LAUSR

Dear Editor, I diopathic full-thickness macular holes (FTMH) are among the more frequent macular diseases. Pars plana vitrectomy (ppv) with peeling of the ILM is considered the gold standard for FTMH without vitreomacular traction. Although the small-incision, sutureless ppv is a safe procedure, undesirable complications such as retinal detachments (RD) can influence the visual outcome. A retrospective, non-comparative, consecutive case series on 479 eyes with FTMH that underwent 23 gauge ppv (23G-ppv) and peeling of the ILM between February 2011 and January 2016 in two major surgical retinal centres in Germany (Department of Ophthalmology, St. Franziskus Hospital M€ unster and Eye Clinic Sulzbach, Knappschaft Hospital Saar) to assess the incidence of postoperative RD was performed. Furthermore, best corrected visual acuity (BCVA) in logMAR was compared for a line gain or loss 6 months after surgery. Ten out of 479 patients experienced postoperative RD (2.1%). The median time between surgery and RD was 106.7 days (13–489 days) with two peak time points of occurring RD: after 31 days (60% of patients) and 130 days (30% of patients). Only 1 patient presented the RD after more than a year (489 days) (Table 1). More than 6 months after surgery, BCVA decreased by 1.5 lines (logMAR 1.0 0.64) in the subgroup of patients with RD compared to gain of 3.8 lines (logMAR 0.42 0.28) in the non-RD group. There are several reports about RD following ppv. Rizzo et al. (2010a) found a frequency of 1.4% in 2598 small-incision, sutureless vitrectomies for predominantly macular diseases and an incidence of RD of 1.7% (31 of 1862) after 25or 23-gauge vitrectomies for epiretinal membranes and macular holes again in a follow-up of 6 month, but a slightly lower rate of RD after conventional 20-gauge ppv (1.2%) (Rizzo et al. 2010b). In a study of more than 600 eyes, Guillaubey et al. could demonstrate a significantly higher rate of RD after 20-gauge macular hole surgery compared to 20gauge vitrectomies for epiretinal membranes (6.6% versus 2.5%) (Guillaubey et al. 2007). A stronger depression necessary to induce posterior vitreous detachment and traction involving the vitreous base during the complete peripheral ppv could be a risk factor. In addition, eyes with vitreomacular traction seem to have a significantly higher incidence of breaks (Tarantola et al. 2013). Mechanical detachment of the posterior vitreous might be an important risk factor in our study as well as the retinal breaks were located with preference of the inferior hemisphere but not in direct proximity of the sclerotomies and may be responsible for the first peak of RD after 1 month. Ramkissoon et al. (2010) recognized that iatrogenic induction of posterior vitreous detachment significantly (~3-fold) increased the risk of RD (Ramkissoon et al. 2010). Another reason for the emerge of new retinal breaks could be the shrinking and subsequent tearing of the incomplete removed peripheral vitreous which might lead to the second peak of RDs after approximately 130 days. In our cohort, patients with RD had a loss of 1.5 lines (logMAR 1.0 0.64) after 6 months, which can be explained on the one hand by the macula-off situation in 6/10 patients, but also by the postoperative persisting macular hole. However, vitreoretinal surgery of FTMH is a safe procedure and successful in terms of visual acuity. All possible complications should be regularly checked in clinical postoperative follow-up examinations and explained to the patient before surgery. Especially during the period with the highest risk of RD, approximately 1 and 4 months after macular surgery, dilated fundus examinations should be performed.