Bridging the Gap: Geographic Disparities in Access to Diabetic Retinopathy Care Across the United States

Highlight

1. Diabetic retinopathy (DR) care, both diagnostic and therapeutic, is predominantly concentrated in urban practice locations across the United States.

2. Even after adjusting for population size and disease burden, non-urban areas contribute minimally to DR care procedures.

3. Non-urban residents exhibit higher severity of disease (higher proliferative diabetic retinopathy prevalence) yet face substantial barriers to receiving treatment locally, with most care accessed in urban centers.

4. Discontinuities in care, notably diagnostic imaging gaps, disproportionately affect older, Black patients and those with lower household incomes, suggesting health equity concerns.

Study Background

Diabetic retinopathy (DR) remains a leading cause of vision impairment and blindness among adults in the United States, particularly impacting working-age and older populations. With the rising prevalence of diabetes mellitus, the burden of DR is escalating, necessitating effective screening, timely diagnosis, and appropriate therapeutic intervention to prevent vision loss. Despite advances in treatment, disparate access to eye care services persists, especially between urban and non-urban (rural and suburban) populations. Understanding the geographic distribution of DR-related healthcare utilization is critical to shaping policies and resource allocation to reduce vision-related morbidity and health inequities.

Study Design

This retrospective cohort study utilized the American Academy of Ophthalmology’s IRIS® Registry—the largest clinical database of ophthalmology patients in the United States—to analyze patterns of DR care from January 1, 2013, through December 31, 2024. Patients had to have at least two International Classification of Disease (ICD) codes for DR and were excluded if they had concurrent ocular conditions requiring similar treatments to avoid confounding.

DR care was classified into therapeutic procedures—intravitreal injections (IVI), panretinal photocoagulation (PRP), focal laser photocoagulation (FLP), and pars plana vitrectomy (PPV)—and diagnostic procedures including optical coherence tomography (OCT), fundus photography (FP), and fluorescein angiography (FA). Procedure volumes were analyzed by urban versus non-urban practice locations, defined according to U.S. Department of Agriculture Rural-Urban Commuting Area (RUCA) codes. Further analyses adjusted for differences in local population size and disease burden to evaluate access disparities. Physician subspecialty and practice-level utilization patterns were also assessed.

A sub-analysis focused on non-urban residents, examining DR disease severity—especially proliferative diabetic retinopathy (PDR) prevalence—care adherence (gaps in OCT usage), and diabetic macular edema (DME) management stratified by urbanization of treating practices and sociodemographic variables such as age, race, and household income.

Key Findings

The study identified over 11 million therapeutic and nearly 36 million diagnostic procedures performed on more than 1.1 million DR patients. Key findings include:

• Concentration of Care in Urban Centers: Between 95 to 99% of all DR-related procedures were performed in urban practices. When adjusting for population and disease prevalence, urban locations still accounted for 65 to 90% of procedures, indicating a persistent urban dominance in DR care accessibility.
• Limited Non-Urban Practice Contributions: Non-urban sites contributed only 1 to 35% across various diagnostic and therapeutic categories. This suggests limited availability or utilization of DR care services in rural and suburban regions.
• Diverse Provider Profiles: In non-urban settings, comprehensive ophthalmologists provided more than 35% of intravitreal injections and panretinal photocoagulation treatments, compared to only 5-7% by such practitioners in urban areas—where subspecialists predominantly deliver these interventions.
• Referral Patterns and Patient Movement: Despite living in non-urban areas, over 93% of non-urban patients received therapeutic procedures in urban practices, highlighting substantial travel and potential access barriers for rural residents.
• Disease Severity and Therapeutic Use: Non-urban residents had significantly higher PDR prevalence (18.21%) than urban counterparts (16.02%) and correspondingly higher therapeutic procedure rates, indicating a more severe disease burden outside urban centers.
• Care Discontinuity: Nearly half of patients receiving care at urban practices experienced a greater than one-year gap in OCT imaging, a key diagnostic tool, compared to 44.1% in non-urban care settings. This disparity in care continuity disproportionately affected older adults, Black patients, and individuals with lower household incomes, underscoring systemic inequities.

Expert Commentary

This robust analysis provides compelling evidence of the significant geographic disparities in access to diabetic retinopathy care across the United States. The predominant concentration of specialized DR services in urban centers likely reflects underlying disparities in ophthalmologist distribution, infrastructure availability, and health system organization. The elevated PDR prevalence in rural populations may relate to delayed diagnosis, limited routine screening, and socioeconomic factors. The finding that comprehensive ophthalmologists fill the therapeutic void in non-urban areas highlights the essential role of general ophthalmic providers in bridging care gaps.

However, these patterns of care concentration and patient travel burdens highlight critical health equity issues. Barriers such as longer distances, transportation challenges, and fewer local specialists likely contribute to delayed or fragmented care, perpetuating worse outcomes in vulnerable populations. The documented care discontinuities in diagnostic imaging further emphasize the need for interventions focused on follow-up adherence, especially among socioeconomically disadvantaged groups.

Limitations inherent to registry-based retrospective studies include potential coding inaccuracies and unmeasured confounders affecting care-seeking behavior. Additionally, while the IRIS Registry captures a large volume of data, it may underrepresent certain populations not participating in ophthalmology-specific networks.

Future initiatives might explore teleophthalmology, mobile screening units, and incentivizing specialist distribution to rural areas as strategies to enhance geographic equity in diabetic eye care.

Conclusions

This comprehensive nationwide analysis establishes that diabetic retinopathy diagnostic and therapeutic services are predominantly urban-centric in the United States, even after adjusting for demographic and disease-related factors. Non-urban residents bear a higher burden of severe DR yet face significant challenges accessing timely care locally. Targeted strategies to improve geographic equity in DR management—such as expanding specialized care access, supporting non-urban ophthalmologists, and addressing sociodemographic disparities in care continuity—are urgently needed to reduce vision loss disparities and optimize outcomes among all affected populations.

Policymakers, healthcare providers, and professional societies should collaborate to design and implement interventions aimed at dismantling geographic barriers and promoting comprehensive, equitable eye care delivery across diverse U.S. communities.

Funding and Clinical Trial Registration

Funding sources and clinical trial registrations related to this registry-based analysis were not detailed in the publication.

References

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