Age, Retinal Layer Findings Affect Visual Recovery After Epiretinal Membrane Repair

Age and the presence of disorganization of the retinal inner layers (DRIL) can affect the rate of visual function recovery in patients who have undergone early surgical intervention for the treatment of idiopathic epiretinal membranes (ERMs), according to a study published in the Canadian Journal of Ophthalmology. The study shows that 24 months post pars plana vitrectomy (PPV), preoperative DRIL and strong adhesion between the ERM and the retina negatively influence visual acuity. All PPV procedures were conducted with trypan blue staining and internal limiting membrane peeling.

In this retrospective study, researchers reviewed records of 121 eyes of 117 patients (mean age 67±12.2 years, 74 women, 43 men) before and after vitrectomy for 24 months. During each follow up, physicians conducted an ophthalmic exam and spectral-domain optical coherence tomography (SD-OCT) imaging. The researchers analyzed the type of ERM, epiretinal proliferation (EP), central retinal thickness (CRT), linear interdigitation zone (IZ) defect, type of inner retinal structure distortion, and the type of connection between the retina and the ERM.  

The researchers identified 3 eyes with stage 1, 63 with stage 2, 35 with stage 3, and 20 with stage 4 ERM. Eyes with advanced ERM of grades 3 and 4 had lower preoperative visual acuity and higher CRT, the report shows. The mean CRT and visual acuity before surgery was 509.4 µm and 0.79 logarithm of the minimum angle of resolution (logMAR), respectively. 

At the 24 month postoperative exam, the records show patients had a decrease in CRT (346±96.8 µm), improvement in visual acuity (0.21 logMAR), and recovery of retina structure, as well as aa decreases in DRIL (16.53% vs 4.13%; P <.001), ectopic inner foveal layer (EIFL) (28.93 vs 10.92%; P <.001) and stretched outer nuclear layer (52 vs 19.83%; P <.001). Age, DRIL, and EIFL (P =.007) are factors that influence CRT at the end of the study. CRT recovered faster in younger patients and those without DRIL (P <.001) and EIFL (P <.001).

“Tractional forces exerted by an ERM might influence retinal layers and, as a result, also visual acuity in several ways,” researchers explain. “We noted an elevation (stretching) of the [outer nuclear layer (ONL)], EIFL, and DRIL.”

Early postoperative analyses showed multiple factors: age (P =.021), IZ defect (P =.048), presence of cotton ball (P <.001), DRIL (P <.001), EIFL (P =.02), and stretched ONL (P =.02) or strong adhesion of the ERM to the retina (P <.001) negatively influenced the recovery of visual acuity. However, at the 24 month follow up, DRIL and strong adhesion between the ERM to the retina still influenced visual function.