Abstract
Abstract: :
Purpose: To examine and quantify the recovery of cones following retinal reattachment in an animal model system. Methods: Experimental retinal detachments were created in the upper hemispheres of the right eyes of 2 adult cats. Three days later the retinas were surgically reattached and allowed to recover for 28 days. The posterior half of each eye was fixed in buffered 4% paraformaldehyde. Retinal wholemounts were labled with cone opsin antibodies (gifts of J. Nathans) and the biotinylated lectin, PNA, and mounted on glass slides, photoreceptor side up. Multiple sample areas across the wholemounts were digitally photographed by fluorescence microscopy. Labeled cells were counted manually and local densities determined. Patterns of these densities were compared to those previously reported in both normal and detached retinas (Linberg et al., J. Comp. Neurol. 430: 343-356, 2001). Results: A uniform field of PNA-positive cone sheaths was seen across the retina. Non-detached sample areas had normal sheath densities, while those in the periphery of reattached retina were 15 to 30% lower than normal. The greatest loss occurred in regions of highest detachment. Near the area centralis the density of cone sheaths was only about 50% of normal. S-cone labeling in non-detached areas showed normal isodensity contours. In the experimental regions, S-cone labeling was punctate, patchy and invariably of much lower density than normal, ranging from 5 to 35%, although there were scattered areas with densities over 50% of normal values. Conclusions: It is well known that deficiencies in cone-based vision (e.g., acuity, color discrimination) are an important complication of retinal detachment. In this study, a detachment of only 3 days followed by 28 days of reattachment leads to the recovery of 50 to 85% of PNA labeled cone matrix sheaths and presumably, cone OS. While this is a significant increase from 3 days of detachment when these sheaths are sparse, it may have significant effects on visual recovery. Based on the presence of anti-S-cone opsin labeling, either S-cone recovery is very limited, or severly lags behind that for the cone matrix sheaths.
Keywords: 563 retinal detachment • 517 photoreceptors • 434 immunohistochemistry