Cataract and Barriers to Cataract Surgery in a US Hispanic Population: Proyecto VER

Objectives  To report the prevalence of visually significant cataract and cataract surgery and to determine demographic and socioeconomic factors that influence use of cataract surgery in a US Hispanic population.

Methods  Proyecto VER is a population-based study of Hispanic individuals, 40 years or older, living in southern Arizona. Visual acuity was measured monocularly, and a dilated ophthalmic examination was performed to determine lens opacities. Visually significant cataract was defined as severe levels of opacity and acuity worse than 20/40. Risk factors were compared between those who obtained cataract surgery in the past and those having visually significant cataract.

Results  A majority of the 4774 participants in this study were of Mexican descent; 2.8% had visually significant cataract and 5.1% had undergone bilateral cataract surgery. Among those currently or previously needing surgery, having medical insurance (odds ratio, 2.88; P<.001) and speaking English (odds ratio, 1.80; P = .04) were significantly associated with having obtained surgery in the past.

Conclusions  Visually significant cataract appears to be high among US Hispanic individuals of Mexican descent, as evidenced by rates of cataract and cataract surgery. Language and financial barriers in this population impede access to surgery. Further work to remove these barriers and provide sight restoration is warranted among Hispanic individuals of Mexican descent living in the United States.

Cataract is the leading cause of visual impairment in the Hispanic community.¹ Currently, there is little information on the prevalence of cataract, cataract surgery, and factors related to obtaining cataract surgery in this population.

Other studies have looked at cataract prevalence and factors associated with obtaining cataract surgery in mainly white and African American populations. The Salisbury Eye Evaluation (SEE) Study found higher rates of cortical opacity in African American compared with white individuals but higher rates of cataract surgery in white individuals.² Javitt et al³ determined that increasing age, being white, and higher income levels were associated with obtaining cataract surgery among persons using Medicare. In the Beaver Dam Eye Study,⁴ incident cataract surgery has been linked to increasing age, 35 or more pack-years of smoking (a risk factor for progression of nuclear cataract), and baseline cataract status. The Blue Mountains Eye Study⁵ found that occupational prestige was not related to incident surgery after accounting for age, sex, steroid use, history of angina, myopia, and iris color.

Use of eye care services, while being less specific than cataract surgery, has also been linked to demographic and socioeconomic factors. The Melbourne Visual Impairment Project found that those who spoke languages other than English at home were less likely to ever have obtained eye care than those who spoke English⁶; these data suggest that acculturation may play a role in obtaining eye care services. Older age and higher educational level have also been consistently associated with obtaining eye care services in the SEE Study, Melbourne Visual Impairment Project, and Blue Mountains Eye Study.^6-8

The purpose of this study was to report the prevalence of visually significant cataract and cataract surgery and to determine demographic and socioeconomic factors that influence use of cataract surgery in a Hispanic population living in the United States.

Proyecto VER (Vision and Eye Research) is a population-based survey of visual impairment and blindness among noninstitutionalized Hispanic individuals 40 years or older living in the Pima and Santa Cruz counties of southern Arizona. A stratified random sample, which is described elsewhere,⁹ was used to select block groups in 2 major cities in Arizona: Nogales in Santa Cruz county and Tucson in Pima county. All members of sampled households who were self-described Hispanic and 40 years and older were eligible to participate.

After obtaining informed consent for participation, participants were interviewed at home by trained personnel. The interview was followed by a complete ophthalmic examination at a central clinic site. Data collection started in April 1997 and ended in September 1999. All study procedures were approved by the Johns Hopkins University Joint Committee on Clinical Investigations and followed the tenets of the Declaration of Helsinki.

The questionnaire was administered by trained personnel and offered in English and Spanish. The majority of home interviews (80%) were conducted in Spanish. The questionnaire contained specific questions on education, socioeconomic status, history of vision problems, visit to an eye care professional, and self-report of diabetes mellitus. Also included were a series of questions relating to health care use, access, and medical insurance taken from the Hispanic Health and Nutrition Examination Survey.¹⁰ An acculturation index was created by summarizing specific questions from the Hispanic Health and Nutrition Examination Survey regarding preferred language, country of birth, and other questions relating to adapting to US culture.¹¹ The acculturation score ranges from 1 to 5, where 1 is low acculturation and 5 is high acculturation.

Visual acuity was assessed at the clinic, for each eye separately. Initial acuity was measured with the participant’s habitual distance correction. best-corrected acuity was measured after a full subjective refraction, using an auto-refractor (Humphrey Auto-Refractor; Humphrey Instruments Inc, San Leandro, Calif) to determine a starting point. Distance acuity was tested with the Early Treatment Diabetic Retinopathy Study chart¹² at 3 m, illuminated at 130 candela/m². Participants who failed to read the largest letters at 3 m were retested at 1.5 m, then at 1 m. Visual acuity was scored as the total number of letters read correctly, transformed to LogMAR units.¹³ Failure to read any letters was assigned an acuity of 1.7 LogMAR units, which is equivalent to acuity of 20/1000. An E chart¹² was used for participants who were illiterate.

A standardized dilated ophthalmic examination was performed to determine the presence, type, and severity of lens opacities. Lenses were graded at the slitlamp using the Wilmer Cataract Grading Scheme.¹⁴ Nuclear opacification was graded against the standard photograph for an integer grade, with decimalized interpolation between the standards¹⁵ and a grade range from 0 to 4. Cortical opacification was estimated by dividing the pupillary area into 16 sectors and estimating the number of sectors obscured by opacity.¹⁶ Posterior subcapsular (PSC) opacity was graded as present or absent. In this article, we used severe cataract grades in conjunction with visual impairment (visually significant cataract) to describe those in need of cataract surgery.

The absence of the natural lens in either eye indicated the participant had obtained cataract surgery. If a participant had a missing lens grade, the companion eye was used to determine the opacity grade, a procedure consistent with other studies.^2,17,18 The ophthalmologist (J.R.) indicated whether the status of the aphakic or pseudophakic eye was normal, abnormal, or dislocated (pseudophakia). Reasons for abnormal outcomes included iris capture (the optic of the intraocular lens was in front of the iris), abnormal iris, or a damaged intraocular lens during capsulotomy.

Blood was drawn to determine glycosylated hemoglobin level; procedures for drawing blood have been described previously.⁹ In this article, diabetes mellitus was defined as either an affirmative answer to the question of whether diabetes mellitus had been diagnosed by a physician or having a glycosylated hemoglobin level of 7.0% or higher. All others were classified as not having diabetes mellitus.

Age-adjusted racial differences in rate of cataract and cataract surgery were made between white and African American individuals in the population-based SEE Study and Hispanic Americans in this study. Grading schemes were the same for both studies. However, the SEE Study took photographs of the nuclear, cortical, and PSC regions, and graders were unaware of the status of the fellow eye. In Proyecto VER, the ophthalmologist graded eyes at the slitlamp. The SEE Study prevalence ratios are based on data from September 1993 to September 1995.

Visually significant cataract at the person-level was categorized as a high grade of cataract and best-corrected acuity worse than 20/40 in the cataractous eye. We assumed that impaired acuity was due to the severe level of opacity, rather than to other conditions; however, we will see later that this assumption was reasonable since a majority of this group did have cataract as their primary or secondary cause of visual impairment. High grades of cataract were defined as follows: a nuclear cataract with grade 4.0 (highest grade); cortical cataract grade 8/16 or higher (approximately half the lens was obscured by opacity); or the presence of PSC. Differences in visually significant cataract and bilateral surgery between sexes were assessed using odds ratios adjusting for age.

We compared characteristics of participants who had obtained surgery in at least 1 eye with those who needed but never obtained surgery; the latter group consisted of those having visually significant cataract in at least 1 eye at the time of the examination and no evidence of surgery in either eye. Characteristics of interest included basic demographics (age, sex, income level, high school education, and location) and culture (acculturation level and spoken language). Spoken language was divided into 2 groups: those who only or mostly spoke Spanish (mostly Spanish) and those who spoke English and Spanish equally, mostly, or only English (both Spanish and English to mostly English). Other characteristics included access to medical care: having medical insurance, frequency of medical care, and type of medical care facility.

The relationship between participant characteristics and use of cataract surgery was analyzed in a multivariate logistic model that included demographic, cultural, and medical access variables. To avoid colinearity, which was significant, among the variables in the culture and medical access groupings, preferred speaking language and having medical insurance were chosen to represent their groupings in the model. All variables, except age, were included in the model as categorical variables, with categories as follows: income, $20 000 or less per year or more than $20 000 per year; education, less than a high school education or high school education or more; acculturation score, 1.33 or less, 1.34 to 2.30, or 2.31 or more; preferred spoken language, mostly Spanish or equal preference to mostly English; usual medical care, doctor’s office or clinic or emergency room or urgent care; last medical visit, less than 1 month ago, 1 month to less than 6 months ago, or 6 months or more.

Age-specific prevalence of visually significant cataract and cataract surgery in Proyecto VER was compared with similar prevalence rates in the SEE Study; this study used the same cataract-grading scheme and had comparable data on visually significant cataract and diabetes mellitus for both white and African American individuals. Racial comparisons for visually significant cataract and bilateral cataract surgery were adjusted for age, sex, and diabetes mellitus status.

A total of 4774 subjects (72%) participated in the interview and examination. Eligible persons not participating in this study have been described previously.¹ In brief, nonparticipants were in the youngest or oldest age categories, and women participated more often than men. Those with self-report of low-vision status were more likely to participate, adjusting for age and sex. Although all self-described Hispanic persons were eligible, a majority were of Mexican descent, with more than 90% of participants having at least 1 parent born in Mexico.¹

Of the 4774 participants in the study, 61.2% were female and 28.2% were 65 years or older. Four thousand one hundred eighty-seven participants (87.7%) had no significant cataract and no previous cataract surgery; 109 (2.3%) had unilateral visually significant cataract (29 of these had surgery in the other eye); 26 (0.5%) had bilateral visually significant cataract; and 244 (5.1%. had undergone bilateral cataract surgery. There were 90 participants (1.9%) with eyes that could not be graded for cataract or cataract surgery status (table 1). The primary reason for not being able to grade eyes was contraindication or refusal to use dilating drops. In the cohort, 52.0% of those with the severest grade of nuclear cataract, 29.3% of those with cortical cataract grade 8 or higher, and 24.2% of those with PSC had best-corrected acuity worse than 20/40 in the cataractous eye.

Age-specific prevalence of visually significant cataract appeared to be slightly higher in women than in men; however, the age-adjusted odds of having cataract were not different between men and women (odds ratio [OR], 1.32; P = .16) (Table 2). prevalence of visually significant cataract increased with age, as did prevalence of bilateral cataract surgery. The age-adjusted prevalence of unilateral or bilateral cataract surgery was not different between men and women (OR, 1.03; P = .83) (table 3).

A total of 391 participants (8.2%) had undergone cataract surgery in at least 1 eye, and 106 (2.2%) had significant cataract and no previous cataract surgery. There were 29 participants (7.4%) with visually significant cataract who had undergone unilateral cataract surgery; this group was included with those having a history of surgery since we were interested in factors associated with having obtained surgery. On a univariate level, and adjusting for age, those who previously obtained cataract surgery tended to have higher education, medical insurance, and spoke more English; they also had a regular medical care facility and had visited a medical doctor or health care professional recently (table 4).

Comparing those who obtained cataract surgery with those having visually significant cataract (ie, those needing surgery), having medical insurance (OR, 2.88; P<.001) and speaking English (OR, 1.80; p = .04) were significantly associated with having obtained cataract surgery, adjusting for demographic variables and other potential risk factors (table 5). Demographic variables, such as age, sex, income, and city of residence, were not associated with those who obtained cataract surgery when compared with those who required surgery. Substituting the variables of regular care facility or recent medical visit for the variable of having medical insurance resulted in a weaker relationship of these variables with historical cataract surgery. In expanded multivariate models, age and sex interactions with speaking English and having medical insurance were not significantly associated with obtaining surgery.

among the 135 persons with visually significant cataract, 127 (94%) had cataract as either the primary or secondary cause of visual impairment. Other causes of visual impairment included glaucoma, diabetic retinopathy, macular pathologic features, and age-related macular degeneration. Among the group with visually significant cataract, 56 (41%) had initial vision in the better eye of 20/40 or better, thus possibly limiting their awareness of disability and/or desire for cataract surgery.

Among the 391 with previous surgery, 16 had aphakia in at least 1 eye; of these, 1 participant (6.2%) had an abnormal outcome. In the 377 participants with at least 1 pseudophakic eye (2 participants had both aphakia and pseudophakia), 11 (2.9%) had abnormal outcomes or dislocated lenses and 5 (1.3%) had posterior capsular opacity without capsulotomy; 118 (31.3%) had capsulotomy. Best-corrected acuity in the better (operated on) eye appeared to be better in those with pseudophakia; 14 participants with pseudophakia (3.7%) had best-corrected vision worse than 20/200, compared with 6 participants with aphakia (37.5%). Acuity worse than 20/200 in participants with pseudophakia was due to glaucoma in 5 persons, age-related macular degeneration in 2 persons, trauma in 2 persons, and other causes in 5 persons. In most cases, poor acuity in the eyes operated on appeared to have been due to other factors that also influence acuity.

We compared the amount of significant cataract and bilateral cataract surgery between Proyecto VER participants and white and African American participants in the SEE Study. Comparisons revealed higher age-specific rates of significant cataract and cataract surgery among US Hispanic individuals than in African American and white individuals (Table 6). In the SEE Study sample, 30.3% of those with the severest grade of nuclear cataract, 27.3% of those with cortical cataract grade 8 and higher, and 26.7. of those with PSC had best-corrected acuity worse than 20/40; in the US Hispanic sample aged 65 to 84 years, 44.3% of those with severe nuclear cataract, 17.3. of those with severe cortical cataract, and 28.2% of those with PSC had best-corrected acuity worse than 20/40. After adjusting for age, sex, and diabetes mellitus status, US Hispanic individuals were more likely to have significant cataract (OR, 3.87; P<.001) and bilateral cataract surgery (OR, 1.59; P< .001) compared with white individuals and significantly more than African American individuals in the SEE Study (OR for significant cataract, 4.71; P<.001; OR for bilateral cataract surgery, 4.42; p<.001).

This population-based study of US Hispanic individuals of Mexican descent, 40 years and older, found high prevalence of both visually significant cataract and cataract surgery. Age-specific prevalence rates of visually significant cataract and cataract surgery were higher in our Hispanic population than prevalence rates in a white and African American population. Rates of cataract surgery were also higher in our Hispanic population compared with estimated rates combining a number of population-based studies carried out in the United States.¹⁹ Our data suggest that, even after adjusting for high rates of diabetes mellitus, US Hispanic individuals are at greater risk of having a visually impairing cataract than either African American or white individuals. Cataract is the leading cause of visual impairment in this population and is associated with lower levels of self-reported quality of life²⁰; however, a significant percentage of those who likely need cataract removal have never obtained surgery in this population.

We identified 2 important predictors of having obtained cataract surgery in this population. The first is access to medical care. those with a regular service of care or who had medical insurance. Almost 30% of those who likely needed cataract surgery had no medical insurance, not even Medicare or Medicaid. With 86% having an average family income less than $20 000, expenditures for surgery require a significant outlay of family funds. The second predictor was use of English. Those who spoke English were almost twice as likely to have surgery. Speaking the language of the health care culture has been predictive of eye care use⁶ and health care use by Hispanic individuals in other studies,²¹ and the Melbourne Visual Impairment Project found that people speaking languages other than English were less likely to access eye care in general.⁶

The prevalence of visually significant cataract appeared higher in women, while the prevalence of cataract surgery appeared to be approximately the same between men and women, as has been noted in a previous publication.¹ The age-adjusted OR for the probability of having obtained cataract surgery was 0.79 (P = .30) for women, indicating that among those needing surgery, women tended to be less likely than men to obtain surgery, but this difference was not significant. The findings of no association of sex or income with obtaining cataract surgery is in agreement with previous studies.^5,22

There are limitations to our study, primarily owing to the cross-sectional nature of the data. The cataract surgery group could have had cataract surgery at any time in the past, and we do not have data on characteristics at the time of surgery for comparison. Thus, for example, patients who underwent cataract surgery were likely to be younger at the time of surgery and perhaps more likely to have a higher income level. However, the cross-sectional nature of the study would not have affected the findings regarding sex, language, or education.

We chose worse than 20/40 visual acuity as a level where functional disability was found in this study population.²³ However, since cataract surgery is elective, it may be that more severe impairment in the better eye is required before persons with cataract in this community seek eye care services. If so, we are capturing those who are not yet disabled by their current level of acuity impairment and so are not seeking surgery, as well as those who might prefer to seek services but won’t. We did not ask participants specifically about their wish to have cataract surgery, but vision worse than 20/40 was associated with self-report of functional disability.²⁰

In the SEE Study, cataract grading was accomplished using photographs, where graders were masked to acuity status.² Clinical grading was done in Proyecto VER by 1 ophthalmologist trained on the Wilmer grading system, who was not masked to acuity status. While comparability between clinical and photographic grading has been reported,¹⁴ there could still be important differences. We sought to minimize differences by reporting only grades of cataract associated with worse than 20/40 vision. However, we cannot rule out observer bias as an explanation for some of the cataract excess. The fact that cataract surgery rates are much higher in the Hispanic population argues in favor of higher rates of visually significant cataract in this population.

In summary, visually significant cataract appears to be high among US Hispanic individuals of Mexican descent, as evidenced both by rate of cataract and rate of surgery. Language and financial barriers in this population impede access to surgery. Further work to remove these barriers and provide sight restoration is warranted among Hispanic individuals living in the United States.

Correspondence: Sheila K. West, PhD, Wilmer Eye Institute, Room 129, Johns Hopkins Hospital, 600 N Wolfe St, Baltimore, MD 21287 (shwest@jhmi.edu).

Submitted for Publication: October 10, 2003; final revision received September 27, 2004; accepted November 17, 2004.

Financial Disclosure: None.

Funding/Support: This project was supported by grant u10-EY11283 from the National Eye Institute, Bethesda, Md, and a Research to Prevent Blindness (New York, NY) Challenge grant (Dr Snyder and the Department of Ophthalmology at the University of Arizona, Tucson).

Additional Information: Dr West is a Research to Prevent Blindness Senior Scientific Investigator. Ms Broman had full access to all the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis.