Abstract
Purpose :
POAG is a common debilitating disease without known cause. Several systemic risk factors have been implicated in POAG etiology including nailfold hemorrhages, systemic hypotension and migraine. Myopia has also been associated with POAG. The purpose of this study is to elucidate relationships between myopia, POAG and nailfold hemorrhage by modeling high myopia as an exposure variable in POAG and increased nailfold hemorrhages.
Methods :
A cross-sectional case-control study was conducted among two study sites in Chicago, Illinois (the practice of Zaparackas and Knepper Ltd. and Northwestern University, Department of Ophthalmology). POAG status, refractive error (RE) and demographic information were obtained for all enrolled POAG (n=75) and control (n=144) subjects. Only subjects myopic in at least one eye were enrolled in the study. RE ≤ -3 diopters (D) and -3 D < RE < 0 D were considered high- and low-myopic respectively. Presence of nailfold hemorrhages was determined with video capillaroscopy as described in [IOVS 2015], and expressed as a count per 100 capillaries. Subjects with ≥2 and <2 hemorrhages per 100 capillaries were considered positive and negative for significant nailfold hemorrhages respectively.
Univariate and multivariable-adjusted logistic regression analyses were conducted to investigate association between myopia and the presence or non-presence of POAG (model 1), or significant nailfold hemorrhage (model 2). Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated. Model 1 was adjusted for age, sex, race, and study site. Model 2 was adjusted for age, race and study site. All analysis was performed with SAS 9.4.
Results :
A total of 219 myopic subjects were enrolled in the study. Of the 75 POAG subjects, 23 (31%) were considered high myopic. Univariate analysis revealed slight positive, but non-significant relationships between high myopia and the presence of POAG: OR = 1.2 (95% CI, 0.6-2.2) and ≥2 nailfold hemorrhages: OR = 1.3 (95% CI, 0.7-2.4). Adjustment reveals stronger, significant relationships between high myopia and either POAG: OR = 3.1 (95% CI, 1.3-8.3, P ≤ .0250) or ≥2 nailfold hemorrhages: OR = 3.0 (95% CI, 1.4-6.6, P ≤ .0069).
Conclusions :
This study provides statistical evidence of an association between high myopia and increased odds of both POAG and nailfold hemorrhages. Thus, high myopia may be a cofactor in POAG.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.