epiretinal

Epiretinal refers to structures or processes on the inner surface of the retina. In ophthalmology, an epiretinal membrane (ERM), also known as macular pucker, is a thin fibrocellular layer that forms on the inner limiting membrane of the retina, typically over the macula. Most ERMs are idiopathic and occur in aging eyes, but they can also be secondary to retinal detachment surgery, inflammatory disease, diabetic retinopathy, or ocular trauma.

By contracting, the membrane exerts tangential traction on the underlying retina, producing wrinkling or distortion of the macula. This can lead to metamorphopsia (distorted vision) and a progressive decline in central visual acuity, though some cases remain mild or stable.

Diagnosis is based on dilated fundus examination and imaging, particularly optical coherence tomography (OCT), which shows macular thickening and a membrane on the inner limiting membrane. Fluorescein angiography is rarely required.

Treatment is typically conservative when vision is only mildly affected. If symptoms are significant or progressive, pars plana vitrectomy with membrane peeling is performed, often with peeling of the internal limiting membrane to reduce recurrence. Most patients experience some visual improvement, though metamorphopsia may persist, and recovery can be partial and slow. Surgical risks include cataract progression, infection, bleeding, retinal tears or detachment, and membrane recurrence.

Epidemiology and prognosis: ERMs are common in older adults and may be idiopathic or secondary to eye surgery or inflammation. The prognosis depends on the extent and duration of macular distortion; timely treatment improves the likelihood of meaningful visual gains.