Evaluating Access to Eye Care in the Contiguous United States by Calculated Driving Time in the United States Medicare Population

Abstract

Purpose To quantify the proximity to eye care in the contiguous United States by calculating driving routes and driving time using a census-based approach. Design Cross-sectional study based on United States (US) census data, Medicare payment data, and OpenStreetMap. Participants 2010 US census survey respondents older than 65 years. Methods For each state in the United States, the addresses of all practicing ophthalmologists and optometrists were obtained from the 2012 Medicare Provider Utilization and Payment Data from the Centers for Medicare and Medicaid Services (CMS). The US census data from 2010 then were used to calculate the geo-location of the US population at the block group level and the number of people older than 65 years in each location. Geometries and driving speed limits of every road, street, and highway in the United States from the OpenStreetMap project were used to calculate the exact driving distance and driving time to the nearest eye care provider. Main Outcome Measures Driving time and driving distance to the nearest optometrist and ophthalmologist per state. Results Driving times for 3.79×107 persons were calculated using a total of 3.88×107 available roads for the 25 508 optometrists and 17 071 ophthalmologists registered with the CMS. Nationally, the median driving times to the nearest optometrist and ophthalmologist were 2.91 and 4.52 minutes, respectively. Ninety percent of the population lives within a 13.66- and 25.21-minute drive, respectively, to the nearest optometrist and ophthalmologist. Conclusions While there are regional variations, overall more than 90% of the US Medicare beneficiary population lives within a 30-minute drive of an ophthalmologist and within 15 minutes of an optometrist.

Reply

“…TO THE EDITOR: Lee et al 1 state, "Our findings contrast with the results of Gibson, 2 who analyzed 3143 counties in the United States and found that 24.1% of the counties were in the lower 2 quartiles of ophthalmologist availability but in the upper 2 quartiles of optometrist availability." Gibson 2 created population-weighted quartiles of the county-level number of ophthalmologists per capita and the county-level number of optometrists per capita.…”

“…Lee et al 1 maintain that "this method of analysis grossly underestimates availability." This letter argues that Lee et al 1 did not support these assertions and notes that it has not been established that driving time to the closest eye care provider, the measure of provider availability used by Lee et al, 1 is a better predictor of vision health outcomes than other measures of the availability of eye care providers.…”

Refractive error in underserved adults

“…Lack of access to eye care providers has be attributed to workforce limitations and poor integration of optical services into existing eye care services. (7) While US eye care providers have been shown to be within reasonable drive times from patients’ homes,(27, 28) areas of the developing world have a great shortage of eye care providers who are often restricted to urban centers which limits accessibility. (7)…”

Differences in Characteristics of Medicare Patients Treated by Ophthalmologists and Optometrists

“…5 Not surprisingly, the geographic distribution of ophthalmologists and optometrists is not uniform within states, which has led some observers to argue that regional access problems exist for the provision of some services and the performance of some procedures. 5,6 Over the last several years, some states have expanded optometric scope of practice, ostensibly to improve patients' access to eye care. Newly granted privileges include laser photocoagulation and photoablative procedures, intraocular injections, and eyelid surgeries.…”

“…5 Data showing that these expanded privileges have improved patients' access to care is lacking and some recent studies have concluded that access to care has not changed in states such as Oklahoma that have allowed optometrists to perform laser procedures. 5,6,7,8 Additionally, data showing that expanded privileges have enabled patients with more advanced eye diseases and higher risks of vision loss to increasingly obtain care from optometrists is also lacking. To better guide those state legislatures that are considering expanding privileges of optometrists and other non-ophthalmologists, it is critical to understand the characteristics of patients who seek care from ophthalmologists and optometrists.…”