Discussion
Older adults have the highest rates of visual impairment due to age-related eye diseases and conditions like cataract, glaucoma, presbyopia, and age-related macular degeneration. Also, older patients with diabetes are at risk of developing diabetic retinopathy. Therefore, older adults, more than any other age group, need to have routine eye examinations at least every 1–2 years. Most older people who already know that they have a chronic eye disease need to be seen at least every year, if not more frequently.
To our knowledge, this is the first study to examine eye care utilization on a world-wide basis. Very few studies have examined the rate of eye care utilization in low or middle income countries. We found very low rates of eye care utilization in the world with an overall rate of only 18% of older adults having seen an eye care professional in the last year. The rate varied 4-fold depending on the income status of the country.
Prior research on eye care utilization has typically focused on high income countries like the United States, Australia, and Canada. Three studies from these high-income countries reported that 60–70% of older adults visited an eye care provider in the last year. In the WHS data, only 3 of the 20 high-income countries asked the question on eye exams (Slovenia, Spain, and the United Arab Emirates (UAE)). The rates of an eye exam in the last year in those aged 60 years and older from these three countries were 27% (unweighted), 37%, and 47% respectively. These rates are much lower than the rates seen in the United States, Australia, and Canada.
In low or middle income countries, we only found three studies that reported on this topic. In a population-based study in Tehran, Iran, an upper middle income country, 13% of adults aged 60 years and older had never seen an eye care professional. Iran did not participate in the WHS so we are unable to compare our results. In a study of people with diabetes in China, a lower middle income country, 43% of urban people and 69% of rural people had never had an eye exam. There were not enough people who reported having diabetes living in rural China in the WHS to examine this. However, 46% of urban and 85% of rural Chinese WHS participants reported never having an eye exam. In a study done in rural India, a low income country, 64% of people aged 40 years and older had never had an eye exam. In the WHS data from rural India, we found that 55% of adults aged 60 and older reported never having an eye exam. Because the same age ranges were not included, it is difficult to directly compare the results.
Certain factors were independently related to eye care utilization regardless of the income status of the country. Men had lower rates of eye exams than women. This finding is consistent with other literature. Also, those with lower education had lower rates of eye exams. This finding is also consistent with other literature. If people do not understand that vision loss is not a normal part of aging and that services may exist to correct this vision loss, they are not likely to have an eye exam. It is also possible that education is confounded with other factors that affect eye exam utilization such as income, culture, or empowerment. Independent from education, those in rural areas were less likely to have an eye exam in the last year than those in urban areas. This may be due to the difficulty in finding an eye care provider in rural areas. Other studies have also documented a lower rate of eye care utilization in rural versus urban areas. Those who were in worse self-reported health were more likely to have had an eye exam, which suggests that contact with a healthcare provider may have spurred an eye exam. Those who had diabetes were more likely to have had an eye exam in the last year although only 32% had had an eye care exam in the last year. Current recommendations are that diabetics should see an eye care professional every year. Those who wore glasses or contact lenses were more likely to see an eye care professional in the last year, which is important since refractive status can change and needs to be evaluated on a regular basis.
Those with higher income in the WHS were more likely to have an eye exam in the last year. Few prior studies have examined income. Those that did report inconsistent findings on this relationship. In China, monthly income was not associated with use of eye care services in diabetic patients. In high income countries like the United States, women with a higher income were more likely to have had an eye exam in the last 2 years. Also in the U.S., using data from the National Health Interview Survey, the probability of having a dilated eye exam in those with an eye disease increased with higher income status.
Our findings on eye care utilization are consistent with other literature showing that gender, education, and rural residence are related to health services utilization. Men are reported to use less health care services than women including general practice utilization, hypertension and diabetes treatment although men may be more likely to be hospitalized. People with less education are less likely to use preventive health services (mammogram, Pap test, dentist), maternal health care, and reproductive services. One study found that health literacy significantly mediated educational disparities in the receipt of the influenza vaccine in older adults. People living in rural areas in a variety of countries are reported to use less healthcare services including antenatal care, dental services, physician visits, and immunizations compared to people living in urban or suburban areas.
The WHS is a rich, under-utilized source of population-based data from around the world. We augmented the WHS data with data from the World Bank on the income status of the country. Most of the countries had very good response rates which allows us to calculate prevalence estimates that are representative of the entire country. Limitations of the WHS data include that we do not have comprehensive data on barriers to eye care utilization or presence of an eye disease via an eye exam. Eye care utilization is based on self-report which could lead to misclassification if participants do not have a good memory of their last eye exam. We do not know whether the participant visited an ophthalmologist/optometrist/or other medical professional. Only 78% of those aged 60 years and older answered the question on eye care utilization although 75% of this missing data came from upper middle or high income countries which simply did not administer this question. The rate of missing data for this question in low and lower middle income countries was 10% and 10% respectively. The study design is cross-sectional which prohibits us from examining trends in eye care utilization over time and from examining the temporality of the exposures and the outcome.