Foveal avascular zone in cases with epiretinal membrane or lamellar macular hole in the perioperative period

Abstract

Purpose : To evaluate foveal avascular zone (FAZ) in patients with epiretinal membrane (ERM) or lamellar macular hole (LMH) before and after surgery.

Methods : Sixty five consecutive eyes of idiopathic ERM (44 eyes) and LMH (21 eyes) were studied retrospectively. Micro incision vitrectomy surgery was performed by one surgeon from December 2015 to March 2017. After vitrectomy, both the internal limiting membrane (ILM) and ERM were removed for ERM patients. For LMH patients, the ILM around fovea was removed, but the lamellar hole-associated epiretinal proliferation (LHEP) was not removed and left around fovea. The LHEP was inverted to fill in a lamellar hole. Neither gas nor air was used for tamponade. Optic coherence tomography angiography images were captured with RTveu1000^TM (Optoveu Inc. CA) and the FAZ areas of superficial capillary plexus were measured using ImageJ (NIH). FAZ area, best collected visual acuity (BCVA) and central macular thickness (CMT) were measured before the surgery and 1, 3 and 6 months after the surgery.

Results : In ERM patients, the FAZ area was 0.182 ± 0.105 (mean ± standard deviation) mm² before the surgery and it reduced significantly at 1 and 3 months (0.142 ± 0.068 and 0.139 ± 0.073 mm², p<0.05 and p<0.01, respectively) but not at 6 months (0.151 ± 0.086 mm², p=0.39) after the surgery. Postoperative BCVA at each following visit improved significantly compared to preoperative BCVA and CMT reduced significantly from 355 ± 92 µm to 297 ± 54 µm at 6 months after operation (p<0.01). In LMH patients, the FAZ area was 0.355 ± 0.188 mm² preoperatively and decreased to 0.296 ± 0.168 mm² at 3 months after surgery (p<0.05). Postoperative BCVA at each following visit improved significantly compared to preoperative BCVA. CMT in LHMs was 203 ± 71 µm before surgery and didn’t change statistically in the postoperative period.

Conclusions : In ERM patients, the FAZ was small and thick. Even though membranes were removed by a surgery, the FAZ area remained small or became smaller after surgery and didn’t expand in most of the cases, although the thickened CMT became thinner at 6 months. Whereas, in LMH patients, the FAZ area was preoperatively larger than the normal FAZ area, which was 0.317 ± 0.129 mm² in our preliminary study, and reduced its size at 3 months after the surgery, but the thickness was unchanged postoperatively.

This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.