We read with interest the article “Progressive Thinning of Regional Macular Thickness After Epiretinal Membrane Surgery” by Kumagai et al.
1 The study provides invaluable long term follow-up of patients operated for epiretinal membrane (ERM) with internal limiting membrane peeling (ILM).
After analysis of 53 patients, it was found that the temporal retina became thinner than baseline value and on comparison with the normal eye, while the nasal retina remained thick. These findings also have been reported previously,
2 as also cited by the authors.
3 In this study, the authors mention that these findings are due to inner retinal defects deeper than the ganglion cell layer. We wish to highlight that this temporal nasal asymmetry also is believed to be because of close packing of ganglion cells and other retinal cells together in the papillomacular bundle, and also that the nasal side of the fovea may be more resistant to traction during surgery.
2 Furthermore, it has been speculated that after ILM peeling, foveal displacement toward the optic disc leads to stretching and thinning of the retinal parenchyma in the temporal subfield and postoperative retinal thickness in the nasal subfield.
2
While beginning the ILM peel, we prefer raising the ILM flap from the temporal aspect to avoid damage to the papillomacular bundle. As all these patients were operated by a single surgeon, such a fixed surgical protocol also may be responsible for temporal thinning due to inadvertent traction and instrument retina interaction.
4
We hope our discussion adds to the study and await the authors' response.