Visual impairment and blindness are important public health problems. In 1990, the aggregated cost of blindness to the federal budget in the United States was approximately US$ 4.1 billion.
Prevalence information suggests that uncorrected refractive error, diabetes, glaucoma, and age-related maculopathy (ARM) are the most common causes of visual impairment and blindness in the United States. More specifically, diabetic retinopathy is the leading cause of permanent blindness in working adults, with ARM and glaucoma ranking as second and third leading causes, respectively.
To address these problems, the U.S. Department of Health and Human Services added the Healthy Vision 2010 objectives to the Healthy People 2010 initiative. These objectives include decreasing visual impairment due to eye disease and uncorrected refractive error and increasing regular eye exams for adults. A second objective of both the Healthy People 2010 and Healthy Vision 2010 is to decrease the disparity of poor health in racial minorities.
Vision is the second leading cause of impairment in American Indian and Alaska Native people. The AI/AN people need to know the prevalence and causes of visual impairment in their community. With this information, the AI/AN people can develop interventions to decrease the risk of visual impairment in their community. We hypothesize that telemedicine will increase access to eye exams, and correcting refractive error will improve quality of life, both objectives of the Healthy Vision 2010.
This topic was selected by the Tribal Community Advisory Committee as their top priority prevention project for the first core project.
- To determine if non-MD, non-OD paraprofessionals (such as ophthalmic technicians) performing newer methods of testing have good diagnostic precision and feasibility in comparison with an expert examiner (such as an ophthalmologist or optometrist).
- To attain preliminary data regarding the age-specific prevalence of visual impairment, blindness, and ocular disease (such as cataract, glaucoma, diabetic retinopathy, age-related maculopathy) in a sample of Northwest American Indians and Alaskan Natives (AI/AN) aged 40 years and older.
- To measure the change in quality of life (QOL) associated with uncorrected and under-corrected refractive error in AI.
- To compare telemedicine with non-mydriatic cameras to current surveillance methods for sensitivity to detect progressive diabetic retinopathy.
Our community research partners include three tribes in the Northwest and an urban clinic in the mid-west with a large American Indian patient population.
Our ophthalmic technicians gave free basic health and eye exams to randomly selected members (40 years of age or older) from three randomly selected tribes in the Pacific Northwest. All participants with suspicious findings in the preliminary exams and 1/3rd of those with normal exams were given full, dilated eye exams by our ophthalmologist. Tribal members who presented with uncorrected or undercorrected vision received free eyeglasses to determine the level of change in vision-related quality of life. We enrolled tribal members with diabetes in a telemedicine study in which retinal photos are taken without dilation and sent to the Devers Eye Institute’s reading center for review.
Basic health examinations included measurement of blood pressure and blood glucose (hemoglobin A1C) readings. We measured quality of life using the 25-item National eye Institute Visual Functioning Questionnaire (NEI-VFQ 25). We assessed health behaviors using the Behavioral Risk Factor Surveillance System (BRFSS)
In the eyeglasses study, we asked participants to complete the NEI-VFQ 25 prior to receiving a free pair of eyeglasses. We gave the NEI-VFQ 25 again to participants within 1-3 months later, and we compared the scores between these two questionnaires to determine any differences between those with impairment and those without, and also to determine what changes in vision-related quality of life occurred after best-correction.
The telemedicine study uses state-of-the-art technology to record and transfer retinal images. We examine participants using a non-mydriatic camera, which takes fundus photos without need for dilation. Our on-site technicians send these images to a reading center via a web-interface that we designed specifically for this project. This interface allows the technicians to enter clinical and demographic data, upload photos and assign their position, and send them to the Devers Eye Institute reading center for review. Trained optometrists and ophthalmologists review the images and grade the level of retinopathy and other eye diseases and send an electronic report to the participating sites. These reviews are later compared to information sent to the reading center by the participant’s eye care provider.
Prevalence and screening study
Out of 632 tribal members we selected for the study, 444 (70%) completed some or all of the study, with 414 (65%) completing all parts of the study. One hundred and eighteen (19%) tribal members agreed to participate in the study, but did not attend; 80 (13%) tribal members declined to participate in the study; and 20 (3%) had incomplete screening or questionnaire data. These data were included in the analysis where available.
The majority of participants were women (63.1% women and 36.9% men). Nearly half were between the ages of 40 and 49 years (44%). Thirty percent of tribal members were between the ages of 50 and 59 years, while 15 percent were between the ages of 60 and 69 years, and 12 percent were 70 years of age or older. Forty-two percent (42.8%) of participants reported being married, while 54.5% reported not being married. Most participants (54.3%) reported having greater than a high school education, 29.1% reported having a high school education, while 14.4% reported having less than a high school education. The majority of participants reported being employed (61.9%).
The greatest proportion of participants (40.8%) reported a household income greater than 200% of federal poverty level. Seventeen percent of participants (18.2%) reported a household income below federal poverty level. Eighteen percent of respondents, (18.0%), reported a household income between 101%-150% of federal poverty, and 14% reported an income between 151%-200% of federal poverty level. Nine percent of respondents (9.0%) declined reporting an annual household income.
The largest proportion of participants (77%) reported wearing glasses for either near vision, distance vision, or both. Seven percent of participants were found to have uncorrected or undercorrected distance vision, and nearly a quarter of all participants (24%) were found to have uncorrected or undercorrected near vision. Near vision can usually be easily and inexpensively corrected through the use of simple over-the-counter reading glasses.
Five percent of participants whose best-corrected vision was worse than 20/40 had visually significant cataracts, and 14 % of all participants had either a visually significant cataract or history of cataract surgery.
Glaucoma was found in 12% of participants, while glaucomatous features were found in 23 % of participants (right eye). Of those who had glaucoma, all (100%) had an intraocular pressure less than 22 mm Hg. The high prevalence of low-tension glaucoma in this study suggest a need for further analysis of ocular factors such as corneal thickness, intraocular pressure and optic disc characteristics in AIAN populations.
Diabetes and undiagnosed diabetes remain as significant health concerns in AI/AN communities. Twenty-one percent of participants reported having been diagnosed with diabetes, and 2.6% were discovered to have undiagnosed diabetes in this screening. Of those who reported having been diagnosed with diabetes, only 22% said they had ever had an eye exam, with most of those exams (80%) occurring within the past year.
High blood pressure and obesity are also significant health issues within the tribes. In this screening, 65 % of participants were found to have a blood pressure reading greater than 135 systolic (top number) or 85 diastolic (bottom number). Additionally, 64.2% were obese based on body mass index, and 85% of women and 92% of men were either overweight or obese based on BMI.
Another significant health problem is the high number of smokers within the screening group. Though only a third (33.5%) of the screening participants reported current cigarette smoking, 68.8% reported smoking at least 100 cigarettes in their lifetime.
Eyeglasses and Telemedicine: Studies in Progress
We continue to recruit participants for the eyeglasses and non-mydriatic camera (telemedicine) studies. Currently, we have enrolled 59% of our target sample in the non-mydriatic/telemedicine study, and 38% of our target sample in the eyeglasses study. We expect to complete recruitment for both studies by August of 2008.
Preliminary results from the eyeglasses study have shown the NEI-VFQ 25 to be a valid and reliable instrument for use in AI/AN populations. These analyses have shown a significant correlation between visual acuity and quality of life, as well as a significant improvement in quality of life scores after receiving the appropriate eyeglasses correction
Our most recent preliminary analysis of the results from the telemedicine study found evidence of diabetic retinopathy in 4 of 106 participants imaged (4%). Future analyses of the data collected will determine the efficacy of using telemedicine to detect and monitor the progression of diabetic retinopathy and its diagnostic precision relative to that of a traditional dilated eye exam.