QUANTITATIVE ASSESSMENT OF THE FOVEAL AVASCULAR ZONE USING OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY BEFORE AND AFTER SURGERY FOR IDIOPATHIC EPIRETINAL MEMBRANE.

PURPOSE To investigate, using optical coherence tomography angiography, the foveal avascular zone (FAZar), the FAZ perimeter (FAZp), the acircularity index of the FAZ (FAZai), and the density of vessels surrounding the FAZ (FAZvd) before and after idiopathic epiretinal membrane surgery, and associations of these parameters with postoperative best-corrected visual acuity, letter score gain, and central foveal thickness. METHODS We retrospectively reviewed preoperative and postoperative (sixth month) medical records of 28 eyes of 28 patients who undergone epiretinal membrane surgery and had an intact ellipsoid zone. RESULTS There were significant increases in best-corrected visual acuity, FAZar, and FAZp and decreases in central foveal thickness and FAZai (all P < 0.05). Postoperative best-corrected visual acuity was not significantly correlated with any preoperative parameters. Postoperative letter score gain and central foveal thickness correlated negatively with preoperative FAZar and preoperative FAZp (all P < 0.05). Multivariable linear regression analysis revealed that preoperative FAZp was independently associated with postoperative letter score gain (P < 0.05). CONCLUSION The FAZ enlarges and becomes more circular after epiretinal membrane surgery. Postoperative best-corrected visual acuity is not associated with any FAZ parameters. In eyes with an intact foveal ellipsoid zone, especially a smaller preoperative FAZp is associated with more postoperative letter score gain.