Abstract
Purpose: :
There have been some concern of retinal toxicity associated with the use of indocyanine green (ICG) dye in macular hole surgery (MHS), which is commonly used in North America. Our goal was to compare multifocal electroretinography (mfERG) retinal functional results after successful surgeries performed with ICG versus trypan blue (TB), a dye mostly used in Europe.
Methods: :
In a prospective, randomized study, 26 eyes of 25 subjects with stage 2 to 4 idiopathic MH, underwent a pars plana vitrectomy with removal of the inner limiting membrane (ILM). In 14 eyes, ILM staining was performed with TB; in 12 eyes ICG was used. Both groups were identical in terms of age (65.4 vs 64.5 years, range: 42-74 y.o). The preoperative and follow-up examinations (at 3 weeks, 3, 6 and 12 months) included optical coherence tomography (OCT), mfERG (103 hexagons) and, assessment of best corrected visual acuity (BCVA). Due to postoperative cataracts development in many patients which were removed before the 5th months, only data at 6 and 12 months are presented.
Results: :
MH closure was achieved in 100% of the cases as determined with the OCT. BCVA improved significantly in both groups at 6 and 12 months (P<0.01). Improvement between groups was not different. The mean improvement at 6 and 12 months were 10 and 13 letters respectively for the TB group and 13 and 12 letters for the ICG group. The first two rings of the mfERG responses were averaged and P1 amplitude and latency were determined using the Veris software. Preoperatively, mfERG P1 amplitude was similar between groups (9.4 nV in TB Vs 8.4 nV in ICG). In the TB group, improvement was not significant at 6 months (2.4 nV) but significant at 12 months (3.5 nV, P<0.05) after MHS. In the ICG group, significant improvement occurred at both 6 months (5.1 nV, P<0.05) and 12 months (6.3 nV; P<0.01). At 12 months, P1 amplitude was 12.9 nV and 14.7 nV in the TB and ICG groups respectively (non significant group difference). P1 latency also improved significantly at 6 and 12 months in the ICG group, with 2 and 2.9 ms respectively going from 37.3 to 33.5 ms. In the TB group, P1 latency also improved but only at 12 months (1.7ms). However, both groups were not significantly different at 12 months (33.5 ms, ICG Vs 33.8 ms, TB).
Conclusions: :
Although the use of TB or ICG appear to yield to similar improvement in terms of BCVA and mfERG values at 12 months, faster improvement (at 6 months) was observed in the ICG group for mfERG data. Considering that ICG dye allows a better visualization of the ILM according to our surgeons, our small sample study seems to favour the maintenance of ICG use for MHS.
Clinical Trial: :
none
Keywords: electrophysiology: clinical • electroretinography: clinical • macular holes