THE EFFECT OF INTERNAL LIMITING MEMBRANE PEELING ON IDIOPATHIC EPIRETINAL MEMBRANE SURGERY, WITH A REVIEW OF THE LITERATURE

Purpose: To examine the effect of internal limiting membrane (ILM) removal on epiretinal membrane (ERM) surgery by comparing best-corrected visual acuity (BCVA), optical coherence tomography central macular thickness (CMT) changes, ERM recurrence, and need for repeat surgery. Methods: Retrospective study of 251 consecutive patients (251 eyes) who underwent pars plana vitrectomy for idiopathic ERM by a single surgeon with over 1 year of follow-up data. Data were collected preoperatively and postoperatively at 3 months, 1 year, 2 years, and at the last visit. The ILM was not specifically removed in the earlier group of patients and was removed after staining of the ILM in the later group. Results: One hundred and forty eyes (55.8%) did not have an ILM peel (non-ILM group), and 111 eyes (44.2%) did have an ILM peel (ILM group). There were no significant differences between groups in age, gender, preoperative BCVA, preoperative intraocular pressure, preoperative CMT on optical coherence tomography, and cataract status. Total follow-up time for the ILM group was 32.1 months and 45.4 months for the non-ILM group (P = 0.002). Both groups had improvement in BCVA. The ILM group improved by 12 Early Treatment Diabetic Retinopathy Study letters and the non-ILM group improved by 10.5 Early Treatment Diabetic Retinopathy Study letters. There was no significant difference in the final BCVA (P = 0.18) or total change of BCVA (P = 0.48). Cataract status preoperatively did not affect the total change of BCVA, but being phakic at the most recent visit was associated with a slight loss of visual acuity. Both groups had improvement in optical coherence tomography appearance, for the CMT in the ILM group decreased by 83 mm and the CMT in the non-ILM group decreased by 110 mm. There was no significant difference in the final CMT (P = 0.07); however, the non-ILM group tended to have a lower final CMT. Some degree of ERM recurrence was detected by slit-lamp biomicroscopy in 2 eyes (1.8%) of the ILM group and in 32 eyes (22.9%) of the non-ILM group (P <= 0.0001). None of the eyes with ILM removal required repeat vitrectomy, whereas 17 eyes (12.1%) of the non-ILM group did require vitrectomy, showing that ILM removal had a significant effect on the need for repeat vitrectomy (P, 0.0001) between non-ILM versus ILM peel groups. Conclusion: The rate of recurrent ERM and need for repeat ERM surgery is lower in eyes where the ILM is removed with the ERM, whereas BCVA and CMT were similar with or without ILM removal. Complete ILM removal around the macula should be considered for the treatment of eyes with idiopathic ERMs to reduce the incidence of ERM recurrences.