ILM Peeling Versus Inverted Flap Technique for Treatment of Macular Hole: Near Visual Acuity Outcomes

Idiopathic full-thickness macular hole (MH) is an anatomic defect of the macula caused by the traction of the vitreous. Interruption of all neural retinal layers from the internal limiting membrane (ILM) to the retinal pigment epithelium (RPE) is present. Although other therapeutic approaches like pneumatic or enzymatic vitreolysis may lead to MH closure, pars plana vitrectomy (PPV) remains a gold standard for the treatment of full-thickness MH. Combination of PPV with full ILM peeling showed excellent results in small to medium MH, however the success rates dropped significantly with the increasing size of MH. PPV with inverted flap technique was introduced to address this issue and showed great results in MH of all diameters. In inverted flap technique, ILM is peeled around the MH and small piece of it is placed over the MH. It is speculated, that it serves as a scaffolding for gliosis allowing it to close large MHs. Besides gliosis, the ILM flap seals the MH by secluding communication between the vitreous and subretinal space, creating a closed compartment enabling the RPE to pump out fluid effectively. However, it is not known whether the ILM left in the macular hole might not hinder the healing process and full closure of macular hole. The aim of this study is to perform a detailed assessment of the state of the macula and near best corrected visual acuity and to compare the results of complete ILM peeling and ILM flap technique.

This is a prospective randomised study comparing the near visual acuity outcomes using Salzburg Reading Desk in pseudophakic patients with idiopathic full-thickness MH treated with PPV with ILM peeling versus inverted flap technique. Participants are randomized in a 1:1 ration to undergo 25-gauge PPV with complete ILM peeling or with circular inverted flap technique with sulphur hexafluoride as a tamponade and recommendation to maintain reading position for 3 days.

At baseline visit (D1) one day prior to the operation, patients undergo distance best corrected visual acuity (BCVA) exam using ETDRS charts, intraocular pressure (IOP) measuring using the non-contact tonometry, anterior segment slit-lamp examination, fundus biomicroscopy, microperimetry and optical coherence tomography (OCT).

At month 3 (M3) and month 6 (M6) visits, patients undergo distance BCVA exam using ETDRS charts, near BCVA exam using the Salzburg reading desk (SRD Vision, NY, USA), IOP measuring using the non-contact tonometry, anterior segment slit-lamp examination, fundus biomicroscopy, microperimetry, and OCT. The closure of macular hole and post-operational complications are assessed.

Distance BCVA is performed using ETDRS charts and recorded in logMAR.

Microperimetry is performed using the MAIA Confocal Microperimeter (CenterVue S.p.A, Padova, Italy). Expert exam 4-2 of the study eye is performed two times and the average of macular integrity score, average threshold score and fixation stability P1 and P2 are recorded.

OCT is performed using the Spectralis OCT (Heidelberg Engineering GmbH, Heidelberg, Germany). Macula of the study eye is scanned in 512 horizontal scans in the angle of 20x20 degrees with the spacing of 11 um in High Speed mode with noise reduction set to ART=5. The minimum and basal macular hole diameter is recorded, and the staging of the macular hole is performed using both the Gass and International Vitreomacular Traction Study Classification System. Presence or absence of epiretinal membrane is recorded.

Near BCVA is performed using the Salzburg reading desk. The best near correction is determined first using the Jaeger Reading Eye Charts. Examination on Salzburg reading desk is performed afterwards in Czech with the reading distance set to 40 cm with contrast and luminance set to 100%. Progressively smaller text is presented to the patient until his reading speed falls under 80 words per minute (wpm) or until his word miss rate is higher than 1. At this point, patient is presented with 5 different sentences with the same text size. Test is ended if the patient cannot exceed the reading speed of 80 wpm or if his word miss rate is higher than 1 3 or more times for the same text size. The smallest text size where reading speed is over 80 wpm or word miss rate is 1 or lower is recorded in logMAR as near BCVA.