Comparisons of Cone Electroretinograms After Indocyanine Green-, Brilliant Blue G-, or Triamcinolone Acetonide-assisted Macular Hole Surgery

Purpose: To compare the function of retinal ganglion cells (RGCs) using the photopic negative response (PhNR) in patients who had undergone indocyaine green (ICG)-assisted, brilliant blue G (BBG)-assisted, or triamcinolone acetonide (TA)-assisted internal limiting membrane (ILM) peeling during macular hole (MH) surgery.

Methods: Forty-eight eyes of 48 patients with a macular hole were randomly divided into those undergoing ICG-assisted, BBG-assisted, or TA-assisted vitrectomy (n = 16 for each group). Full-field cone ERGs were recorded before and 1, 3, 6, 9, and 12 months postoperatively. The amplitudes and implicit times of the a-waves and b-waves and the amplitudes of the oscillatory potentials (OPs) and PhNRs were measured. The mean deviations (MDs) of standard automated perimetry and the best-corrected visual acuity (BCVA) were measured. The circumferential retinal nerve fiber layer (RNFL) thickness was evaluated by SD-OCT.

Results: All macular holes were closed with a significant improvement of the BCVA and MD without differences among the groups. There was no significant difference between the preoperative and postoperative RNFL thickness. The implicit times of the a-waves and b-waves were significantly prolonged, and the ΣOPs amplitude was significantly decreased postoperatively in all groups. These ERG changes were not significantly different among the groups. The postoperative PhNR amplitudes were significantly lower in the ICG group than in the BBG or TA group.

Conclusions: The results indicate that the PhNR may detect subclinical impairments of RGCs caused by the possible toxic effect of ICG. This finding adds to the data that BBG and TA may be safer than ICG for use during MH surgery.