Abstract
Abstract: :
Purpose: To determine the effect of age on the hydraulic conductivity of human lens anterior capsule. This is relevant to drug transmission, cataractogenesis and presbyopia. Methods: 18 fresh eye bank donor eyes were obtained from 18 different patients, ranging from 16–88 years with an even age distribution. Each lens was aseptically microdissected and the anterior capsule removed, inspected for damage and mounted in a ring cassette. Hydraulic conductivity was measured using a modified Ussing chamber with an associated pressure head of PBS set at normal intraocular pressure. Detailed calibration and testing of the hydraulic conductivity system with control membranes had been performed. Following conductivity assesment, the capsular specimens were embedded in araldite and processed for light microscopy. Capsular thickness was measured using a sliding graticule and the minimum reading used to correct hydraulic conductivity for unit path length. Results: Mean hydraulic conductivity of human lens anterior capsule was 1.3x10–10 ms–1Pa–1. Hydraulic conductivity showed no variation with age. However, lens anterior capsular thickness, and therefore also hydraulic conductivity per unit pathlength, were found to increased with age. Hydraulic conductivity values corresponded to the limited data in the literature but disputed previous data on age variation. Conclusions: Human lens anterior capsular hydraulic conductivity does not appear to alter with age. However, this may be the product of an increase in lens anterior capsular thickness being offset against an inherent increase in capsular hydraulic conductivity per unit pathlength.
Keywords: aging • cell membrane/membrane specializations • cataract