To determine the effect on the visual outcome after macular hole surgerywhen staining the internal limiting membrane (ILM) with indocyanine green(ICG) dye and to study the mechanism of the adverse effects.
Patients and Methods
We studied 40 eyes of 38 patients with an idiopathic macular hole (size,<0.5 disc diameter; duration, <12 months). The concentration, exposuretime, and amount of the ICG solution that was minimally required to make theILM visible were determined. The patients were randomly divided into group1 (20 eyes of 19 patients) who underwent ILM peeling without ICG staining,and group 2 (20 eyes of 19 patients) who underwent ILM peeling with ICG staining.Routine examinations were conducted during the 12-month follow-up period.Multifocal electroretinogram, optical coherence tomography, and fluoresceinangiography were performed on 31 eyes of 30 patients.
The macular hole was closed in all patients. Visual acuity was improvedin both groups, but it was significantly better in group 1 (median, 0.85)than in group 2 (median, 0.60; P = .02) after 12months. The improvement of visual acuity in group 1 (logarithm of the minimumangle of resolution [logMAR] units [SD], 0.82 [0.19]) was significantly betterthan that in group 2 (logMAR units, 0.67 [0.21]; P =.30). The multifocal electroretinogram and optical coherence tomographic findingswere not significantly different in the 2 groups. Fluorescein angiogram showedonly weak hyperfluorescence at the macula in some patients of both groups.
The results suggest that ICG staining should not be used as long asthe visibility of the retinal surface is good. However, ICG staining may beacceptable at a low concentration when a clear view of the retinal surfaceis unattainable. The results of the multifocal electroretinogram, opticalcoherence tomography, and fluorescein angiography suggest that the differencesin visual recovery were caused not only by pigment epithelial cell damageor retinal toxic effect but also probably by the effect of ICG staining onganglion cells and their axons.