Retinal vascular geometry and glaucoma: the Singapore Malay Eye Study

Abstract

Purpose: To determine the associations of geometric measurements (tortuosity, branching angle, and fractal dimension) of retinal vessels with glaucoma.

Design: Population-based, cross-sectional study.

Participants: Persons aged 40 to 80 years who participated in the Singapore Malay Eye Study (n=3280; 78.7% response rate).

Methods: Quantitative retinal vascular parameters (tortuosity, branching angle, and fractal dimension) were measured from digital retinal fundus photographs using a computer-assisted program following a standardized grading protocol. Glaucoma was diagnosed according to the International Society of Geographic and Epidemiological Ophthalmology classification system.

Main outcome measures: The associations among retinal vascular parameters with glaucoma, the main glaucoma subtype primary open-angle glaucoma (POAG), and ocular hypertension (OHT).

Results: A total of 123 persons (4.4% of the 2789 participants) had glaucoma in the final analysis, 87 (70.7%) of whom were diagnosed with POAG. After adjusting for age, sex, body mass index, diabetes, hypertension, smoking, axial length, and intraocular pressure (IOP), decreased retinal arteriolar tortuosity (odds ratio [OR], 1.73; 95% confidence interval [CI], 1.38-2.18, comparing lowest vs. highest quartiles), decreased retinal venular tortuosity (OR, 1.59; 95% CI, 1.29-1.97), and narrower retinal venular branching angle (OR, 1.22; 95% CI, 1.00-1.48) were associated with glaucoma. Similar associations were found between these retinal vascular parameters and POAG. Decreased retinal vascular fractal dimension was associated with OHT (OR 1.37; 95% CI, 1.04-1.82).

Conclusions: Certain features of retinal vascular geometry are associated with glaucomatous optic neuropathy independently of vascular risk factors and IOP.

Financial disclosure(s): The author(s) have no proprietary or commercial interest in any materials discussed in this article.