The most challenging aspect of epiretinal membrane (ERM) peeling may be timing — early removal presents a chance for the membrane to reappear, although later surgery may impair restored visual acuity. An analysis published in BMC Ophthalmology assesses clinical outcomes for patients with diffractive multifocal intraocular lenses (MIOLs), and presents data comparing how evolving levels of ERM impact recovery.
The chart review evaluates visual results for 49 eyes of 49 participants: 11 with stage 2 ERM and 14 eyes with stage 3 ERM receiving pars plana vitrectomy (PPV) and ERM procedures, and 24 age-matched individuals used as a control group, also with diffractive MIOL. Care was provided at 2 centers in the Republic of Korea, and patients were followed for at least 12 months between February 2018 and November 2020. Procedures employed no intraocular tamponade or periocular medications — a postoperative course of topical moxifloxacin and prednisone acetate was prescribed.
At baseline, the only significant difference between case and control groups was central subfield thickness (CST) at 398.85±53.44 μm compared with 266.25±23.38 μm, respectively. ERM surgeries resulted in no retinal detachments, infections, or hypotony. Participants at either ERM stage showed significant improvements in CST at 1-, 2-, 6-, and 12-month visits (all P <.05). Also better at 1, 6, and 12 months was uncorrected and corrected distance visual acuity (UDVA and CDVA), and uncorrected near visual acuity (UNVA) outcomes (all P <.05).
Significant differences occurred, though, when comparing patients presenting stage 3 membrane with the superior uncorrected vision of control individuals: for UDVA, this difference was (P =.035), and UNVA (P =.029). However, no statistically large differences emerged between the stage 2 and control groups for UDVA or UNVA. Groups did not differ by CDVA (P =.121). Also, contrast sensitivity was considerably lower in ERM cohorts than control group in scotopic lighting at 4.0° (P =.041), and photopic conditions of 2.5° (P =.014) and 1.6° (P =.036).
Eyes with stage 3 membrane may have obtained reduced visual acuity due to changes in inner retinal structures, the investigators speculate, adding that light diffracted at the MIOL is diffracted again at the disrupted inner nuclear and plexiform layers — so even though a membrane is effectively peeled, the changed structures remain.
ERMs do not always progress quickly, thus evaluating membrane development is challenging. In previous studies, an abnormal vitreoretinal interface such as hyper-reflective foci or partial posterior vitreous detachment may create more risk for an ERM to develop after cataract procedures, according to the researchers. “In at-risk eyes, selecting an IOL with lower dysphotopsia and higher CS propensities than a diffractive-type MIOL may ultimately help avoid unnecessary vitrectomy for early ERM removal,” according to the report. Also, when patients choose a diffractive MIOL, “meticulous preoperative retinal evaluation for ERM” is essential.
The specialist who measured EIFL thickness was blinded to patient identity. Limiting this investigation is a relatively small cohort, although the study exceeds a minimum of 9 eyes per group to show significance (α) at 0.05, 0.90 power, and effect size 1.256. Prior to this analysis, there was scant data regarding visual outcomes for individuals with diffractive MIOL who underwent ERM peeling.
Kim H, Jeon S. Visual outcomes of epiretinal membrane removal after diffractive-type multifocal intraocular lens implantation. BMC Ophthalmol. Published online November 7, 2022. doi:10.1186/s12886-022-02649-8