• Insights Into Epiretinal Membranes and Staging

    By Lynda Seminara and selected by Richard K. Parrish II, MD

    Journal Highlights

    American Journal of Ophthalmology, March 2017

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    Govetto et al. reviewed the records of 172 patients (194 eyes) diagnosed with epiretinal membranes (ERMs). Based on findings from spectral-domain opti­cal coherence tomography (SD-OCT), they identified a novel clinical entity associated with substantial vision loss: ectopic inner foveal layers.

    The authors also proposed a 4-stage classification system for ERMs. Stage 1 ERMs are thin, with a foveal depres­sion, and have readily distinguishable retinal layers. Stage 2 membranes lack a foveal depression and exhibit retinal distortion, with stretching or widening of the outer nuclear layer, although retinal layers still are distinct. Stage 3 denotes emergence of continuous ectopic inner foveal layers and mainte­nance of observable retinal layers. Stage 4 ERMs are thick, with a disrupted macula, distorted and indistinguishable retinal layers, and continuous ectopic inner foveal layers.

    The ERMs in this study were graded as follows: stage 1, 43 eyes (22.1%); stage 2, 88 eyes (45.4%); stage 3, 51 eyes (26.3%); and stage 4, 12 eyes (6.2%). Continuous ectopic inner foveal layers were detected in 63 eyes (32.5%).

    Successive ERM stages were associ­ated with progressively reduced best-corrected visual acuity (BCVA), thick­ening of the central fovea, and greater prevalence of tractional cystoid macu­lar edema and ellipsoid disruption. The presence of ectopic inner foveal layers correlated with poorer BCVA, even when controlled for other potential causes of reduced BCVA.

    Sixty-three eyes were scheduled for surgery. During follow-up (mean, 22 months) of the nonsurgical eyes, 9 of 32 ERMs progressed from stage 1 to 2, 10 of 77 from stage 2 to 3, and 2 of 17 from stage 3 to 4. In all cases, progres­sion was accompanied by a significant decline in BCVA. No progression was seen in 108 eyes.

    The authors concluded that the presence of continuous ectopic inner foveal layers, as revealed on SD-OCT, is a prognostic factor for significant visual loss; and they proposed an OCT-based grading system for ERMs. Their study confirmed that the inner retinal layers of the macula may be particu­larly sensitive to tractional stress and demonstrated that ERM formation may significantly alter the microanatomy of the inner fovea.

    The original article can be found here.