Retinal function assessment of trypan blue versus indocyanine green assisted internal limiting membrane peeling during macular hole surgery

Objective: To compare multifocal electroretinography (mfERG) retinal function and the anatomical and visual outcomes of macular hole surgery performed with indocyanine green (ICG) or trypan blue (TB). Design: Prospective, randomized study. Participants: Twenty-five eyes of 24 patients. Methods: Patients underwent a pars plane vitrectomy with removal of the internal limiting membrane. In 14 eyes, internal limiting membrane visualization during macular hole repair was performed using TB, and ICG was used in 11 eyes. The examination protocol (performed before surgery and at 3 weeks, 3 months, 6 months, and 12 months after surgery) included optical coherence tomography, mfERG (mfERG-103 hexagons), and assessment of best corrected visual acuity (BCVA) and contrast sensitivity (CS). Results: Closure of macular hole was achieved in 100% of the cases. In the TB group, P1 amplitude and implicit time improved significantly at 12 months after surgery (P < 0.05), whereas in the ICG group, significant improvement occurred at both 6 (P < 0.05) and 12 months (P < 0.01). BCVA improved significantly in both groups at 6 and 12 months (P < 0.01). Both groups also showed a statistically significant CS improvement at spatial frequency of 6 cycles per degree (P = 0.01) 1 year postoperatively. At 12 months, improvement of P1 amplitude and implicit time, BCVA, and CS was not different between groups. Conclusions: In this study, the use of TB or ICG appears to yield similar improvement in terms of BCVA, CS, and mfERG amplitude and implicit time changes at 12 months.