Nailfold Hemorrhages in Primary Open-Angle Glaucoma: Systemic Differences in African American and Caucasian Patients

Abstract

Purpose : Primary open-angle glaucoma (POAG) is a leading cause of blindness worldwide and remains without known cause. Compared with other ethnic/racial groups in the Unites States, African Americans are at the highest risk for POAG, develop the disease earlier, and experience worse outcomes. Our laboratory previously reported that systemic nailfold capillary hemorrhages are increased in POAG and correlate with visual field (VF) loss, suggesting that nailfold capillary microscopy is useful for assessing risk for POAG. The purpose of this study was therefore to determine whether systemic microvascular abnormalities including nailfold hemorrhages, dilated capillaries, and avascularity were more prevalent or severe in African American POAG patients compared with Caucasian POAG patients.

Methods : Caucasian POAG (n=120) and control (n=194) subjects and African-American POAG (n=82) and control (n=54) subjects were recruited from four sites with IRB approval. Videos were recorded from the fourth and fifth digit of the non-dominant hand using a JH-1004 capillaroscope at 280X magnification. The presence of hemorrhages, dilated capillaries, and avascular zones was assessed by two masked observers and normalized to per 100 capillaries. Significance was determined by Mann–Whitney U test; p<0.05 was considered statistically significant.

Results : Nailfold hemorrhages were increased in POAG patients compared with control subjects (p<0.0001) and in African American POAG patients compared with Caucasian POAG patients (p=0.025). The association between the presence of POAG and ≥2 hemorrhages/100 capillaries was greater in African-Americans (OR=3.05, p=0.002) than Caucasians (OR=2.07, p=0.01). Amongst POAG patients, African Americans were significantly more likely to have ≥2 hemorrhages/100 capillaries (OR=1.85, p=0.04). Hemorrhages and VF loss were positively correlated in both groups and, when compared at each VF loss classification, African American POAG patients with mild VF loss had significantly more hemorrhages (p=0.04).

Conclusions : Nailfold hemorrhages are increased, more prevalent, and develop earlier in African-American compared with Caucasian POAG patients, supporting the idea that systemic manifestations in POAG manifest differentially in racial/ethnic groups. Nailfold hemorrhages are a useful biomarker indicative of an altered coagulation state in POAG.

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