Ultrastructural age-related changes on the posterior iris surface. A possible relationship to the pathogenesis of exfoliation
A. K. Khalil, T. Kubota, A. Tawara and H. Inomata
Department of Ophthalmology, Faculty of Medicine, Kyushu University, Fukuoka, Japan.
OBJECTIVES: To verify the presence of age-related changes in the human iris
and to determine whether such changes could be related to the pathogenesis
of the exfoliation syndrome. DESIGN: Ultrastructural examination of the
posterior surface of the normal iris in 9 enucleated eyes. PATIENTS OR
OTHER PARTICIPANTS: Eyes of persons aged 1 day, 3 months, and 3, 9, 27, 52,
59, 59, and 65 years. MAIN OUTCOME MEASURE: The presence of aging changes
in the iris. RESULTS: Aging changes included duplication of the basal
lamina of posterior iris pigment epithelial cells, formation of atrophic
invaginations in the posterior cell membranes containing interlacing basal
lamina, formation (or deposition) of microfibrils 11 to 13 nm in diameter,
with a banding periodicity of 12 to 16 nm, deposition of electron-dense
material in relation to the basal lamina and/or microfibrils, and the
presence of some fine granular material overlying the basal lamina.
CONCLUSION: These changes have been consistently described before in
association with exfoliation material, which suggests the possibility that
exfoliation is an eventual aging process.
