Improvement of horizontal macular contraction after surgical removal of epiretinal membranes

Abstract

Purpose: To determine whether horizontal macular contraction caused by epiretinal membranes (ERMs) improves after surgical removal.

Methods: In this prospective, single-center, observational study, 63 consecutive patients with unilateral idiopathic ERM in one eye and no retinal disease in the fellow eye underwent pars plana vitrectomy. Fundus photography and optical coherence tomography (OCT) were performed preoperatively and at 3 months postoperatively. The area enclosed by superior and inferior major vessels from the optic disc to the fovea (area under major vessel (AUV)) and the macroscopic diverging angle (MDA) between superior and inferior major vessels were calculated using digital image analysis of fundus photographs and compared pre- and postoperatively.

Results: AUV was significantly smaller in the eyes with ERM compared with the normal fellow eyes (P<0.001). Significant postoperative change in AUV and MDA was demonstrated after ERM removal (P<0.001). However, postoperative AUV of grade 2 and 3 ERM eyes was still significantly smaller than that of normal fellow eyes. Macular thickness differences measured with stratus OCT were positively correlated with AUV differences.

Conclusions: Retinal topographic changes caused by ERM improved in part after ERM removal. The improvement of topographic changes were correlated with tomographic changes detected with OCT.

Figure 1

An example of a preoperative and postoperative image pair from a patient with an epiretinal membrane. A patient's fundus photographs are shown (top left) preoperatively with an epiretinal membrane and (top right) postoperatively. The binary images of major vessels from (bottom left) preoperative and (bottom right) postoperative fundus photographs are shown.

Figure 2

A schematic showing the two features of macular contraction. (Left) Area under major vessels (AUV) in preoperative and postoperative images were calculated from the area enclosed by superior and inferior major vessels from the optic disc to the fovea. (Right) Macroscopic diverging angle (MDA) between superior and inferior major vessels were calculated using digital image analysis of fundus photographs.

Figure 3

(Left) Linear regression analysis demonstrates negative correlation between area under major vessel differences (ΔAUV) and central macular thickness differences (ΔCMT). (Middle) BCVA differences (ΔBCVA) did not show significant correlation with ΔAUV. (Right) ΔBCVA showed positive correlation with ΔCMT.