The impact of extent of internal limiting membrane peeling on anatomical outcomes of macular hole surgery: results of a 54-week randomized clinical trial

Abstract

Purpose: To compare the anatomical outcomes of different extents of internal limiting membrane (ILM) peeling in idiopathic macular hole surgery.

Methods: Prospective, parallel-group, randomized clinical trial. A total of 121 eyes of 121 patients with idiopathic macular hole underwent pars plana vitrectomy, and peeling of the ILM with a diameter of two disk diameters (DD) or 4DD based on randomization. The main outcome was the proportion of eyes with complete hole closure at 12 months. The second outcome was the hole closure grading stratified by macular hole closure index (MHCI) at each visit.

Results: At 12 months, there was no significant difference in anatomical outcomes with complete closure achieved in 52 (82.5%) of 63 eyes in the 2DD group and 53 (91.4%) of 58 eyes in the 4DD group (p = 0.15). For subjects with MHCI ≤0.5 (n = 24), complete closure rate was significantly lower in the 2DD group compared to the 4DD group (p = 0.012; 18.2% versus 75.9%, respectively). Average BCVA was lower in 2DD group than 4DD group (p = 0.014). By contrast, when MHCI was >0.5, the complete closure rate between the two groups showed no significant difference: 96.2% (50 patients) versus 95.6% (43 patients), respectively (p = 0.185).

Conclusion: In patients with idiopathic full-thickness macular hole and MHCI ≤0.5, a larger ILM peel of 4DD tends to achieve better anatomical outcomes than a more limited 2DD peel.

Keywords: anatomical outcomes; different diameter of internal limiting membrane peel; functional outcomes; internal limiting membrane peeling; macular hole.

Figure 1

Measurement of macular hole closure index (MHCI). M and N represent the straight lengths of the detached photoreceptor arms. One end is located at the broken end point of the external limiting membrane (point E) and the other end is located at the junction of the detached photoreceptors and the retinal pigment epithelium (RPE) band (point D). The BASE is measured as the length of RPE band without attached photoreceptors.

Figure 2

Macular hole closure grading based on OCT image. (A) Grade A postoperative outcome. Note that the full‐thickness defect in the macular hole is closed, but the foveal retina has a bridge‐like shape with persistence of foveal subretinal fluid. (B) Grade B postoperative outcome. The macular hole is closed with a normal‐appearing foveal morphology. (C) Grade C1 postoperative outcome. Note that the full‐thickness defect in the macular hole is closed, but the fovea is markedly abnormal and thinner with extensive or complete loss of ellipsoid zone and external limiting membrane with a V‐shape contour. (D) Grade C2 postoperative outcome. The macular hole remains open, but the neurosensory retina at the edge of the hole demonstrates relatively complete approximation with the underlying retinal pigment epithelium (RPE). (E) Grade C3 postoperative outcome. The macular hole remains open and the edges of the neurosensory retina also remain detached from the RPE. Such a configuration was deemed to represent a surgical failure and repeat surgery was advised.

Figure 3

The Intraoperative clinical photograph demonstrating the protocol of internal limiting membrane peel.

Figure 4

Flowchart showing the progression of patients in the study.

Figure 5

Noninferiority test of 2DD–4DD diameters ILM peeling for complete closure rate at month 12. CI = confidence interval; DD = disk diameter; ILM = internal limiting membrane.

Figure 6

Receiver operating characteristic (ROC) curve for macular hole closure index (MHCI). When we analysed these grade A and grade B closure status combined together, we found the area under ROC curve was 0.928 (p < 0.05) compared with grade C closure, obtaining the MHCI cut‐off value as 0.505.

Figure 7

Improvement in best‐corrected visual acuity (BCVA) Letters From Baseline at Each Visit. (A) The improvement of all participants in BCVA letters during all visits. (B) The improvement of two intervention arms in BCVA letters at each visit separately.