Biometry of the Primate Lens Capsule Pre-Post Endolenticular Evacuation ex vivo

Abstract

Purpose:: To determine if the capsular bag dimensions after endolenticular evacuation can be predicted from the natural lens dimensions.

Methods:: Experiments were performed on cadaver human (n=15, 8-76 years, <5 days postmortem) and cynomolgus monkey (n=19, 5.3-14 years, <2 days postmortem) eyes. The eyes were prepared by bonding 8 PMMA segments on the sclera after removal of conjunctiva, adipose, and muscle tissues. The globe was dissected leaving a lens-zonule-ciliary body-sclera section with intact hyaloid and anterior vitreous. The section was transferred to an optomechanical lens stretcher (Parel, EVAS I, ARVO 2002). The sclera between each segment was sectioned. Digital images of the lens were recorded through an operation microscope set at 10x. A mini-capsulorhexis (< 2mm diameter) was made in the peripheral region of the capsule, the lens content was removed, and the empty capsular bag diameter was measured on recorded digital images. The diameter of the natural lens and empty bag were compared. In 12 of the 19 cyno and 7 of the 15 human lenses, the diameter and thickness of the contralateral isolated natural lens were measured by shadowphotography. The surface area of the empty capsular bag was compared with the surface area of the contralateral eye, calculated using the equation of an ellipse

Results:: The diameter of the unstretched empty capsular bag increases as a function of age in both humans and cynomolgus monkeys (p=0.10 and p=0.002, respectively). The surface area of the empty capsular bag also increases as a function of age (p=0.10 human and p=0.02 cyno). The ratio of empty capsular bag diameter to natural lens diameter is constant for both species of all ages (ratio=1.08). The ratio for empty bag surface area to natural lens surface area is also constant for both species for all ages (ratio=0.83).

Conclusions:: The empty lens capsule diameter can be predicted from normative data on intact lenses.Support: NIH EY14225; Florida Lions Eye Bank; Vision CRC, Sydney Australia;AMO Inc, Santa Ana, CA;NSF Graduate Student Fellowship; NIH center grant P30-EY014801; Research to Prevent Blindness.; Henri and Flore Lesieur Foundation.

Keywords: presbyopia • aging • anatomy