Sir,

We read with interest the article on ‘Reduction of thickness of ganglion cell complex after internal limiting membrane peeling during vitrectomy for idiopathic macular hole’ by Baba et al.1

In the discussion regarding the possible mechanisms of ganglion cell complex (GCC) thickness reduction, it is noteworthy to include that indocyanine green (ICG) can cause the alteration in the surgical planes during internal limiting membrane (ILM) peeling in macular hole (MH) surgery. In a study by Gandorfer et al,2 all membrane specimens from ILM peel revealed not only the ILM, 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 outer undulating aspect of the ILM but within the outermost retinal layers, which would account for the thinning of the GCC layer.

The conclusion by the authors in this study is controversial. ILM peel may improve the success of anatomical closure of a MH. Macular hole surgery, with or without the use of adjuncts, had high success rates prior to the recently accepted practice of ILM peeling. It is our understanding that many centres do not perform an ILM peel routinely for certain stages of MH and despite this, achieve high rates of anatomical closure. Smiddy et al3 reported a high anatomic MH closure rate of 93% with a complete, partial or no ILM peel. Brooks Jr4 reported 82% primary anatomical closure of MH without ILM peel. ILM peel is not essential for MH <300 μm and <6 months in duration, and its value in other stages of macular hole is still not proven, though widely accepted. We suggest that, ILM peel may aid in MH closure but is not essential as the authors concluded in their study.