Purpose:
To assess whether the presence of the foveal depression on OCT is necessary for an improved final visual outcome in patients who have undergone removal of macular epiretinal membranes (ERM).
Methods:
Retrospective case series of 36 eyes in 36 patients who have undergone ERM peeling using standard three-port pars plana vitrectomy. Preoperative and postoperative assessment included logMar visual acuity, OCT thickness (1mm central macular thickness and foveal thickness) and presence or absence of foveal depression. Patients with at least one-month follow up were included.
Results:
The mean age was 70 ± 8 years with a follow up duration of 9.4 ± 7.4 months. The mean preoperative logMar visual acuity was 0.52 ± 0.19 (20/66 Snellen equivalent). The mean final logMar postoperative visual acuity was significantly improved to 0.35 ± 0.25 (20/45 Snellen equivalent, p<0.002). Overall, pre-operative 1 mm OCT central macular thickness was 416 (±98) µM as compared to post-operative thickness of 301 (± 67) µM (p<0.0005). Foveal thickness was significantly reduced (p<0.0005) from 416 (± 108) µM to 284 (± 83) µM post-operatively. 4/36 eyes had foveal depression on pre-operative OCT. Post-operatively, 23/36 patients had foveal depression. Of the 17/36 patients that had final visual acuity improvement of ≥2 Snellen lines, 12 (71%) had a final foveal depression. Of the 20 patients with a ≥ 30% decrease in foveal OCT thickness post-operatively, foveal depression was observed in the final OCT in 17 (85%) eyes. Pre-operative and post-operative characteristics by absence or presence of final foveal depression are shown in the table below. Both groups had similar initial visual acuity and OCT thickness (p>0.6).
Conclusions:
Presence of foveal depression observed on OCT following ERM removal is more likely to occur in eyes with improved final vision and OCT thickness. Although OCT thickness may have improved in eyes that did not achieve normal foveal architecture, the visual acuity may not have improved.
Keywords: imaging/image analysis: clinical • retina • macula/fovea