Association Between Geographic Distribution of Eye Care Clinicians and Visual Impairment in California.

Importance: The association between availability of eye care clinicians and visual impairment, a condition presenting with increased morbidity and health care costs, has not been thoroughly studied.

Objective: To examine associations between the geographic distribution of eye care clinicians and visual impairment in California.

Design, Setting, And Participants: This survey-based cross-sectional study included ophthalmologists and optometrists licensed in California in 2018 and 2020 as well as respondents to the 2014 to 2018 American Community Survey (ACS) by California counties and Medical Service Study Areas (MSSAs). Data were analyzed from August 2020 to December 2021.

Main Outcomes And Measures: Prevalence of visual impairment by county and MSSA.

Exposures: The number of eye care clinicians was determined based on the number of member ophthalmologists of the American Academy of Ophthalmology in 2018 and optometrists listed in the 2020 Blue Book of Optometrists in California. The prevalence of visual impairment was determined using questionnaire data from the American Community Survey. Linear regression was used to assess multivariable associations between number of eye care clinicians and visual impairment by MSSA.

Results: A total of 30 068 581 California residents were included; 15 253 655 (50.7%) were female, and 5 314 389 (17.7%) were 65 years and older. The overall number of eye care clinicians was 22.18 clinicians per 100 000 residents. The overall prevalence of visual impairment was 2411.07 residents with visual impairment per 100 000 residents. San Francisco County had the highest number of eye care clinicians per 100 000 residents (39.24 clinicians per 100 000 residents). Four counties had no eye care clinicians (Alpine, Mariposa, Inyo, and Sierra counties). For every increase of 1 eye care clinician per 100 000 residents, there was a mean (SE) decrease of 3.90 (1.39) persons with visual impairment per 100 000 residents in adjusted analyses.

Conclusions And Relevance: In this cross-sectional study, a higher number of eye care clinicians was potentially associated with lower prevalence of visual impairment in California. Additional studies are needed to assess eye care clinician availability on a national and global scale and strategies to improve access to eye care.