Comparison of Biometry Measurements Using Standard Partial Coherence Interferometry versus New Scheimpflug Tomography with Integrated Axial Length Capability.

PURPOSE: To compare biometry measurements obtained by a partial interferometer biometer (IOLMaster 500) to the new Scheimpflug tomography with an integrated axial length biometer module (Pentacam AXL). PATIENTS AND METHODS: Cataract patients who underwent biometric measurements with the IOL Master 500 and the Pentacam AXL from July to November 2017 were enrolled in this study. Comparisons were performed for axial length (AL), keratometry (K), and anterior chamber depth (ACD). The Pearson correlation coefficient and the 95% limits of agreement (LoA) were calculated. Paired Student's t-tests and Bland-Altman plots were used to assess the differences between devices. RESULTS: One hundred and sixty-six eyes of 92 patients were analyzed. There were no statistically significant differences in AL (p=0.558) or flat K (p=0.196) values between the IOL Master 500 and Pentacam AXL measurements. Statistically significant differences were found between the two devices with respect to steep K, ACD, and mean K measurements (p<0.001). CONCLUSION: Both devices provided similar measurements of AL and flat K, though there were statistically significant differences in ACD, steep K, and mean K measurements.

Objective evaluation of vision quality in pseudophakic patients with posterior capsular opacification using double-pass retinal imaging / Avaliação objetiva da qualidade da visão em pacientes pseudofácicos com opacificação capsular posterior pelo método de dupla passagem de luz

ABSTRACT Purpose: The purpose of this study was to objectively assess the optical vision quality of patients before and after Nd:YAG capsulotomy for posterior capsular opacification using a double-pass retinal imaging system. Methods: We retrospectively analyzed the data from 26 pseudophakic eyes with posterior capsular opacification that underwent Nd:YAG capsulotomy. The objective scatter indices, modulation transfer function cutoff frequencies, Strehl ratios, and logMAR corrected distance visual acuities were assessed before and after YAG capsulotomy with a double-pass retinal imaging system (OQAS II, Visiometrics, Spain). We also analyzed data from a subgroup of 10 patients with pre-YAG corrected distance visual acuity of 0.10 logMAR (20/25) or better. Results: Vision quality indices improved in all 26 eyes, resulting in a statistically significant improvement in the corrected distance visual acuity (p=0.007), objective scatter index (p=0.001), modulation transfer function cutoff frequency (p=0.001), and Strehl ratio (p=0.020). The overall mean improvements included 0.12 ± 0.04 logMAR for corrected distance visual acuity, 2.84 ± 0.76 for objective scatter index, 12.29 ± 2.77 for modulation transfer function cutoff frequency, and 0.06 ± 0.03 for Strehl ratio. Our sub-analysis of 10 eyes with 0.10 logMAR (20/25) corrected distance visual acuity or better also showed a statistically significant improvement in the mean objective scatter index (0.76 ± 16; p=0.001), resulting in approximately 35% decrease in intraocular light scatter. Conclusions: The objective vision quality measurements as assessed by the double-pass retinal imaging system showed a significant improvement after YAG capsulotomy. This suggests that the objective scatter index improves after YAG capsulotomy, even in eyes with pre-YAG 0.10 logMAR (Snellen 20/25) corrected distance visual acuity or better.

RESUMO Objetivo: Avaliar objetivamente a qualidade da visão óptica antes e depois da capsulotomia com Nd: YAG, obtida por imagem pelo metodo de dupla passagem de luz em pacientes com opacificação capsular posterior. Método: Análise retrospectiva de 26 olhos pseudofácicos com opacificação capsular posterior visualmente significativa, que foram submetidos à capsulotomia de Nd: YAG. O índice de dispersão objetiva, a função de transferência de modulação, a relação de Strehl e a acuidade visual à distância corrigida foram avaliados antes e após a capsulotomia com YAG usando o dupla passagem de luz (OQAS II, Visiometrics, Espanha). Também foi analisado um subgrupo de pacientes com acuidade visual à distância corrigida pré-YAG de 0,10 logMAR (20/25) ou melhor. Resultados: Os índices de qualidade da visão melhoraram em todos os 26 olhos, resultando em uma melhora estatisticamente significativa na acuidade visual à distância corrigida (p=0,007), índice de dispersão objetiva (p=0,001), função de transferência de modulação (p=0,001) e relação de Strehl (p=0,020). A melhora média na acuidade visual à distância corrigida foi de 0,12 ± 0,04 logMAR, no índice de dispersão objetiva foi de 2,84 ± 0,76, no função de transferência de modulação foi de 12,29 ± 2,77 e na razão de Strehl foi de 0,06 ± 0,03 em todos os olhos. Sub-análise de 10 olhos com 0.10 logMAR (20/25) acuidade visual à distância corrigida ou melhor também mostrou uma melhora estatisticamente significativa no índice de dispersão objetiva (p=0,001). A melhora média no OSI foi de 0,76 ± 16, uma diminuição de 35% na dispersão da luz intraocular. Conclusões: A qualidade da visão avaliada pelo dupla passagem de luz mostra uma melhora significativa nas medidas objetivas da qualidade da visão após a capsulotomia do YAG. O índice de dispersão objetiva melhora após a capsulotomia YAG, mesmo em olhos com acuidade visual à distância corrigida pré-YAG de 0,10 logMAR (Snellen 20/25) ou melhor.

Objective evaluation of vision quality in pseudophakic patients with posterior capsular opacification using double-pass retinal imaging.

PURPOSE: The purpose of this study was to objectively assess the optical vision quality of patients before and after Nd:YAG capsulotomy for posterior capsular opacification using a double-pass retinal imaging system. METHODS: We retrospectively analyzed the data from 26 pseudophakic eyes with posterior capsular opacification that underwent Nd:YAG capsulotomy. The objective scatter indices, modulation transfer function cutoff frequencies, Strehl ratios, and logMAR corrected distance visual acuities were assessed before and after YAG capsulotomy with a double-pass retinal imaging system (OQAS II, Visiometrics, Spain). We also analyzed data from a subgroup of 10 patients with pre-YAG corrected distance visual acuity of 0.10 logMAR (20/25) or better. RESULTS: Vision quality indices improved in all 26 eyes, resulting in a statistically significant improvement in the corrected distance visual acuity (p=0.007), objective scatter index (p=0.001), modulation transfer function cutoff frequency (p=0.001), and Strehl ratio (p=0.020). The overall mean improvements included 0.12 ± 0.04 logMAR for corrected distance visual acuity, 2.84 ± 0.76 for objective scatter index, 12.29 ± 2.77 for modulation transfer function cutoff frequency, and 0.06 ± 0.03 for Strehl ratio. Our sub-analysis of 10 eyes with 0.10 logMAR (20/25) corrected distance visual acuity or better also showed a statistically significant improvement in the mean objective scatter index (0.76 ± 16; p=0.001), resulting in approximately 35% decrease in intraocular light scatter. CONCLUSIONS: The objective vision quality measurements as assessed by the double-pass retinal imaging system showed a significant improvement after YAG capsulotomy. This suggests that the objective scatter index improves after YAG capsulotomy, even in eyes with pre-YAG 0.10 logMAR (Snellen 20/25) corrected distance visual acuity or better.

Emerging Technology in Refractive Cataract Surgery.

Technology in cataract surgery is constantly evolving to meet the goals of both surgeons and patients. Recent major advances in refractive cataract surgery include innovations in preoperative and intraoperative diagnostics, femtosecond laser-assisted cataract surgery (FLACS), and a new generation of intraocular lenses (IOLs). This paper presents the latest technologies in each of these major categories and discusses how these contributions serve to improve cataract surgery outcomes in a safe, effective, and predictable manner.

Corneal cross-linking: engineering a predictable model.

Corneal collagen cross-linking (CXL) with riboflavin and ultraviolet-A (UVA) light has become a viable treatment for keratoconus. In cases in which corneal transplant may have previously been a patient's primary treatment option, the results of CXL have varied from decreased progression of the disease to marked regression characterized by improvement in visual acuity. In addition, changes to the original protocol have been tested that include leaving the epithelium intact and increasing the UVA intensity while decreasing the exposure time. The variation in results and protocols underscores the need for a greater understanding of the procedure and its effects. Ideally, a complete definition of the effects of CXL will lead to patient-specific treatment through highly controlled delivery methods of riboflavin and UVA light and complete mathematical models for predicting the final shape and refractive effect of the cornea. Thus, in this review, we aimed to describe the current techniques for measuring the effect of CXL, with a focus on material property changes, while highlighting the challenge of engineering a predictable mathematical model of the procedure and the resulting clinical outcome.