Preferential hyperacuity perimeter and prognostic factors for metamorphopsia after idiopathic epiretinal membrane surgery.

PURPOSE

To document changes in metamorphopsia via preferential hyperacuity perimeter and to identify prognostic factors related to favorable metamorphopsia outcome after idiopathic epiretinal membrane surgery.

DESIGN

Prospective, consecutive, interventional case series.

METHODS

We prospectively included 29 eyes of 27 patients who underwent successful vitrectomy for idiopathic epiretinal membrane. All eyes underwent examinations before surgery and at 2 weeks and 1, 3, and 6 months after surgery. Metamorphopsia was assessed by using a preferential hyperacuity perimeter. Several clinical factors were analyzed to reveal relationships with final metamorphopsia outcome, including the duration of symptoms, best-corrected visual acuity, and spectral-domain optical coherence tomography findings. Spectral-domain optical coherence tomography findings included assessment of central foveal thickness, and the integrity of the photoreceptor inner segment and outer segment (IS/OS) junction.

RESULTS

At baseline, preferential hyperacuity perimeter detected areas of distortion in 15 eyes (51.7%). At 6 months after surgery, there was significant reduction in metamorphopsia (P = .001), which was paralleled with significant improvement of best-corrected visual acuity and reduction of central foveal thickness (P < .001). At 6 months after surgery, the degree of metamorphopsia was related significantly to the severity of preoperative metamorphopsia and central foveal thickness at baseline (ρ = 0.856; P < .001; ρ = 0.412; P = .027; respectively). Eyes with broadly disrupted IS/OS junction of more than 200 μm before surgery revealed significantly poorer postoperative metamorphopsia than those with intact or narrowly disrupted IS/OS junction (P = .001). However, duration of symptoms and baseline best-corrected visual acuity were not correlated with final metamorphopsia (P = .625 and P = .052, respectively).

CONCLUSIONS

Significant reduction of metamorphopsia paralleled the improvement of best-corrected visual acuity and central foveal thickness until 6 months after idiopathic epiretinal membrane surgery. The significant predictors for postoperative metamorphopsia outcome were the degree of preoperative metamorphopsia, central foveal thickness, and the photoreceptor IS/OS junction integrity at baseline.