Indocyanine green-assisted peeling of the internal limiting membrane may cause retinal damage

PURPOSE: To demonstrate possible retinal damage caused by indocyanine green dye for staining of the internal limiting membrane in surgery for idiopathic macular hole. METHODS: Consecutive interventional case series. We report on the ultrastructural findings of the internal limiting membrane in 10 eyes of 10 patients. RESULTS: All specimens revealed not only the internal limiting membrane, but also some small amounts of retinal elements, such as the plasma membrane of Müller cells and other undetermined structures. This indicates a cleavage plane not exactly at the inner undulating aspect of the internal limiting membrane but within the innermost retinal layers. CONCLUSION: Dilutions of indocyanine green as recommended in the literature may alter the structure of the retina to some degree. Possible factors responsible for this inadvertent action may include (1) concentration, (2) osmolarity pH, (3) time of tissue contact, and (4) mechanical factors from more forceful traction during peeling. Although functional consequences of these findings remain unclear as yet, factors that may induce damage to the innermost retina should be elucidated.