J Retin.  2022 May;7(1):21-26. 10.21561/jor.2022.7.1.21.

Topographical Characteristics of the Macula after Removing the Internal Limiting Membrane

• Kim SH
• Lee JJ
• Park SW
• Byon IS
• Lee JE

• KMID: 2552163
• DOI: http://doi.org/10.21561/jor.2022.7.1.21

Abstract

Purpose
The topographic characteristics of the macula where the internal limiting membrane (ILM) had been removed were investigated to provide a biomarker to diagnose the post-ILM removal macula (PIRM).
Methods
This study included 54 patients who had undergone vitrectomy and ILM peeling for idiopathic epiretinal membrane or macular hole. Their medical records were retrospectively reviewed. Fundus photographs and optical coherence tomography (OCT) obtained at least 1 year postoperatively were analyzed. Macular thickness was compared to that of the fellow non-operated eye in nine early treatment diabetic retinopathy study (ETDRS) subfields. The incidence of dissociated optic nerve fiber layer (DONFL) and notable ILM removed area were assessed using photographs and en-face OCT images.
Results
The analyzed images were obtained at an average of 15.6 months postoperatively. Macular thickness showed significant differences among the four ETDRS subfields. Typically, the center and nasal subfields were thickened. The inner temporal to inner nasal thickness ratio was the most diagnostic with an area under the curve of 0.899. The ILM-removed area was notable in 21 eyes (38.9%) from the photographs and 19 eyes (35.18%) from the en-face image. DONFL was noted in 37 (68.5%) and 39 (72.2%) eyes, respectively.
Conclusions
PIRM showed the asymmetric thickening of the nasal subfields, and low parafoveal temporal to nasal thickness ratio was most diagnostic. Our results may be helpful in diagnosing PIRM with unknown previous ophthalmic history.

Keyword

Dissociated optic nerve fiber layer appearance; Epiretinal membrane; Internal limiting membrane peeling; Macular hole; Topographic characteristics