Author(s): Lütjen-Drecoll E, Kaufman PL, Eichhorn M. Long-term timolol and epinephrine in monkeys. I. Functional morphology of the ciliary processes. Trans Ophthalmol Soc U K. 1986;105 ( Pt 2):180-95.
Journal: Transactions Of The Ophthalmological Societies Of The United Kingdom, Volume 105 ( Pt 2), 1986
Cynomolgus monkeys were treated twice daily in one eye with timolol 180 micrograms for 2.7, 6.0, or 7.4 months (2 monkeys for each period) or epinephrine 540-600 micrograms for 6.7 months (2 monkeys). Some ciliary processes in both eyes of all timolol-treated monkeys exhibited light and electron microscopic changes consistent with decreased secretion: narrowed stromal vessels with few fenestrations surrounded by a thickened fibre sheath; thickened PE basement membrane; few PE and NPE basolateral infoldings; flattened NPE with small mitochondria. Additionally, the NPE contained pigment granules and large phagolysosomes. The processes in both eyes of the epinephrine-treated monkeys exhibited one of two pictures: dilated stromal capillaries with numerous fenestrations; normal stroma, PE basement membrane and PE; numerous well-developed NPE basolateral infoldings and enlarged mitochondria; dilated stromal capillaries with ruptured fenestrations; ballooned protein-filled stroma; degenerated NPE. The first picture could be consistent with hypersecretion, the second with hyposecretion. Possible pathophysiological explanations and implications of these findings are discussed.