The Association of Scope of Practice Expansion with Changes in Optometry Workforce Density
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Importance
Access to eye care is increasingly constrained by declining ophthalmologist workforce density, particularly in rural areas, while optometrist workforce is projected to exceed demand. Numerous state legislatures have expanded optometrist scope of practice (SOP), but the workforce effects of these policies have not been evaluated.
Objective
To evaluate changes in optometrist and ophthalmologist workforce density following state-level expansion of optometrist scope of practice.
Design
This retrospective ecological study analyzed workforce density across 50 states and the District of Columbia. Between 2008–2019, nine states expanded SOPs for optometrists. We used interrupted time-series regression to estimate associations between these policy changes and provider density from 2010-2021, adjusting for covariates.
Setting
Population-based analysis of all 50 US states and the District of Columbia, 2010–2021.
Participants
State-level workforce data were derived from Bureau of Labor Statistics and US Census data (optometrists) and the American Medical Association Physician Masterfile (ophthalmologists). Socioeconomic covariates were obtained from the American Community Survey.
Exposure
State-level legislative expansion of optometrist SOPs to allow injections beyond anti-anaphylaxis treatment, lesion removal, and/or laser procedures. SOP changes were identified through systematic review of legislative and regulatory records.
Main Outcomes and Measures
Annual change in optometrist and ophthalmologist workforce density (providers per 100,000 population) following SOP expansion, adjusted for age, income, rates of vision difficulty, diabetes, poverty, and uninsured status.
Results
Nine states met inclusion criteria for SOP expansion between 2008 and 2019. Analysis of national data showed that among all 50 US states and the District of Columbia, SOP expansion was associated with a non-significant change in optometrist density (−0.65 per 100,000; 95% CI, −1.87 to 0.57) and ophthalmologist density (+0.09; 95% CI, −0.10 to 0.28). Results were consistent in the 9-state subgroup (optometrists: −0.60, 95% CI −2.90 to 1.70; ophthalmologists: +0.02, 95% CI −0.13 to 0.18).
Conclusions and Relevance
Our population-level data suggest that, in the US, state legislation expanding optometrist scope of practice has not been associated with increased workforce density. As numerous state legislatures continue to consider such policies, these findings can inform efforts to balance access to eye care with patient safety.
Key Points
Question
Does expanding optometrist scope of practice (SOP) increase optometrist workforce density in adopting states?
Findings
In this retrospective ecological interrupted time-series study of all 50 US states and the District of Columbia (2010–2021), SOP expansion in 9 states was not associated with a significant change in optometrist or ophthalmologist workforce density.
Meaning
Expanding optometrist SOP was not associated with increased workforce density in states that adopted such policies, suggesting that SOP expansion alone may be insufficient to address geographic shortages in eye care access. These findings should be considered by state legislators weighing scope of practice expansion as a workforce solution.
