Epiretinal membrane (ERM) formation on OCT causes which characteristic distortion of the foveal contour, and what is the threshold for surgical intervention?
- A Loss of foveal depression (ectopic inner foveal layers), macular thickening, and metamorphopsia; surgery indicated for VA ≤6/12 or disabling metamorphopsia ✓
- B Subretinal fluid at the fovea; surgery indicated for any ERM
- C Choroidal thinning and RPE disruption; surgery indicated for central scotoma
- D Hyperreflective subretinal deposits; surgery prevents progression to BRVO
Correct answer: A. Loss of foveal depression (ectopic inner foveal layers), macular thickening, and metamorphopsia; surgery indicated for VA ≤6/12 or disabling metamorphopsia
Explanation
ERM on OCT causes loss of the normal foveal depression, ectopic inner foveal layers (IFL sign), irregular retinal surface with tractional folds, and increased central macular thickness. Clinically, patients have metamorphopsia and reduced VA. The indication for pars plana vitrectomy with membrane peeling is VA of 6/12 or worse and/or disabling metamorphopsia (Amsler grid distortion) significantly affecting quality of life. Asymptomatic ERMs with good VA are monitored. Internal limiting membrane peeling at the time of ERM surgery reduces recurrence rates.
Reference: Khurana Comprehensive Ophthalmology, 7th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.