Immunocytochemical characterization of macular hole opercula.

OBJECTIVES To immunocytochemically characterize the neural and glial elements of idiopathic full-thickness macular hole (FTMH) opercula excised during vitrectomy, and to correlate them with the outcome of surgery. METHODS Opercula were collected from eyes undergoing vitrectomy for stage 3 FTMH and processed for transmission electron microscopy, light epifluorescence, and laser scanning confocal microscopy. Glia were identified using anti-glial fibrillary acid protein (GFAP), antivimentin, and anti-cellular retinaldehyde binding protein antibodies. Anti-phosphodiesterase gamma and antirhodopsin were used for cone and rod photoreceptors, and anticytokeratin was used for retinal pigment epithelium. The findings were correlated with the clinical data before and after surgery. For statistical analysis, data were combined with those of a previous study by the authors of 18 opercula. RESULTS Opercula from 12 consecutive eyes of 12 patients were studied. In all opercula, GFAP, vimentin, and cellular retinaldehyde binding protein-positive glia were present. Six (50%) of 12 opercula contained more than 5 photoreceptors with somata and internal photoreceptor fibres, but lacking outer segments, demonstrating strong immunoreactivity to anti-phosphodiesterase gamma without antirhodopsin reactivity consistent with cones. Further, 2 (17%) of 12 opercula showed few cones (1-5 cones), and 4 (33%) of 12 contained only glia. Clinicopathologic correlation of the 30 opercula from the 2 studies showed that eyes with opercula containing more than 5 photoreceptors were associated with a worse anatomical closure rate after initial surgery, compared with those with fewer than 5 photoreceptors (P =.004). Once closure had been achieved with reoperation, median postoperative vision was similar in both groups (20/40 and 20/60, respectively). CONCLUSIONS A spectrum of opercula occur in FTMH ranging from those containing only glia to those containing numerous cones. The extent of foveal neuroretinal tissue loss may affect the outcome of surgery.