SUMMARY
The Hispanic population is underserved and underrepresented in health care. Epidemiological studies are crucial for providing insight to identify disparities and unmet eye health needs in this vulnerable group. The purpose of our study is to examine the prevalence of ocular conditions in the elderly Hispanic population in North Texas and identify the frequency in which these conditions were undiagnosed. This study was ancillary to the Health and Aging Brain study among Latino Elders (HABLE). Seventy-three HABLE participants (aged > 50 years) underwent neuropsychological evaluation and an eye health screening at the University of North Texas Health Science Center study site. Descriptive analyses were performed for prevalence of ocular conditions, as well as a comparison of self-reported conditions and ocular findings. Our results suggest the prevalence patterns for undetected ocular disease in the Hispanic population of North Texas are comparable with the epidemiological trends for this population group in other concentrated areas in the United States.
INTRODUCTION
Despite constituting the fastest growing minority population in the United States (US), Hispanics remain vastly underserved and endure significant health disparities from the majority of the US population. Hispanics represent 18.1% of the nation’s total population, as identified in the 2017 census.1 Texas claims the second largest Hispanic population in the US: 39.4% of its total population, with Mexican-Americans representing 88% of that total.1
Widespread disparities in health outcomes are persistent in the Hispanic population. In comparison to non-Hispanic whites (NHWs), Hispanics have a higher risk of serious health conditions including stroke, diabetes, and obesity.2 Evidence also points to a disparity in undetected eye diseases,3–7 and Hispanics bear one of the highest prevalence rates of visual impairment accompanying eye disease in the US.8 Unfortunately, the Hispanic population faces considerable access barriers to health care; disproportionate rates of uninsured individuals and underutilization of health care in this population are substantial contributing factors.9 Recent work suggests significant factors influencing the underutilization of eye care in the Hispanic population include: cost of care, unawareness of the value of preventative ocular health, and barriers to accessing health care professionals.9 Tailored public health interventions are warranted within this growing minority population in an effort to reduce the occurrence of undetected eye disease and improve the overall health of the nation. Ocular conditions associated with advanced age, combined with an at-risk ethnic group, pose as a serious threat to visual function and quality of life. The inextricable link between systemic health conditions related to aging and ocular conditions led to the development of the supplemental eye health screening, with the purpose of determining the prevalence of ocular conditions and comparing the consistency between self-reported conditions and ocular findings among the subset of Hispanics in our existing cohort.
METHODS
Data were obtained through an ancillary study of the Health and Aging Brain study among Latino Elders (HABLE), an ongoing epidemiological study of cognitive aging among community-dwelling Hispanic individuals age 50 or older. The HABLE study, conducted since 2012, enrolls participants utilizing a community-based participatory research approach, by connecting with and engaging communities throughout the research process. Recruitment was targeted in Tarrant County zip-code areas with the highest density of Hispanic individuals and consisted of certified community health workers delivering community presentations, brochures, door-to-door and snowball recruitment, as well as newspaper advertisements. This research was conducted under a UNTHSC IRB 2012-083 approved protocol with each participant providing written-informed consent.
Participants in the HABLE study undergo a comprehensive interview, detailed neuropsychological testing, medical examination, and fasting blood draw for clinical lab panels and inflammatory biomarkers. A total of 73 HABLE study participants completed eye health screenings conducted by adjunct faculty optometrists. The eye health screening included: self-reported ocular history, visual acuity (VA), autorefraction, slit lamp examination, pupil and ocular motility assessment, confrontation visual field, color vision, and posterior segment photographic imaging using a Canon CR-2 AF Digital Non-Mydriatic Retinal Camera. Participants were not dilated during the screening and were provided with a letter detailing the results of their eye screening. Additionally, participants could request a letter to be mailed to their doctor. All participants were provided with a list of low-cost community resources for glasses and eye health follow-up care, if indicated.
Ocular conditions that were studied in this subset include diabetic retinopathy (DR), reduced best-corrected VA, hypertensive retinopathy, cataracts, pseudophakia, dry eye disease, and clinical glaucoma risk factors. Reduced VA was defined as monocular VA of 20/40 or worse at distance or near. The threshold of 20/40 for VA was determined because it represents the legal driving standard in most states, including Texas. Patients identified as having clinical glaucoma risk factors had one or more of the following changes: enlarged cup-to-disk (C/D) ratio, C/D asymmetry, nerve fiber layer defects, and/or optic nerve rim thinning. Descriptive analyses were performed for prevalence of ocular conditions, as well as a comparison of self-reported ocular conditions and ocular findings during the eye health screening.
RESULTS
Seventy-three HABLE participants (53 women, 20 men) agreed to participate in the eye health screening; of those, all were enrolled in the ancillary study. Table 1 summarizes participant demographic information. All individuals were age 50 or older; the mean age was 63.3 (SD = 7.9). All 73 participants identified as Hispanic, with 55 confirmed as Mexican Americans. The average years of education completed by participants was 8.7 years (SD = 4.5). Of the participants, 6 (8.2%) self-reported heart disease, 25 (34.2%) reported diabetes, 35 (47.9%) reported hypertension, and 45 (61.6%) reported high cholesterol.
Table 1.
Demographic Information
| Characteristics | n (%) | |
|---|---|---|
| Total participants | 73 | |
| Males | 20 (27.4) | |
| Females | 53 (72.6) | |
| Age (in years) | Mean | 63.3 ± 7.9 |
| Median | 62 | |
| Range | 51-83 | |
| Education (in years) | Mean | 8.7 ± 4.5 |
| Median | 8 | |
| Range | 2 - 18 | |
| Self-reported health conditions | Diabetes | 25 (34.2) |
| Hypertension | 35 (47.9) | |
| Hypercholesterolemia | 45 (61.6) | |
| Heart disease | 6 (8.2) | |
| Smoking | Current smoker | 2 (2.7) |
| Former smoker | 20 (27.4) |
The prevalence of ocular conditions in the subset of participants are presented in Table 2. As can be seen, 94.5% of the participants experienced decreased monocular VA (20/40 or worse) at either distance or near, or both. More specifically, 28.8% of individuals were 20/40 or worse at distance. VA was measured with correction if the subjects had glasses or contacts, otherwise was taken uncorrected. Moreover, cataracts affected 69.9% of participants; these lenticular changes are likely a significant contributor to the high prevalence of the observed reduced VA. Table 2 also demonstrates the prevalence of DR (7 [9.6%] overall), hypertensive retinopathy (11 [15.1%]), pseudophakia (8 [11%]), and dry eye disease (32 [43.8%]). Overall, 20 participants (27.4%) exhibited glaucoma risk factors, encompassing enlarged C/D ratio (10 [13.7%]), C/D asymmetry (13 [17.8%]), nerve fiber layer defects (3 [4.1%]), and optic nerve rim thinning (7 [9.6%]). Peripapillary atrophy (PPA) is a non-specific finding that represents poor retinal function near the optic nerve and is frequently associated with age-related macular degeneration and glaucoma; 35 (47.9%) participants were identified to have some degree of PPA.
Table 2.
Prevalence of ocular conditions in Hispanic North
| Clinical Characteristics | ||
|---|---|---|
| Visual acuity >= 20/40 | ||
| Distance | 21 | (28.8%) |
| Near | 48 | (65.8%) |
| Diabetic retinopathy | 7 | (9.6%) |
| Mild | 4 | (5.5%) |
| Moderate | 1 | (1.4%) |
| Severe | 0 | (0.0%) |
| Proliferative | 2 | (2.7%) |
| Hypertensive retinopathy | 11 | (15.1%) |
| Glaucoma risk (total) | 20 | (27.4%) |
| Enlarged cup-to-disc (C/D) ratio | 10 | (13.7%) |
| C/D asymmetry | 13 | (17.8%) |
| Nerve fiber layer defects | 3 | (4.1%) |
| Nerve rim thinning | 7 | (9.6%) |
| Peripapillary atrophy | 35 | (47.9%) |
| Cataract | 51 | (69.9%) |
| Pseudophakia | 8 | (11.0%) |
| Dry eye disease | 32 | (43.8%) |
Undetected ocular disease was evident in regard to cataracts and glaucoma. Of the 59 individuals with cataracts, only 2 self-reported as having a known diagnosis of cataracts (96.6% undetected). Of the 20 individuals identified as having glaucoma risk factor(s), only 3 reported a known diagnosis of glaucoma or glaucoma suspect (85% undetected). In addition, of the 25 self-reported diabetics, 7 (28%) showed clinical signs of DR, and of the 35 self-reported hypertensive participants, 11 (31.4%) showed clinical signs of hypertensive retinopathy.
DISCUSSION
This study examined the prevalence of ocular conditions and undetected ocular disease among Hispanic elders in the North Texas region. The results are consistent with mounting evidence that Hispanics have high rates of undetected ocular disease, as demonstrated in the discrepancy between self-reported conditions and clinical findings. Additionally, the results support the high prevalence of ocular and visual conditions within this population. Our findings suggest that Hispanics in North Texas may have a higher prevalence of reduced VA, glaucoma and cataracts compared to Hispanics residing in other regions of the US.
Glaucoma is the leading cause of irreversible blindness worldwide,12 and with the rapid growth of the Hispanic population, it is predicted that by 2035, Hispanic/Latino men will be the largest US subpopulation with primary open-angle glaucoma (POAG).13 The Los Angeles Latino Eye Study (LALES) uncovered the prevalence of OAG to be 4.74% among their Latino participants,4 which surpasses the overall national 2.1% prevalence of OAG defined in the Beaver Dam Eye Study.14 We identified 27.4% of our participants to be at-risk for glaucoma, which is slightly higher yet comparable with the 25% prevalence of glaucoma suspects identified in a previous community-based study, which also noted that Hispanics/Latinos were more likely to be referred for a glaucoma evaluation than NHWs.15 Further, the LALES study revealed 75% of Latinos with OAG and ocular hypertension were previously undiagnosed,4 which was comparable with the 85% in our study. Future longitudinal studies with larger sample sizes are needed in order to determine the discrepancy in OAG prevalence among Hispanics in different geographical regions of the country.
Compared to NHWs, Mexican-Americans have higher reported rates of vision loss, and the majority of those with vision impairment would improve with optical correction.16 This is particularly important because visual function serves as an important predictor of health and quality of life.17 It has been previously determined that older Hispanics have a high prevalence (19.5%) of cataractous lenticular changes.4 Our results demonstrate a higher prevalence of cataract (68.9%) among the Hispanic North Texas population. It is important to note the LALES study included participants age 40 and over, while our study population encompassed an older cohort, age 50 and older. Although there is no clear explanation for the observed differences, it is possible that the link between ultraviolet (UV) light exposure and cataract formation, coupled with increased UV indices in Texas, can account for some of the variation observed.18 The exceptionally high prevalence of undiagnosed cataract (96.6%), highlights the need to develop effective educational tools and resources for Hispanics.
To the best of our knowledge, little research has been conducted analyzing the epidemiology of ocular disease among the Hispanic population in Texas, particularly North Texas. Tarrant County, the location of our study, accounted for the most rapid growth of Hispanic residents in Texas, making it an ideal location to conduct such studies.19 The present study sample was community-based rather than a clinic-based sample, which is advantageous as it is likely a better depiction of prevalence rates. Our findings corroborated preceding studies that have identified Hispanics to have high prevalence of OAG risk, cataracts, and DR.4–6
There are limitations of the current study. First, the sample size is small, and the results must be validated in independent cohorts and larger sample sizes. Second, due to the supplemental nature of our eye screening, a comprehensive glaucoma workup was not performed and therefore a definitive diagnosis for glaucoma was not made. Lastly, the present study relied on self-reporting of ocular history, which is subject to recall bias.
In conclusion, there is an imminent need to combine such data with identified barriers to accessing care to help establish and enhance culturally sensitive intervention strategies. Continuation of this study will focus on examining additional participants of this population, recruitment of NHW participants to improve examination of disparities and correlating available biomarkers and indicators of systemic and mental health with ocular findings.
Acknowledgements:
This study was partially funded by philanthropic support to the North Texas Eye Research Institute (NTERI) at the University of North Texas Health Science Center (UNTHSC) and a seed grant from the Institute of Healthy Aging at UNTHSC. Research reported in this publication was supported by the National Institute on Aging of the National Institutes of Health under Award Numbers R56AG054073 and R01AG051848. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health. We would like to thank the HABLE participants and Fort Worth community for supporting this study.
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