Early changes in iris blood vessels in exfoliation syndrome

To look for possible changes in iris blood vessels that might precede the formation of true exfoliation material, and to correlate these changes, if present, to aging of the iris.

Iris blood vessels of 10 clinically normal irises from 10 eyes (ages: 1 day-80 years), 4 irises with exfoliation (ages: 64-80 years) and 3 irises from primary open-angle glaucoma (POAG) (ages: 27-65 years) were examined with an electron microscope.

Pronounced multilayering of the basal lamina around the vessels, abnormal excessive formation of microfibrils, presence of atrophic invaginations in the outer cell membranes of endothelial cells containing interlacing basal lamina, and an apparent decrease in the perivascular collagen fibers were evident in exfoliative iris vessels devoid of true exfoliation material. Similar, but much milder, changes were evident in normal aged and POAG irises.

Abnormal elastic tissue and/or basal lamina production plays a role early in the formation of exfoliation material around iris blood vessels.