Geographic Distribution and Drive Times to Glaucoma Specialists in the United States: A National Geospatial Access...

Access to glaucoma specialists varies substantially across the United States, and geographic barriers may delay and limit care. Using publicly available spatial data, we estimated travel burden by calculating county-level drive times to the nearest practicing glaucoma specialist and summarized results at the state, US Census region, and rural-urban commuting area (RUCA) core-type levels.

Cross-sectional geospatial analysis SUBJECTS: County-level geographic units in the contiguous United States.

This analysis was conducted in Python 3.9.6 using US Census Bureau county-level data and practice locations of glaucoma specialists obtained from the American Glaucoma Society, limited to those with provisional or active membership practicing in the United States. County geographic centroids were linked to the nearest specialist practice location across county and state boundaries. Approximate drive times from county centroids to the closest specialist were computed, and state-, census region-, and RUCA-level summaries were generated.

Estimated drive time.

Across the contiguous 48 states, mean drive times to the nearest glaucoma specialist ranged from 0.04 hours in the District of Columbia to 3.77 hours in North Dakota, while median drive times ranged from 0.04 to 4.40 hours over the same jurisdictions. The proportion of counties with drive times below their state's mean also varied widely, from 2% in Delaware and Rhode Island to roughly 80% in Georgia, reflecting marked intrastate heterogeneity. Regional analyses showed the shortest median drive times in the Northeast (0.66 hours) and the longest in the West (1.85 hours), with the Midwest and South demonstrating intermediate medians of 1.38 hours and 1.23 hours, respectively. When stratified by RUCA core type, metro core counties had the lowest median drive time (0.23 hours), whereas small-town cores and rural counties experienced considerably longer medians (1.16 hours and 1.02, respectively).

Access to glaucoma specialists shows striking geographic disparities. Northeastern and metropolitan counties benefit from relatively short travel times, whereas western and rural counties face substantially longer drives. These findings highlight the need for targeted outreach, teleophthalmology expansion, and workforce planning to reduce geographic barriers to glaucoma care.

Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.