Experimental evaluation of the Corneal Concept 360 intraocular lens with the Miyake-Apple view

Lenticular Imaging: A New Experimental and Quantitative Analysis of Capsular Dynamics, "Choi-Apple View"

Purpose

Development of a means for quantitative estimation of lenticular and zonular dynamics by using real-time imaging of human autopsy eyes during implantation of different intraocular lens (IOL) models.

Methods

Isolated lenticular structures from human autopsy eyes were prepared in vitro. The following IOLs were implanted: a one-piece C-loop haptic IOL, a three-piece C-loop haptic IOL, and a one-piece plate-type IOL. The amount of deformation of lenticular structures during implantation was calculated and the movements visualized with two cameras. The results were transformed to two-dimensional graphs using a newly developed image-processing algorithm.

Results

For both one-piece plate-type and one-piece C-loop haptic IOLs, the amount of capsular bag deformation from its initial shape was greater in the direction of posterior center of the capsule, as detected by side camera, than in the direction of the equator (or periphery), as detected by front camera. The mean peak deformation values were 51% and 36% (as measured by side and front cameras, respectively) for one-piece plate-type IOL and 25% and 20% for one-piece C-loop haptic IOL. For three-piece C-loop haptic IOL, the capsular bag distention was almost equal in both posterior and peripheral directions, with mean peak deformation values reaching 39% and 38%.

Conclusions

The new experimental means of lenticular imaging and quantified dynamics from two different angles allowed three-dimensional understanding of specific behavior of each IOL. Our model not only exposes the capsular bag for recording during implantation, but also objectively compares the individual movement values and reveals different zonular and capsular stress patterns, depending on IOL model.

Translational Relevance

The novel "Choi-Apple View" allows a three-dimensional quantitative analysis of capsular dynamics and IOL implantation behavior.

Prevention of postoperative capsular bag opacification using intraocular lenses and endocapsular devices maintaining an open or expanded capsular bag

Postoperative capsule opacification is a multifactorial physiological consequence of cataract surgery that remains the most common complication of this procedure. A literature review that included several intraocular lenses (IOLs) and endocapsular devices studied in our laboratory found that devices maintaining the capsular bag in an open or expanded state were associated with improved bag clarity. This observed effect likely occurs secondary to the complex interactions of myriad mechanisms, which include formation of a barrier to lens epithelial cell (LEC) migration, mechanical compression of residual LECs, mechanical stretch at the level of the capsule equator, maintenance of overall bag contour, and enhanced endocapsular circulation of aqueous humor. We review the designs of endocapsular devices and IOLs that minimize the degree of postoperative capsule opacification by preventing capsular bag collapse and discuss the underlying mechanisms that contribute to this phenomenon.

FINANCIAL DISCLOSURE

None of the authors has a financial or proprietary interest in any material or method mentioned.

Evaluation of long-term biocompatibility and capsular bag opacification with a new silicone-polyimide plate-type intraocular lens in the rabbit model

PURPOSE

To evaluate the long-term biocompatibility and safety of the new SC9 intraocular lens (IOL) after implantation in rabbit eyes, in accordance with the requirements of the International Organization for Standardization 11979-5, Annex G:2006(E).

SETTING

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

DESIGN

Experimental study.

METHODS

Bilateral phacoemulsification was performed on 9 New Zealand white rabbits; 1 eye received the test IOL and the contralateral eye received a commercially available plate-type silicone control IOL (AA4204VL). Two rabbits were humanely killed at 2 months and the remaining at 6 months. After gross examination of the eyes from the posterior Miyake-Apple view, select IOLs were explanted and had surface staining for implant cytology. All globes were then sectioned and processed for complete histopathologic examination.

RESULTS

Overall uveal biocompatibility was similar between the test IOLs and control IOLs throughout the study. The mean posterior capsule opacification at 6 months was 0.8 ± 0.27 (SD) in the test group and 4.0 ± 0 in the control group (P = .001, t test: paired 2-sample for means). The mean posterior synechiae formation at 6 months was 1.28 ± 1.25 in the test group and 2.71 ± 0.75 in the control group (P = .01). A histopathologic examination confirmed the relative lack of capsule opacification in the study eyes compared with the control eyes and the absence of untoward inflammatory reaction or toxicity in all eyes.

CONCLUSION

The new IOL maintained an open capsular bag secondary to its design, which appeared to prevent overall capsular bag opacification and retain uveal and capsule biocompatibility.

FINANCIAL DISCLOSURE

None of the authors has a financial or proprietary interest in any material or method mentioned.

Long-term uveal and capsular biocompatibility of a new accommodating intraocular lens

PURPOSE

To evaluate long-term uveal and capsular biocompatibility of a new accommodating intraocular lens (IOL).

SETTING

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

DESIGN

Experimental study.

METHODS

Bilateral phacoemulsification was performed in 14 rabbits; 1 eye received the accommodating IOL (Fluidvision) and the other received a hydrophobic acrylic control IOL. Slitlamp examinations were performed at postoperative weeks 1 to 4 and months 2, 3, 4, and 6. Six rabbits were humanely killed at 2 months and 8 rabbits at 6 months. After gross examination with the Miyake-Apple view, selected IOLs were removed for implant cytology. All globes were then sectioned and processed for histopathologic examination.

RESULTS

Uveal biocompatibility of study and control IOLs was similar in clinical and pathologic examinations up to 6 months postoperatively. In the study group, anterior capsule opacification appeared absent and posterior capsule opacification (PCO) was significantly less than in the control group. At the gross examination at 6 months, central PCO was 0.8 ± 0.5 (SD) in the study IOLs and 3.7 ± 0.4 in the control IOLs (P < .0001, 2-tailed paired t test). Histopathologic examination confirmed the relative lack of capsule opacification in study eyes compared with controls and the absence of untoward inflammatory reaction or toxicity in all eyes.

CONCLUSIONS

The accommodating IOL maintained an expanded capsular bag secondary to the large size of the haptic elements without significant contact with the anterior capsule. This appeared to prevent overall capsular bag opacification and to retain uveal and capsular biocompatibility.

Miyake-Apple view of inner side of sclerotomy during microincision vitrectomy surgery

PURPOSE

To examine the inner surface of the sclerotomy during microincision vitrectomy surgery by Miyake-Apple view.

METHODS

The anterior half of porcine eyes was attached to a transparent acrylic plate with cyanoacrylate glue. Then, either a 23-gauge or a 25-gauge trocar-cannula was inserted through the sclera obliquely. The inner surface of the entrance site was observed posteriorly by Miyake-Apple view. These images were compared with the endoscopic view of two patients who underwent vitreous surgery for an epiretinal membrane.

RESULTS

When the trocar-cannula was inserted obliquely, the Miyake-Apple view showed that the ciliary epithelium at the sclerotomy site was stretched. When the trocar-cannula was inserted vertically, the ciliary epithelium was folded, and the folds remained even after the trocar was removed. Vitreous strands were seen incarcerated into the sclerotomy site. In human eyes, a folding of the ciliary epithelium was not clearly seen with the endoscopic view but the incarcerated vitreous was seen.

CONCLUSION

The Miyake-Apple view provided a precise, in vivo, observation of the inner surface of the entry site. It disclosed the morphological stress on the ciliary epithelium by the sclerotomy.

Biocompatibility of intraocular lens materials

PURPOSE OF REVIEW

To provide an update on currently available materials used in the manufacture of intraocular lenses, as well as new materials under development, especially with regard to their uveal and capsular biocompatibility.

RECENT FINDINGS

The biocompatibility of intraocular lens materials should be assessed in terms of uveal biocompatibility, related to the inflammatory foreign-body reaction of the eye against the implant, as well as in terms of capsular biocompatibility, determined by the relationship of the intraocular lens with remaining lens epithelial cells within the capsular bag. This situation may result in different entities, e.g. anterior capsule opacification, interlenticular opacification (between piggyback intraocular lenses), posterior capsule opacification and lens epithelial cell ongrowth. Reports on intraocular lens opacification suggest that the potential to calcify should also be taken into consideration when evaluating the long-term biocompatibility of a new material.

SUMMARY

Intraocular lenses are being progressively implanted in much earlier stages of life (refractive lens exchange, pediatric implantation) and are expected to remain in the intraocular environment for many decades. Materials used in intraocular lens manufacture should, therefore, insure long-term uveal and capsular biocompatibility, as well as ultimate transparency after implantation.