Epiretinal membrane characteristics correlate with photoreceptor layer defects in lamellar macular holes and macular pseudoholes.

Purpose: To report on epiretinal membrane (ERM) characteristics and photoreceptor layer integrity of lamellar macular holes (LMHs) and macular pseudoholes (MPHs), and to compare with clinical course in operated and untreated eyes.

Methods: We consecutively reviewed the charts of patients with LMH and MPH between 2003 and 2013. For clinical analysis, we included 87 eyes (48 with LMH, 39 with MPH) with a minimum follow-up of 6 months. Of these, we included 64 eyes (37 with LMH, 27 with MPH) for high-resolution spectral domain optical coherence tomography analysis with examinations fulfilling the required resolution and quality of optical coherence tomography images. Epiretinal membranes were termed "typical tractional ERM" if presenting with contractive properties, or "atypical epiretinal tissue" if presenting as epiretinal material of homogeneous medium reflectivity without contractive properties. Integrity or discontinuity of the inner and outer segment (IS/OS) and the external limiting membrane (ELM) was evaluated by differentiating between "defect present" and "defect absent."

Results: In eyes with LMH, atypical epiretinal tissue presented in 29%, typical tractional ERMs were seen in 57%, and a combination of both in 14%. In contrast, eyes with MPH rarely presented atypical epiretinal tissue, and typical tractional ERMs were found in 89%. Comparing cases with LMH, eyes with atypical epiretinal tissue showed significantly more defects of the IS/OS and the ELM than eyes with typical tractional ERM. Both IS/OS and ELM defects correlated with a significant lower best-corrected visual acuity. Defects of the IS/OS were seen in 41% of LMH and 11% of MPH. Defects of the ELM revealed in 27% of LMH and in 11% of MPH. Operated eyes with disrupted IS/OS but intact ELM had significant better best-corrected visual acuity than eyes with defects in both layers.

Conclusion: Atypical epiretinal tissue is related to the presence of photoreceptor layer defects and to poor visual acuity. It seems that integrity of the ELM is most important for functional recovery after surgery in both LMH and MPH. The presence of atypical epiretinal tissue in eyes with LMH may represent differences in the pathogenesis compared with MPH, and might have therapeutic implications for the proceeding with macular surgery in selected cases.