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August 1995

Efficacy of Equator Rings in an Experimental Rabbit Study

Author Affiliations

From the Hara Eye Hospital, Utsunomiya (Drs Tsutomu Hara and Takako Hara), and Menicon Inc, Nagoya, Japan (Mr Sakanishi and Dr Yamada).

Arch Ophthalmol. 1995;113(8):1060-1065. doi:10.1001/archopht.1995.01100080112038

Objective:  To determine the efficacy of the equator ring in maintaining the circular contour of the capsule bag equator and transparency of the posterior capsule after crystalline lens extraction in 12 rabbit eyes.

Methods:  After phacoemulsification through a 5-mm window made by continuous circular capsulorrhexis in the central anterior capsule, a flexible silicone ring (outer diameter, 11.0 mm; width, 1.5 mm; and thickness, 1.5 mm) was implanted in the capsule in seven rabbit eyes. A 13.0-mm Sinskey-style posterior chamber intraocular lens was then implanted inside the ring. Three other eyes received only equator rings, and two others received only intraocular lenses. Eyes were followed up for 3.5±1.4 months (mean±SD) before enucleation and evaluation by stereomicroscopy; they then underwent light microscopic examination.

Results:  The two eyes that received only the intraocular lens had equatorial distortion and severe posterior capsule opacification. In nine (90%) of the 10 eyes that were implanted with the rings, the circular contour of the equator was preserved, and seven (70%) of these 10 eyes had transparent posterior capsules.

Conclusion:  Implantation of the equator ring effectively maintained the circular contour of the capsule bag equator and inhibited cells at the bag equator from proliferating toward the center of the posterior capsule in the rabbit.