Abstract: We identified and included four RCTs; these were conducted in Denmark, France, Hong Kong and the United Kingdom/Republic of Ireland and randomised 47, 80, 49 and 141 participants respectively. There was no evidence of a difference in the primary outcome (distance visual acuity at six months), nor in distance visual acuity at 12 months between randomised groups. However, there was evidence of improved best corrected distance visual acuity in the ILM peeling group at three months (WMD -0.09, 95% CI -0.17 to -0.02). We found no evidence for a difference in near vision between groups at any of the time points investigated. Overall, more participants in the ILM peeling group than in the no-peeling group had primary macular hole closure (OR 9.27, 95% CI 4.98 to 17.24); this held true when results were stratified by the stage of the macular hole. There was also evidence that those in the ILM peeling group were more likely to have final macular hole closure (OR 3.99, 95% CI 1.63 to 9.75). Fewer participants required further surgery in the ILM peeling group than in the no-peeling group (OR 0.11, 95% CI: 0.05 to 0.23). Rates of intraoperative and postoperative complications were similar in both groups. Based on the results of one study, there was no evidence that total VFQ-25 or EQ-5D scores differed between the groups at six months.  Based on this same study, ILM peeling is highly likely to be cost-effective. Although we found no evidence of a benefit of ILM peeling in terms of the primary outcome (visual acuity at six months), ILM peeling appears to be superior to its no-peeling counterpart as it offers more favourable cost effectiveness by increasing the likelihood of primary anatomical closure and subsequently decreasing the likelihood of further surgery, with no differences in unwanted side-effects compared with no peeling.

Plain-language summary: This review found four studies in which people who had undergone macular hole surgery with no ILM peeling were compared with those in whom the ILM was removed during the first surgery they had received. As well as reviewing published data from these four studies, we undertook an 'individual patient data (IPD) meta-analysis'. To undertake IPD meta-analysis one needs to collect all the raw data for each participant included in each of these RCTs before and after surgery and then combine all data together and analyse them. We were able to obtain data for each individual participant included in three of these four studies, which we then analysed and present in this review. Our results showed that at six and 12 months after the initial surgery to treat the macular hole the vision was no different between participants that received ILM peel and those who did not. At three months, however, the vision was better in those participants that received ILM peeling. More macular holes were closed and less re-operations had to be performed in participants who received ILM peeling with no differences in the number of complications between patients receiving ILM peeling or no peeling in the first surgery. There were no differences in the way participants perceived the benefits of the surgery. ILM peeling was found to be highly likely cost-effective, i.e. the cost of the treatment was justifiable by the benefits obtained from it. We conclude that ILM peeling compared with no peeling increases the chance for a macular hole to close with a single surgery and reduces the chances of people requiring additional surgery without unwanted side effects; as ILM peeling is very likely cost-effective, it may be considered the best available option for people with idiopathic FTMH.