Irregular retinal and RPE damage after pressure-induced ischemia in the rabbit.
OBJECTIVE
Pressure-induced ocular ischemia is a frequent model for the investigation of the mechanisms and therapy of retinal ischemic damage. It is important to know whether the tissue damage in such experiments is uniform or irregular.


METHODS
We reviewed histologic features of Dutch rabbit eyes after 60-80 min of pressure-induced ischemia. The eyes were enucleated 4 hr, 1 day, or 1 wk after circulation was restored, at which times the electroretinogram b-wave was moderately reduced.


RESULTS
Light microscopy showed an irregular distribution of damage involving all retinal layers and retinal pigment epithelium. Some regions of damage (or preservation) were several millimeters wide; others were as small as a few cell widths. Correlation with electroretinogram reduction in individual eyes was difficult.


CONCLUSIONS
These results show that pressure-induced ischemic damage in the rabbit, sufficient to reduce the electroretinogram, has a patchy and irregular effect on retina and retinal pigment epithelium. Erroneous judgments may be made about ischemic damage, or therapeutic intervention, if only small or selected regions of retina are examined histologically.
Marmor
M F
MF
Department of Ophthalmology, Stanford University School of Medicine, California 94305-5308.
Dalal
R
R
D000818:Animals; D004195:Disease Models, Animal; D004596:Electroretinography; D007429:Intraocular Pressure; D007511:Ischemia / Q000473:pathology* / Q000503:physiopathology; D009798:Ocular Hypertension / Q000150:complications; D010857:Pigment Epithelium of Eye / Q000648:ultrastructure; D011817:Rabbits; D012160:Retina / Q000648:ultrastructure*; D012171:Retinal Vessels / Q000473:pathology* / Q000503:physiopathology