Quantification of contrast recognizability in sequential epiretinal membrane removal and internal limiting membrane peeling in trypan blue-assisted macular surgery.

PURPOSE To evaluate the selectivity and strength of intraoperative trypan blue staining during removal of epiretinal membranes (ERMs) and the internal limiting membrane. METHODS Based on intraoperative videos, 51 consecutive chromovitrectomies in 51 patients with macular holes, macular pucker, vitreomacular traction syndromes, or persistent macular edema were retrospectively studied. Fifteen subjects underwent trypan blue, 14 indocyanine green, and 22 brilliant blue G chromovitrectomy. The main outcome measure was the color contrast between stained internal limiting membrane or ERM and the underlying unstained tissue by means of objective, quantitative, semiautomated chromaticity difference measurements. RESULTS Trypan blue stains both ERM and the internal limiting membrane (average chromaticity scores 8.51 and 7.09, respectively; P = 0.48). Internal limiting membrane chromaticity scores were similar for trypan blue (7.09) and brilliant blue G (6.81; P = 0.71) but clearly higher for indocyanine green (15.81; P = 2.45 × 10). CONCLUSION Under the premises of our study, trypan blue stains both ERM and the internal limiting membrane. Trypan blue's staining capacity of the internal limiting membrane is similar to that of brilliant blue G but significantly inferior compared with indocyanine green. Trypan blue, thus, represents a useful vital dye for chromovitrectomy, particularly in the presence of ERM, where it allows a sequential approach.