Peripheral blood flow and peripapillary vessel density in exfoliation syndrome and exfoliation glaucoma: a nailfold capillaroscopy and optical coherence tomography angiography study.

Abstract

Purpose :
In this cross-sectional observational study, we measured peripheral blood flow by nailfold capillaroscopy (NFC) and peripapillary vessel density (VDPP) by optical coherence tomography angiography (OCTA), in patients with exfoliation syndrome (XFS) and exfoliation glaucoma (XFG) compared to subjects with primary open angle glaucoma (POAG), normal tension glaucoma (NTG), and controls.

Methods : Subjects with XFS (9), XFG (22), POAG (22), NTG (30), and controls (17) were recruited. Nailfold capillaroscopy (BK-XW880, Biobase, Biodustry, Shandong Co. Ltd, China) was performed on the 4^th finger of the non-dominant hand of all participants. Blood flow was calculated using the commercially available softwares (VideoPad, NCH Software, Inc. CO, USA; ImageJ, NIH, USA). Peripapillary VD was measured on all eyes of the participants using OCTA (Optovue, RTvue, Fremont, USA). Multiple linear regression analysis and Generalized Estimating Equations (GEE) with marginal model were used to analyze the data for NFC blood flow and VDPP respectively, using the STATA version 14.1 program.

Results :
Peripheral blood flow at the 4^th finger is significantly lower in XFG and NTG vs. controls (p=0.002 and p=0.006 respectively) and XFG vs. POAG (p=0.046). All other intergroup comparisons showed no significant difference (p>0.05). After correction for age and BMI, no statistically significant difference was found between the aforementioned groups. Average whole VDPP was not statistically different between XFS and XFG in comparison with NTG, POAG and controls (p>0.05), before and after correction for age and BMI.

Conclusions :
Our study shows that patients with XFG have significantly lower peripheral blood flow of the nailfold at the 4^th finger when compared with controls and POAG cases, though this significance fades when results are corrected for age and BMI. Average whole VDPP does not differ between XFS, XFG, NTG, POAG and controls. A larger sample size with age-matched cases are needed to comprehensively evaluate the blood flow and VDPP in XFS and XFG patients when compared with NTG, POAG and controls.

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

 

Enface images in XFG (upper) vs. control (lower) as seen by OCTA.

 

NFC images of XFG and control.