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.

Long-term uveal and capsular biocompatibility of a novel modular intraocular lens system.

BACKGROUND: We evaluated the long-term biocompatibility and safety of a new modular posterior chamber intraocular lens (IOL) system in rabbit eyes. METHODS: Seven New Zealand rabbits underwent bilateral phacoemulsification with placement of the modular IOL in OD and a control IOL (SA60AT) in OS. Slit-lamp examinations were performed at postoperative weeks 1, 2, 3, 4, 6 and 8 and months 3 and 6. All rabbits were then sacrificed and eyes enucleated. The eyes were examined grossly from the Miyake-Apple view. Selected IOLs were explanted and underwent surface staining for implant cytology. All globes were then sectioned and processed for histopathological examination. RESULTS: The modular IOL remained stable in all seven rabbits through the entire follow-up period. Biocompatibility was better than the control lens at six months postoperatively, on account of less extensive synechiae formation as assessed by slit-lamp examination. At the six-week examination, posterior capsule opacification (PCO) was significantly better in the test group (scored as 1.71 ± 0.8 versus 3.28 ± 0.48 in the control group, p = 0.0008). On gross examination with the Miyake-Apple view, Soemmering's ring formation was significantly better in the test group, (5.14 ± 1.57 versus 10.85 ± 1.95 in the control group, p = 0.002). CONCLUSION: Previous studies showed that explantation/exchange of the modular system optic was safer and easier than with a standard IOL. The new modular IOL system has demonstrated better long-term biocompatibility compared to the control lens at six months postoperatively in the rabbit model.

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.