Short-term effect of argon laser trabeculoplasty in monkeys
S. Melamed, J. Pei and D. L. Epstein
We performed argon laser trabeculoplasty (ALT) in four cynomolgus monkeys
and evaluated the morphologic changes in the trabecular meshwork one hour
and 14 hours following the laser treatment. One hour after ALT, disruption
of the trabecular beams and coagulative necrosis of the tissue were
evident. Fragmented cells and fibrillar tissue debris were found in the
trabecular spaces, accumulating in the juxtacanalicular region. This might
explain the elevation of intraocular pressure seen immediately following
ALT in some glaucomatous patients. Also, many trabecular endothelial cells
were rounded up, displaying different stages of leaving the beams; these
cells were actively phagocytic. Such stimulation of trabecular meshwork
cells with subsequent removal of tissue debris might explain the temporary
nature of elevation of intraocular pressure following ALT.