Analysis of foveal avascular zone in diabetic eyes without retinopathy before and after small-incision phacoemulsification using optical coherence tomography angiography

Abstract

Purpose : To analyze the foveal avascular zone (FAZ) and perifoveal intercapillary area (PIA) in diabetic eyes without retinopathy in comparison to healthy eyes following small-incision phacoemulsification using spectral-domain optical coherence tomography angiography (OCTA).

Methods : Ten eyes of 10 patients with diabetes without retinopathy and 10 eyes of 10 healthy subjects (controls) underwent 3x3mm enface OCTA imaging using Cirrus high-definition Angioplex (Carl Zeiss Meditec, Inc., Dublin, CA) before they were scheduled for small-incision phacoemulsification (baseline imaging). Of these, 8 eyes of 8 diabetic patients and 8 eyes of 8 healthy subjects underwent surgery and were imaged again within one week following surgery (postoperative imaging). OCTA images were analyzed for FAZ remodeling. FAZ and PIA were quantified before and after surgery using Fiji image analysis software.

Results : Mean age of diabetic patients was 68.4 ±3.4 years and that of healthy subjects 65.6 ±4.5 years (p=0.3). FAZ remodeling was observed in 5 of 10 diabetic eyes without retinopathy (50%) and 2 of 10 healthy eyes (p=0.02) on baseline imaging. FAZ and PIA were significantly enlarged in diabetic eyes without retinopathy when compared to healthy eyes on baseline imaging (0.37±0.05 vs. 0.31±0.08mm²; p=0.04; n=10 and 0.60±0.30 vs. 0.88±0.35mm²; p=0.03; n=10 respectively). FAZ size increased on postoperative imaging when compared to baseline imaging in diabetic eyes without retinopathy (0.35±0.12 vs. 0.40±0.11mm²; p=0.01; n=8; Figure 1) but not in healthy eyes (0.31±0.09 vs. 0.32±0.10mm²; p=0.1; n=8).

Conclusions : Diabetic eyes without retinopathy have retinal microvascular changes at baseline. Small-incision phacoemulsification leads to further disruption of the retinal microvasculature in these eyes in the early postoperative period. Presence of diabetes alone even in absence of retinopathy may have potential implications in the postoperative development of macular ischemia and/or cystoid macular edema in these eyes.

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

 

3x3mm OCTA images in a diabetic eye without retinopathy before (left) and after (right) surgery showing increased FAZ size after surgery (0.34 vs. 0.38mm²; yellow drawing)