Swept-Source OCT-Angiography of the Anomalous Foveal Avascular Zone

Abstract

Purpose : To analyze anomalous appearing (vascularized) foveal avascular zones (FAZ) using swept-source OCT-angiography (SS-OCTA) and compare these findings to the contour of the corresponding foveal pit using swept-source OCT (SS-OCT).

Methods : 14 eyes with anomalous FAZs from 10 patients were identified using SS-OCTA (Topcon Triton; Tokyo Japan). Patient demographic, visual acuity and ophthalmological diagnoses were obtained from medical records. SS-OCT imaging was used to characterize the foveal contour and identify the presence of fovea plana. Each of the vascular layers in the retina (superficial capillary plexus (SCP), deep capillary plexus (DCP) and choriocapillaris) were evaluated for both affected and unaffected eyes using the 3.0mm x 3.0mm strategy. Depth-decoded images were examined to identify anastomosis between the SCP and DCP in all eyes.

Results : 6 out of 10 patients had an anomalous FAZ findings in only 1 eye, while the remaining 4 patients had bilaterally anomalous FAZ presentations. The FAZ was absent in all 14 eyes at the level of the SCP. 5 eyes demonstrated complete vascularization of the FAZ at the DCP in addition to the SCP. The choriocapillaris was normal in all eyes. 50%(7) of eyes with a vascularized FAZ demonstrated a foveal plana configuration on SS-OCT, while 50%(7) had a normally developed pit. 4 of 10 patients had anomalous FAZ presentations bilaterally, and 2 patients with single eye involvement had a partial FAZ in their uninvolved eye. Mean ETDRS BCVA was 0.20 ± 0.14 logMAR units for anomalous FAZ eyes, and 0.20 ± 0.15 logMAR units for uninvolved eyes for patients with single eye involvement.

Conclusions : The FAZ is a key anatomical landmark which can be imaged successfully using SS-OCT-angiography. Vascularization of the FAZ is uncommon and can be found in eyes with both a normally developed FAZ as well as eyes with a fovea plana configuration and is not necessarily associated with worse vision. The SCP and DCP can both be involved in an anomalous vascularized FAZ configuration.

This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.

 

(A) Color fundus photographs and (B) Swept-source OCT images of the right and left eyes respectively. Inset of (B) demonstrates the absence of a defined foveal pit.

 

Swept-source OCT angiogram of the (A) superficial capillary plexus, (B) deep capillary plexus, and (C) choriocapillaris of the right and left eyes respectively. (A) and (B) demonstrate anomalous foveal vascularization and the absence of a foveal avascular zone.