Use of mini-capsulorhexis in the Phaco-Ersatz technique for cataract surgery in a rabbit model

Abstract

 

Purpose

 

To assess safety and feasibility of phacoemulsification and refilling the capsular bag with a clear polymer through a mini-capsulorhexis (MCR), followed by crosslinking the polymer in a rabbit model.

 

Methods

 

104 eyes of 86 NZW rabbits under general anesthesia were operated by four surgeons (3 in training) over an 18 month period using 4 types of polymers; a double paracentesis was performed, the anterior chamber refilled with viscoelastic, a manual MCR was performed, phacoemulsification with a 0.7mm tip, the rhexis was closed with a miniature capsulorhexis valve (MCV) (Fig 1) and subsequent injection of the polymer was performed using a curved blunt 0.55mm cannula. The clear cornea incision was closed with a single 10-0 nylon and the polymer was crosslinked. Clinical biomicroscopy, tonometry, gonioscopy and funduscopy were performed post-op in all animals at different time points and clinical data was collected.

 

Results

 

Manual MCR ranged 1.19±0.38mm. The most common complications during surgery was MCR tearing in 26 eyes (25 %), anterior capsule tearing in 8 eyes (7.69%), posterior capsule tearing in 9 eyes (8.65%) and leaking polymer during injection was observed in 22 eyes (21.15%). Postoperative clinical features observed were fibrosis around the MCR, posterior synechiae and posterior capsule opacification. In the more recent procedures refraction changes were assessed with an intraoperative autorefractometer adapted to the surgical microscope (OPMI, Fig 2).

 

Conclusions

 

Phacoemulsification through a mini-capsulorhexis is feasible and a safe technique (Fig 1). Learning curve is short. The most common complication was rhexis tearing that might be avoidable using a femto-second laser. All polymers tested were easy to inject, safe and biocompatible. Further studies are underway to assess the accuracy of intraoperative autorefractometer controlled lens refilling.

 

 

Minicapsulorrhexis Valve (MCV)

 

 

Intraoperative autorefractometer mounted onto the surgical microscope

 

Keywords: 404 accommodation • 445 cataract • 676 refraction