Development and recovery of laser-induced retinal lesion in rats.
OBJECTIVE
Laser-induced retinal lesions undergo primary and secondary degeneration followed by a partial reduction of the lesion size. To evaluate treatment effects, detailed data regarding the changes of the lesion over time are essential. The purpose of the study is to describe the histologic changes in an argon laser-induced retinal lesion over a period of 60 days.


METHODS
Argon laser lesions were produced in retinas of pigmented rats. The lesions were examined by light microscopy 1 hour and 1, 2, 3, 20, and 60 days after the exposure.


RESULTS
The diameter of the lesion increased 24 hours after photocoagulation and then decreased by day 20. Most pyknotic nuclei seen in the outer nuclear layer 1 hour after lasering disappeared 3 days later. Remodeling began 3 days after lasering. By day 60, partial filling in of the empty area with sliding of adjacent nuclei was observed. Recovery was also seen in the other retinal layers.


CONCLUSIONS
The course of a laser-induced retinal lesion is gradual: the photoreceptors are damaged first and the damage then spreads to other layers and to the adjacent retina. By day 3, the damage spreading stops, and adjacent cells begin to fill in and remodel the area of the lesion.
Belokopytov
Mark
M
Goldschleger Eye Research Institute, Sackler School of Medicine, Tel Aviv University, Sheba Medical Center, Tel Hashomer, Israel. markb120@gmail.com
Belkin
Michael
M
Dubinsky
Galina
G
Epstein
Yoram
Y
Rosner
Mordechai
M
D000818:Animals; D004195:Disease Models, Animal; D005451:Fluorescein Angiography / Q000379:methods; D007834:Lasers / Q000009:adverse effects*; D016253:Microscopy, Immunoelectron / Q000379:methods; D051381:Rats; D020127:Recovery of Function / Q000502:physiology*; D012160:Retina / Q000473:pathology / Q000648:ultrastructure; D012164:Retinal Diseases / Q000209:etiology* / Q000473:pathology / Q000503:physiopathology*; D013997:Time Factors; D041623:Tomography, Optical Coherence / Q000379:methods