Purchase this article with an account.
A.A. Hussain, W. Chan, J. Marshall; Laser Sub–Fractionation to Assess the Elasticity of Ageing Human Bruch’s Membrane: Reversal Implications for AMD . Invest. Ophthalmol. Vis. Sci. 2006;47(13):2317.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
To determine the relative contribution of Bruch’s to the experimentally determined elasticity of the intact ageing Bruch’s–choroid complex. To assess the potential for improving the elasticity of aged Bruch’s using various cross–link breakers.
The elasticity of the Bruch’s–choroid complex was determined in 33 donors (age range 12–97 years) using an OCT–based imaging technique. Briefly, a Bruch’s–choroid preparation was clamped in an open Ussing chamber and the cross–sectional outline of Bruch’s was captured by the OCT. The increase in arc–length of the preparation in response to applied hydrostatic pressures in the range 500–3000 Pa allowed the calculation of the elasticity index (mm/Pa)of the sample. Five of these samples (donor ages, 22, 42, 64, 82 & 90 years) were fractionated with an excimer laser to remove Bruch’s membrane and the elasticity of the remaining choroid determined. Thirteen donor samples (age range 12–90 years) were incubated with the AGE–cross link breaker, phenacylthiazolium bromide, and effects on elasticity evaluated.
The elasticity of the intact Bruch’s–choroid complex decreased with ageing of donor (p<0.001). Excimer–mediated removal of Bruch’s in five donor samples was associated with a 20–fold increase in the elasticity of the remaining choroid (elastic index 1.04 ± 0.26 mm/Pa for intact complex versus 20.4 ± 12.1 mm/Pa for choroidal mass). Incubation of intact samples with cross–link breakers was associated with a significant improvement in elasticity (p<0.005).
Despite its thinness, Bruch’s membrane was found to be the primary determinant of the elasticity of the Bruch’s–choroid complex. The age–related demise in elasticity has ramifications for transport processes across Bruch’s that are facilitated by choroidal compression–decompression cycles. The implications of greater rigidity of Bruch’s in advanced ageing such as AMD and potential for reversal as an adjunct for therapy will be discussed.
This PDF is available to Subscribers Only