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

Safety, biocompatibility, and potential functionality of a new accommodative intraocular lens: An experimental study in rabbits

This study aims to evaluate the safety, biocompatibility, and functionality of a new accommodative intraocular lens (IOL) (LUZ, patent PCT/ES2016/070,813) after implantation in rabbit eyes. LUZ (Study) and EyeCee® plus a capsular ring (Control) were implanted in rabbits (n = 8 each) after phacoemulsification. Intraoperative follow-up, long-term clinical follow-up, and functional IOL studies were carried out periodically for up to 180 days. A macroscopic examination of the eyeballs to reveal abnormalities and determine the implant centering and a microscopic examination to semi-quantify cell and tissue response were performed. Statistical analysis of the collected data was finally achieved. During follow-up, no significant changes in the general condition nor the clinical evaluation were observed between both groups. However, Study IOL remained centered throughout the study and did not present severe complications as observed in the Control group. Functional studies did not reveal significant differences between both materials. Study showed better centering, fewer adhesions, and maintenance of an opening capsular bag compared to the Control. Local biological effects caused by Study implantation are minimal and comparable to the Control. Therefore, LUZ showed no clinical signs or histological response of adverse reaction to the implanted material, according to UNE-EN ISO 11979-5 and 10993-6. Functionality must be confirmed in another animal species with greater lens accommodation capacity than the rabbit. LUZ keeps the capsular bag open, favoring its centering and avoiding fibrosis and adherence to the bag; this allows potential accommodation of this IOL and theoretically enables the patient to focus dynamically.

Intraocular lens explantation following cataract surgery: Indications, techniques, and video demonstrations

As techniques for modern cataract surgery have expanded and premium intraocular lens (IOL) use is now widespread, patient expectations are high. The need for IOL explantation, whilst still low, remains an ongoing issue. Intraocular lens explantation can be challenging for a number of reasons and as such we have introduced an additional technique to add to the surgeon's repertoire. Bimanual haptic stripping of fibrosis at the specific area where the haptic is adherent to the capsular bag is an effective strategy to aid in dissection of haptics without compromising the capsule or zonules. Given the challenges associated with IOL explantation, newly designed IOLs need to avoid these "sticking points" at which the IOLs interact with the fibrosed capsule. Techniques we have evolved and which are described below should assist anterior segment surgeons to facilitate IOL removal in an efficient and safe way.

Long-term uveal and capsular biocompatibility of a new fluid-filled, modular accommodating intraocular lens

PURPOSE

To evaluate long-term uveal and capsular biocompatibility of a new fluid-filled modular accommodating intraocular lens (IOL) consisting of base and fluid lenses.

SETTING

John A. Moran Eye Center, University of Utah, Salt Lake City, UT, USA.

DESIGN

Experimental study.

METHODS

Bilateral phacoemulsification was performed on 8 rabbits; 1 eye received the test IOL (Juvene) and the other a hydrophobic acrylic control IOL (SA60AT). Slitlamp examinations were performed at postoperative weeks 1 and 4, and at months 2, 3, and 6. The rabbits were killed humanely at 6 months. After gross examination from the Miyake-Apple view, IOLs were removed for implant cytology. All globes were then processed for histopathologic examination.

RESULTS

Uveal biocompatibility was similar between test and control IOLs up to 6 months postoperatively. Anterior capsule opacification appeared absent in the test group, and posterior capsule opacification (PCO) was significantly less in comparison with the control group throughout the study. At 6 months, central PCO was scored as 0.12 ± 0.23 with test IOLs and as 4.0 ± 0 with control IOLs (P < .0001, 2-tailed t test: paired 2-sample for means). Histopathologic examination confirmed the relative lack of capsular opacification in test eyes in comparison to controls and the absence of toxicity in any eye.

CONCLUSIONS

Six weeks in the rabbit model corresponds to approximately 2 years in the human eye for PCO. In this model, the Juvene IOL maintained an open and expanded capsular bag, preventing overall capsular bag opacification while retaining excellent uveal and capsular biocompatibility.

Explantation/exchange of the components of a new fluid-filled, modular, accommodating IOL

PURPOSE

To evaluate the ease of replacement and capsular stability of a new fluid-filled, modular, accommodating intraocular lens (IOL) system composed of a monofocal base lens with a fluid lens clipped inside of it.

SETTING

John A. Moran Eye Center, University of Utah, Salt Lake City, Utah, USA.

DESIGN

Experimental study.

METHODS

Five New Zealand rabbits underwent bilateral phacoemulsification with implantation of the test lens (Juvene, LensGen, Inc.) in both eyes (4 rabbits), or a control IOL in 1 eye (AcrySof, Alcon Laboratories, Inc.) and the test IOL in the other (1 rabbit). At 2 weeks, the 4 rabbits with bilateral Juvene IOLs had the clipped-in fluid lens exchanged for a new fluid lens in 1 eye, and the base and fluid lenses exchanged for a control lens in the contralateral eye. Slitlamp examinations were performed weekly for 4 weeks. The globes were enucleated and evaluated with ultrasound biomicroscopy, grossly from the posterior Miyake-Apple view, and histopathologically.

RESULTS

Explantation/exchange of the fluid lens was considered straightforward by the surgeon. Explantation of the base lens (4) was also safely performed, albeit more demanding, without any signs of damage to the capsular bag under clinical, ultrasound biomicroscopy, and pathological examination in the exchanged eyes. Less capsular bag opacification was observed with the Juvene lens system.

CONCLUSIONS

Explantation/exchange of the fluid lens component, or both fluid and base lenses, of this new lens system can be safely accomplished if necessary, because of its modular design and the relative lack of postoperative capsular bag opacification associated with it.

Intraocular Lenses: Overview of Designs, Materials, and Pathophysiologic Features

This article provides an overview of intraocular lenses (IOLs) currently used in cataract surgery. Aspects presented include design features related to IOL construction and sites of fixation; optic, filter, and haptic materials; as well as pathophysiologic features of uveal biocompatibility, capsular biocompatibility, and postoperative IOL opacification. This overview also includes supplementary (add-on; piggyback) lenses implanted in eyes that are already pseudophakic and considerations on IOLs used in the pediatric population. Different IOLs are made available to surgeons each year, including lenses with increasingly complex design characteristics owing to advancements in manufacturing and surgical techniques.