Efficacy of Preoperative Risk Stratification on Resident Phacoemulsification Surgeries.

Purpose: To evaluate efficacy of a novel risk stratification system in minimizing resident surgical complications and to evaluate whether the system could be used to safely introduce cataract surgery to earlier levels of training. Materials and Methods: This is a retrospective cross-sectional study on 530 non-consecutive cataract cases performed by residents at Columbia University. Risk scores, preoperative best corrected visual acuity (BCVA), intraoperative complications, postoperative day 1 (POD1), and month 1 (POM1) exam findings were tabulated. The relationship between risk scores and POD1 and POM1 BCVA was modeled using linear regression. The relationship between risk scores and complication rates was modeled using logistic regression. Logistic regression was used to model the rates of complications across different levels of training. Rates of complications were compared between diabetic versus non-diabetic patients using t-tests. Results: Risk scores did not have significant association with intraoperative complications. Risk scores were predictive of corneal edema (OR = 1.36, p = 0.0032) and having any POM1 complication (OR = 1.20, p = 0.034). Risk scores were predictive of POD1 (ß = 0.13, p < 0.0001) and POM1 (ß = 0.057, p = 0.00048) visual acuity. There was no significant association between level of training and rates of intraoperative (p = 0.9) or postoperative complications (p = 0.06). Rates of intraoperative complication trended higher among diabetic patients but was not statistically significant (p = 0.2). Conclusion: Higher risk scores were predictive of prolonged corneal edema but not risk of intraoperative complications. Our risk stratification system allowed us to safely introduce earlier phacoemulsification surgery.

Long-term capsule clarity with a disk-shaped intraocular lens.

PURPOSE: To evaluate long-term capsular clarity with a modified disk-shaped 1-piece hydrophilic acrylic monofocal intraocular lens (IOL) (Zephyr) suspended between 2 complete haptic rings connected by a pillar of the haptic material. SETTING: John A. Moran Eye Center, University of Utah, Salt Lake City, Utah, USA. DESIGN: Experimental study. METHODS: Study and control (1-piece hydrophobic acrylic) IOLs were implanted into the right and left eyes, respectively, of 8 New Zealand rabbits. Eyes were examined at the slitlamp at set intervals for 6 months. At the end of the clinical follow-up, the globes were enucleated and capsular clarity was scored from the posterior view (Miyake-Apple technique). Then, all the eyes were processed for a complete histopathological evaluation. RESULTS: At 6 months, the slitlamp evaluation showed a posterior capsule opacification score of 0.28 ± 0.26 (SD) in the study group and 4 ± 0 in the control (P < .0001, paired t test). The anterior capsule was generally clear in the study group. This parameter was difficult to analyze in the control group because of synechiae formation and poor pupil dilation. CONCLUSIONS: The degree of capsular bag clarity observed at 6 months postoperatively in the study eyes in this rabbit model was exceptional. It was likely because of the IOL design, keeping the capsular bag open and expanded, and minimizing contact between the IOL and the anterior capsule.

Intraocular lens power adjustment by a femtosecond laser: In vitro evaluation of power change, modulation transfer function, light transmission, and light scattering in a blue light-filtering lens.

PURPOSE: To evaluate intraocular lens (IOL) power, modulation transfer function (MTF), light transmission, and light scattering of a blue light-filtering IOL before and after power adjustment by a femtosecond laser obtained through increased hydrophilicity of targeted areas within the optic, creating the ability to build a refractive-index-shaping lens within an existing IOL. SETTING: John A. Moran Eye Center, University of Utah, Salt Lake City, Utah, USA. DESIGN: Experimental study. METHODS: Ten CT Lucia 601PY single-piece yellow hydrophobic acrylic IOLs were used in this study. The IOL power and MTF were measured with a power and modulation transfer function device. Light transmission was measured using a Lambda 35 UV-VIS spectrophotometer. Backlight scattering was assessed with a Scheimpflug camera within the IOL substance. All measurements were done with hydrated IOLs. The IOLs were also evaluated under light microscopy (LM) before and after laser adjustment. RESULTS: After laser adjustment, a mean power change of -2.037 diopters was associated with a MTF change of -0.064 and a light transmittance change of -1.4%. Backlight scattering increased within the IOL optic in the zone corresponding to the laser treatment at levels that are not expected to be clinically significant. Treated areas within the optic could be well appreciated under LM without damage to the IOLs. CONCLUSION: Power adjustment of a commercially available hydrophobic acrylic blue light-filtering IOL by a femtosecond laser produced an accurate change in dioptric power while not significantly affecting the quality of the IOL.

Biocompatibility of intraocular lens power adjustment using a femtosecond laser in a rabbit model.

PURPOSE: To evaluate the biocompatibility (uveal and capsular) of intraocular lens (IOL) power adjustment by a femtosecond laser obtained through increased hydrophilicity of targeted areas within the optic, creating the ability to build a refractive-index shaping lens within an existing IOL. SETTING: John A. Moran Eye Center, University of Utah, Salt Lake City, Utah, USA. DESIGN: Experimental study. METHODS: Six rabbits had phacoemulsification with bilateral implantation of a commercially available hydrophobic acrylic IOL. The postoperative power adjustment was performed 2 weeks after implantation in 1 eye of each rabbit. The animals were followed clinically for an additional 2 weeks and then killed humanely. Their globes were enucleated and bisected coronally just anterior to the equator for gross examination from the Miyake-Apple view to assess capsular bag opacification. After IOL explantation for power measurements, the globes were sectioned and processed for standard histopathology. RESULTS: Slitlamp examinations performed after the laser treatments showed the formation of small gas bubbles behind the lenses that disappeared within a few hours. No postoperative inflammation or toxicity was observed in the treated eyes, and postoperative outcomes and histopathological examination results were similar to those in untreated eyes. The power measurements showed that the change in power obtained was consistent and within ±0.1 diopter of the target. CONCLUSIONS: Consistent and precise power changes can be induced in the optic of commercially available IOLs in vivo by using a femtosecond laser to create a refractive-index shaping lens. The laser treatment of the IOLs was biocompatible.