observed. CONCLUSIONS: This study showed that ICL implantation with simultaneous FTAK is effective and safe for the correction of moderate to high myopic astigmatism.

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.

Clinical Outcomes of Combined Procedure of Astigmatic Keratotomy and Laser in situ Keratomileusis

PURPOSE: To evaluate the clinical outcomes of a combined procedure of astigmatic keratotomy (AK) and laser in situ keratomileusis (LASIK) for the correction of high astigmatism. METHODS: Thirty-five eyes of 19 patients who had astigmatic keratotomy were studied. The patients had a secondary procedure, LASIK, to correct the residual refractive error. Follow-up visits were at 1 week, 1 month, 3 months, and 6 months. The outcome measures included uncorrected distance visual acuity, refractive error, efficacy, safety, and predictability. We compared preoperative and post-AK expected corneal ablation depth using an Amaris Ablation depth table. RESULTS: After astigmatic keratotomy, astigmatism was reduced by 61.43 ± 14.62%, and after LASIK, astigmatism was reduced by 91.65 ± 8.68%. Expected corneal ablation depth was reduced by 18.72 ± 11.77% after astigmatic keratotomy. The proportion of eyes with spherical equivalent 0.5 D or less was 85.71% at 6 months after the combined procedure of astigmatic keratotomy and LASIK. No intraoperative or postoperative complications were observed. CONCLUSIONS: This study showed the combined procedure of astigmatic keratotomy and LASIK is effective for visual acuity, refraction, and reduction in corneal ablation depth.

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.

Clinical Outcomes of Beveled, Full Thickness Astigmatic Keratotomy

PURPOSE: To evaluate the beveled, full thickness astigmatic keratotomy. METHODS: This study included 185 eyes of 112 patients treated with beveled, full thickness astigmatic keratotomy. Treated eyes were divided into 3 groups: beveled, full thickness astigmatic keratotomy after implantable collamer lens (ICL) implantation (group A), beveled, full thickness astigmatic keratotomy after cataract surgery (group B) and beveled, full thickness astigmatic keratotomy alone (group C). Follow-up visits were at 1 week, 1 month, 3 months and 6 months. The outcome measures included uncorrected distance visual acuity, astigmatism, efficacy, safety and predictability. RESULTS: At 6 months postoperatively, astigmatism was significantly reduced: 68.9 +/- 18.24% in total, 69.24 +/- 20.76%, in the group A, 67.84 +/- 17.56% in the group B and 67.82 +/- 13.97% in the group C. The proportion of eyes with astigmatism 1.0 or less was 88.65% in total, 91.49% in the group A, 87.5% in the group B and 70.0% in the group C. Mean improvement in corrected distance visual acuity (CDVA) was 0.56 lines; no eyes lost 2 lines of CDVA after 6 months postoperatively. Postoperative complications were not observed. CONCLUSIONS: This study showed the beveled, full thickness astigmatic keratotomy is effective and safe for correcting astigmatism alone as well as correcting astigmatism after ICL implantation or cataract surgery.