Choroidal thickness change following vitrectomy in idiopathic epiretinal membrane and macular hole

To investigate changes in choroidal thickness following vitrectomy in eyes with epiretinal membrane (ERM) and macular hole (MH) METHODS: Choroidal thicknesses at the fovea and at 1 and 3 mm superior, inferior, temporal, and nasal to the fovea were measured using enhanced-depth imaging optical coherence tomography (EDI-OCT) before and 1 week, 1, 3, 6, and 12 months after vitrectomy. In 95 eyes with ERM and 56 with MH, the thicknesses were compared between baseline and each postoperative visit. The postoperative thickness changes from baseline were compared between the ERM and MH groups. Clinical factors associated with choroidal thickness change were also evaluated.

All choroidal thicknesses were significantly increased 1 week after vitrectomy compared to baseline in the ERM group (i.e. mean subfoveal choroidal thickness increased from 218 to 233 μm, P < 0.001). In the MH group, the increase was statistically significant only for inferior choroidal thicknesses. Such significant increase in choroidal thicknesses was not observed from 1 month postoperative in both groups. Postoperative SFCT change was significantly associated with combined cataract extraction (P = 0.026) and surgical indication (P = 0.010) at 1 week postoperative and with baseline SFCT at all postoperative visits (all P < 0.05).

Choroidal thickness may temporarily increase following vitrectomy at the early postoperative period and subsequently decrease to the baseline value. Compared to the ERM group, the MH group showed location-dependent choroidal thickness change at early postoperative period, which might be explained by position-dependent tamponading effect of gas.