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February 1979

Echothiophate Cataracts in Monkeys: Electron Microscopy and Microradiography

Arch Ophthalmol. 1979;97(2):340-346. doi:10.1001/archopht.1979.01020010186023

• Anterior and posterior subcapsular cataracts were induced in cynomolgus monkeys by topical treatment with echothiophate iodide. The lenses were then studied by light and electron microscopy and by quantitative microradiography. Microradiography revealed foci of swollen lens fibers and reduced protein concentration in the anterior-most and posterior-most 0.3 mm of cortex. By electron microscopy, focal areas of the lens epithelium and the anterior and posterior subcapsular cortex demonstrated enlarged intercellular spaces containing cell membrane fragments and amorphous material. The cortical abnormalities were most frequent at or near the lens sutures. The microradiographic and electron microscopic abnormalities in the cortex corresponded in location, distribution, and optical properties to the vacuoles and solid-appearing opacities seen biomicroscopically in vivo. The mechanism for the increased hydration of the lens caused by cholinesterase inhibitors remains unknown.