CLINICOPATHOLOGICAL CORRELATION OF LOCALIZED RETINAL-PIGMENT EPITHELIUM DEBRIDEMENT

Purpose. To characterize changes in the retina, retinal pigment epithe lium (RPE), and choriocapillaris with fluorescein angiography (FA) and histology after hydraulic or abrasive RPE debridement in 26 domestic short-haired cats. Methods. Hydraulic debridement was produced by inje cting balanced salt solution forcefully into the subretinal space. For abrasive debridement, RPE were removed with a silicone-tipped cannula after creating a localized retinal detachment. The FAs were performed after surgery, and tissue was prepared for light microscopy (LM) and scanning electron microscopy (SEM). Results. Sixty-seven blebs were ex amined by FA 1 hour after surgery, and RPE debridement was confirmed b y SEM or LM in 15 blebs from 10 animals. Hyperfluorescence and variabl e central fluorescein leakage were seen 1 week after surgery in 52 of 53 blebs (which includes all 27 blebs from the 1-week timepoint and 26 of 29 blebs from the 4-week timepoint that were studied by FA 1 week after surgery). Choriocapillary filling delays were seen in no hydraul ic debridements, but in 11 of 14 abrasive blebs, especially in areas s howing leakage late in the angiogram. In 1 of 13 hydraulic and 12 of 1 4 abrasive debridements, areas of late dye leakage had no RPE with out er retinal degeneration. At the 4-week timepoint, 1 of 17 hydraulic an d 10 of 12 abrasive debridements had foci of delayed or absent chorioc apillary perfusion by FA, with degenerated outer retina, no RPE, and c horiocapillary atrophy by histologic analysis. Conclusions. Abrasive d ebridement is more commonly associated with abnormal FAs and with inco mplete RPE repopulation, choriocapillaris atrophy, and outer retinal d egeneration than is hydraulic debridement. This clinicopathologic stud y may give insight into FA interpretation after choroidal neovascular membrane removal in human patients.