Anatomic alterations in aging and age-related diseases of the eye

Abstract

Purpose: We described anatomic age-related changes in the human eye to determine potential areas of investigation that may lead to identifying eyes at risk for age-related disease.

Methods: A descriptive review of anatomic changes in the eye related to aging was performed in the context of current areas of investigation. The review was performed specifically for differing anatomic ocular structures, including cornea, trabecular meshwork, lens, uveal tract, Bruch's membrane, retina, RPE, vitreous, sclera, and optic nerve.

Results: Age-related changes occur in all ocular tissues. The cornea flattens and there is an attrition of endothelial cells. The shape of the trabecular meshwork changes and there is a loss of trabecular endothelium. The lens grows and becomes cataractous. The ciliary body becomes collagenized, there are choroidal vascular changes, and Bruch's membrane thickens. Retinal vessels become hyalinized and there is a loss of rods before cones in the macula. RPE morphometric changes occur with aging. The vitreous becomes liquefied and there is a loss of vitreous compartmentalization. The sclera becomes rigid and may become calcified. The optic nerve exhibits structural changes with age.

Conclusions: There are numerous anatomic age-related changes in the human eye. Current areas of investigation related to these changes include adaptive optics scanning laser ophthalmoscopy imaging of the RPE mosaic in the context of aging, and drug delivery devices that overcome age-related alterations to retinal and macular perfusion.

Keywords: aging; anatomy; pathology.

Figure 1

RPE sheet mosaic in the macula. (A) Flat mount from age-matched patient without age-related macular degeneration showing compact, hexagonal cell borders. (B) Flat mount from age-matched patient with age-related macular degeneration showing considerable cell border pleomorphism and multiple nuclei per cell (ex vivo human RPE flat mounts imaged stained with fluorescent antibody for ZO1, counterstained with propidium iodine, and imaged with 488 nm excitation and 510 emission filters).

Figure 2

Age-related changes of vitreous anatomy. (A) The vitreous of a 65-year-old woman shows a premacular opening (blue arrows). Fluorescein dextran injected through the pars plana has migrated to the premacular opening (green arrow). (B) The vitreous of a 75-year-old man has collapsed, there is no visible premacular opening, and fluorescein dextran injected at the pars plana has not migrated posteriorly (ex vivo preparation of human eye bank eyes, frozen with posterior sclera dissected, and thawed).