Key Points
Questions
What is the prevalence of uncorrected refractive error and what factors are associated with these errors?
Findings
In this cross-sectional study of 707 participants 78 years and older in France, prevalence of uncorrected refractive error was 38.8%, appearing similar among participants with or without eye disease. Prevalence of uncorrected refractive error was nearly 50% among participants who were unable to attend an outpatient clinic.
Meaning
Although easily correctable, these results suggest the prevalence of uncorrected refractive error is high in this older population and that specific groups, including those with and without eye disease or unable to attend an outpatient clinic, could be targeted for preventive actions.
This cross-sectional study estimates the prevalence of uncorrected refractive error in older adults, particularly in those with age-related eye disease and who are unable to attend an outpatient clinic, and identifies the factors associated with uncorrected refractive error.
Abstract
Importance
Uncorrected refractive error (URE) is a common cause of visual impairment, but its prevalence in groups of older adults who could be pragmatic targets for improving optical correction remains unknown.
Objectives
To estimate the prevalence of URE in older adults, particularly in those with age-related eye disease and those who are unable to attend an outpatient clinic, and to identify the factors associated with URE.
Design, Setting, and Participants
This population-based cross-sectional analysis included 707 adults 78 years or older from the Alienor Study in Bordeaux, France. Data were collected from February 12, 2011, through December 21, 2012, and analyzed from November 1, 2017, through July 7, 2018.
Main Outcomes and Measures
Uncorrected refractive error was defined as the presenting distance visual acuity in the better-seeing eye improved by at least 5 letters on the Early Treatment Diabetic Retinopathy Study chart (≥1 line on the logMAR chart) using the best-achieved optical correction. Multivariate logistic regressions were used to determine the factors associated with URE.
Results
The study population of 707 adults 78 years or older (64.8% women; mean [SD] age, 84.3 [4.4] years) had a prevalence of URE of 38.8% (95% CI, 35.2%-42.5%). Prevalence was high for participants with eye disease (range, 35.0% [95% CI, 28.4%-42.0%] to 44.1% [95% CI, 27.2%-62.1%], depending on the disease) and those without eye disease (30.1%; 95% CI, 24.0%-36.7%). Prevalence was higher in participants who were examined at home (because they could not come to the clinic) than in those examined at the clinic (49.4% [95% CI, 42.8%-55.9%] vs 33.5% [95% CI, 29.2%-37.9%]; P < .001). Having an eye examination performed at home (odds ratio [OR], 1.64; 95% CI, 1.13-2.37), living alone (OR, 0.65; 95% CI, 0.47-0.90), and having the perceptions that the ophthalmologist consultation fees are too expensive (OR, 1.94; 95% CI, 1.12-3.36) and that declining visual acuity is normal with aging (OR, 1.47; 95% CI, 1.04-2.08) were all associated with URE.
Conclusions and Relevance
These study results show that the prevalence of URE was high in this population and suggest that preventive strategies aimed at enhancing optical correction could be directed to all older adults and to specific groups by implementing at-home eye examinations for those who have difficulties attending an outpatient clinic and by focusing on those with eye disease who probably already have a regular ophthalmologic follow-up. More studies are needed to evaluate prevalence of URE in different populations and countries with various eye care systems.
Introduction
Visual impairment (VI) is common in older adults. In 2015, 217 million people were estimated to have VI worldwide, with 38.4% of them 70 years or older.1 Visual impairment reduces the quality of life and increases the risk of falls, depression, and cognitive impairment.2,3,4,5,6 Moreover, VI is a leading cause of disability.7,8 Uncorrected refractive error (URE) is the most common cause of VI worldwide, with approximately 53% of VI resulting from URE.9,10 In industrialized countries, the prevalence ranges from 6% to 72%.9,10,11,12,13,14,15,16,17,18 However, because these proportions depend on the URE definition, study setting, and study population, they are not directly comparable.
Some factors influencing URE have been identified and include sociodemographic and ophthalmologic factors,14,15,16,19 but little is known about the barriers to the use of eye care services. Thus, knowledge of these barriers may provide additional clues to guide health prevention programs aimed at reducing VI. In addition, although efforts have been made to achieve the best treatment for age-related eye diseases, optical correction may be neglected for these patients. Indeed, the prevalence of URE in participants with eye disease ranges from 2.4% to 20.5%.16,20 However, such estimates come mostly from young populations, and studies are mainly conducted in outpatient clinics, so little is known about older adults who are unable to attend clinics. Older adults may experience more difficulties with mobility and having access to eye care and optical correction, resulting in a higher prevalence of URE.
The purpose of this study was to estimate the prevalence of URE in an older French population, particularly in specific groups of participants who could be pragmatic targets for improving optical correction: those with eye disease and those who do not attend an outpatient clinic. The second objective was to identify the factors associated with URE, including the barriers to the use of eye care services.
Methods
Study Population
This report is based on the Alienor Study, a French population-based cohort study on nutritional factors and age-related eye diseases. The complete study methods were published previously.21 Participants in the Alienor Study were recruited from the Three-City (3C) Study, an ongoing population-based study on vascular risk factors and dementia.21 The Alienor Study consists of eye examinations offered to all participants of the 3C Study in Bordeaux from the initial data collection wave from October 2, 2006, through May 23, 2008. Initially, eye examinations were performed only at the Department of Ophthalmology of the Bordeaux University Hospital (hereinafter referred to as the ophthalmology clinic). From the 4-year follow-up (February 21, 2011, through December 21, 2012), eye examinations at home (at the participant’s place of residence) were proposed to all the participants who could not come to the clinic. At this follow-up, a questionnaire about the barriers to the use of eye care services was also administered. Among the 959 participants from the 3C Study who were visited at this follow-up, 709 received an eye examination (at home or at the ophthalmology clinic); among them, 707 with data on presenting and best-corrected distance visual acuities (VAs) constituted the study sample. Participants without eye examinations appeared to be older and more often women, to have a lower socioeconomic status, and to have more limitations and dementia (eTable 1 in the Supplement). Participants gave written informed consent for the participation in the study. The design of the Alienor Study was approved by the Ethical Committee of Bordeaux (Comité de Protection des Personnes Sud-Ouest et Outre-Mer III).
Eye Examination
The examination included measures of refraction, presenting and best-corrected distance monocular VAs, and intraocular pressure and color retinal photographs. In addition, for the participants seen at the clinic, grading of lens opacities and spectral domain optical coherence tomography examinations were performed. At the clinic, VA was evaluated using the Early Treatment Diabetic Retinopathy Study (ETDRS) charts at 4 m, scored as the total number of letters read correctly. Charts 1 and 2 were used for testing the right and left eyes, respectively. Objective noncycloplegic refraction was measured with an autorefractometer and subjective refraction with trial lenses and frames. At home, VA was evaluated at a 3-m distance with the electronic VA system tester laptop, allowing the ETDRS scores to be measured. A screen calibration and a control of the screen light intensity were performed each week. All examinations were performed in a dark place. Objective refraction was measured using a portable autorefractometer, and subjective refraction was measured with trial lenses and frames.
VI and UREs
Visual impairment refers to the presenting distance VA in the better-seeing eye. We created categories of at least 5 letters (corresponding to 1 line of the ETDRS chart), as follows3: greater than 80 letters (Snellen equivalent, >20/25) as the reference group, 76 to 80 letters (Snellen equivalent, >20/32 to 20/25), 71 to 75 letters (Snellen equivalent, >20/40 to 20/32), 61 to 70 letters (Snellen equivalent, >20/63 to 20/40), and 60 letters or fewer (Snellen equivalent, ≤20/63). Best-corrected VA was based on results of subjective refraction. Uncorrected refractive error was defined as the presenting distance VA in the better-seeing eye that was improved by 5 letters or more (≥1 line on the ETDRS chart) when using the best-achieved optical correction. We also explored other definitions of URE. Gains in VA were defined as the difference between the best-corrected and presenting VA, expressed as the number of ETDRS letters read correctly.
Diagnosis of Eye Diseases
As previously described in detail,22 the diagnosis of age-related macular degeneration was performed according to the international classification and to a modification of the grading scheme used in the Multi-Ethnic Study of Atherosclerosis.23 Glaucoma was classified according to the classification proposed by Foster et al.24 A classification of cataract was based on the Lens Opacities Classification System III evaluation of lens opacities at the slitlamp25 after pupil dilation in participants with no history of cataract surgery. Because the grading of lens opacities and spectral domain optical coherence tomography examinations were performed only for participants examined at the clinic, only these participants were included in the analyses of URE according to eye disease.
Other Factors
The following sociodemographic and lifestyle factors were considered: age, sex, educational level, monthly income, living alone, living in a nursing home, and smoking. Depressive symptoms were defined as a score of at least 17 for men and at least 23 for women on the Center for Epidemiologic Studies–Depression Scale (range, 0-60, with higher scores indicating depressive symptoms).26,27 Medical variables included the self-reported history of cardiovascular disease, diabetes, and hypertension. Dementia was actively screened using an extensive cognitive and functional evaluation, and the diagnosis was based on the Diagnostic and Statistical Manual of Mental Disorders (Fourth Edition) criteria.21 Basic activities of daily living (ADL) were assessed with the scale of Lawton and Brody28; instrumental ADL (IADL), with the scale of Katz et al.29 A participant was considered limited if he or she could not perform at least 1 activity without human help. In addition, participants were asked if they were still driving. The delay since the last eye examination and barriers to the use of eye care services were assessed. The perceptions of the participants regarding barriers included the perceptions that the ophthalmologist consultation fees were too expensive, that getting an ophthalmologist appointment was difficult, that moving about was difficult, that declining vision is normal with aging, and that eyeglass or lens fees were too expensive.
Statistical Analysis
Data were analyzed from November 1, 2017, through July 7, 2018. The prevalence of URE and the median and interquartile range of VA gains were estimated globally and according to eye disease and place of eye examination (home or the ophthalmology clinic). Eye diseases were classified into the following 3 categories: (1) retinal disease or glaucoma; (2) only cataract (excluding participants with previous cataract extraction); and (3) no retinal disease, glaucoma, or cataract. A cross-tabulation of presenting VA with best-corrected VA was computed overall and according to the presence of eye disease and the place of examination. Univariate and multivariate logistic regression analyses were used to identify the factors associated with URE. The factors studied were age (adjusted for in all models), sex, income, educational level, living alone, living in a nursing home, smoking, still driving, IADL and ADL limitations, dementia, diabetes, hypertension, cardiovascular diseases, depressive symptoms, place of examination, delay since the last eye examination, and barriers to the use of eye care services. All factors associated with URE (at P ≤ .20) in the univariate analysis were included in an initial multivariate model. The final multivariate model was obtained using a manual backward stepwise selection strategy. Values of P < .05 were considered significant. Odds ratios (ORs) with the 95% CIs were reported. Analyses were performed using the SAS software (version 9.3; SAS Institute, Inc).
Results
Study Sample
Among the 707 study participants, the mean (SD) age was 84.3 (4.4) years; 458 (64.8%) were women and 249 (35.2%) were men; and 302 (42.7%) had a higher level of education (Table 1). Overall, 323 of 706 participants (45.8%) were still driving, 261 of 699 (37.3%) had IADL limitations, 97 of 694 (14.0%) had diabetes, and 87 of 707 (12.3%) had dementia. A total of 280 participants (39.6%) had a presenting distance VA of greater than 20/25. Among the 450 participants examined at the clinic without missing data for the diagnosis of eye disease, 203 (45.1%) had a retinal disease or glaucoma, 34 (7.6%) had a cataract, and 213 (47.3%) had no retinal disease, glaucoma, or cataract.
Table 1. Sociodemographic, Medical, and Ophthalmologic Characteristics of the Study Samplea.
| Characteristic | Data (n = 707) |
|---|---|
| Sociodemographic | |
| Age, mean (SD), y | 84.3 (4.4) |
| Female, No. (%) | 458 (64.8) |
| Educational level, No. (%) | |
| Elementary school without diploma | 67 (9.5) |
| Short secondary school | 338 (47.8) |
| Higher level | 302 (42.7) |
| Monthly income, No. (%), €b,c | |
| <1500 | 182 (26.8) |
| 1500-2300 | 178 (26.2) |
| >2300 | 251 (37.0) |
| Refusal to answer | 68 (10.0) |
| Medical | |
| Living alone, No. (%) | 308 (43.6) |
| Living in a nursing home, No. (%) | 53 (7.5) |
| Place of eye examination, No. (%) | |
| Ophthalmology clinic | 472 (66.8) |
| Home | 235 (33.2) |
| Still driving, No. (%)d | 323 (45.8) |
| IADL limitations, No. (%)e | 261 (37.3) |
| ADL limitations, No. (%)f | 72 (10.2) |
| Diabetes, No. (%)g | 97 (14.0) |
| Hypertension, No. (%)h | 352 (51.4) |
| Cardiovascular diseases, No. (%)i | 251 (36.6) |
| Smoking, No. (%), pack-yearsj | 220 (31.4) |
| None | 480 (68.6) |
| <20 | 113 (16.1) |
| ≥20 | 107 (15.3) |
| Depressive symptoms, No. (%)k | 95 (14.6) |
| Dementia, No. (%) | 87 (12.3) |
| Ophthalmologic | |
| Presenting distance VA, No. (%)l | |
| >20/25 | 280 (39.6) |
| >20/32 to 20/25 | 174 (24.6) |
| >20/40 to 20/32 | 101 (14.3) |
| >20/63 to 20/40 | 95 (13.4) |
| ≤20/63 | 57 (8.1) |
| Use of glasses or contact lenses for distance vision, No. (%)m | 540 (76.5) |
| Time since last examination, median (IQR), yn | 1.0 (0-2) |
| Barriers to consult an ophthalmologist, No. (%) | |
| Consultation fee | 69 (9.8) |
| Moving difficulties | 117 (16.5) |
| Perception that visual decline is normal with aging | 390 (55.2) |
| Barriers to change eyeglasses or lenses, No. (%) | |
| Consultation fee | 108 (15.3) |
| Moving difficulties | 103 (14.6) |
| Perception that visual decline is normal with aging | 389 (55.0) |
Abbreviations: ADL, activities of daily living; IADL, instrumental activities of daily living; IQR, interquartile range; VA, visual acuity.
Participants are from the Alienor Study.21
Data were missing for 28 participants.
To convert € to US dollars, multiply by 1.16.
Data were missing for 1 participant.
Data were missing for 8 participants.
Data were missing for 2 participants.
Data were missing for 13 participants.
Data were missing for 22 participants.
Data were missing for 21 participants.
Data were missing for 7 participants.
Data were missing for 55 participants.
The correspondence of visual impairment levels between Early Treatment Diabetic Retinopathy Study and Snellen levels was better than 20/25 for more than 80 letters; better than 20/32 to 20/25 for 76 to 80 letters; better than 20/40 to 20/32 for 71 to 75 letters; better than 20/63 to 20/40 for 61 to 70 letters; and 20/63 or worse for 60 letters or fewer.
Data were missing for 1 participant.
Data were missing for 14 participants.
URE and VA Gains
Overall, 274 patients had URE (38.8%; 95% CI, 35.2%-42.5%), with a median VA gain of 3 ETDRS letters (interquartile range, 1-6) (Table 2). After adjusting for age, the proportion of URE was not significantly different according to the presence of eye disease (P = .15), but it tended to be higher in participants with cataract (15 of 34 [44.1%; 95% CI, 27.2%-62.1%]) or retinal disease or glaucoma (71 of 203 [35.0%; 95% CI, 28.4%-42.0%]) than in those with no eye disease (64 of 213 [30.0%; 95% CI, 24.0%-36.7%]). The proportion of URE was significantly higher in participants examined at home than in those examined at the ophthalmology clinic (116 of 235 [49.4%; 95% CI, 42.8%-55.9%] vs 158 of 472 [33.5%; 95% CI,29.2%-37.9%]; P < .001).
Table 2. Prevalence of URE and VA Gainsa.
| Patient Characteristic | URE With Improvement of VA ≥1 ETDRS Line, No. (%) [95% CI]b | P Valuec | VA Gain, Median (IQR)d |
|---|---|---|---|
| All (n = 707) | 274 (38.8) [35.2-42.5] | NA | 3 (1-6) |
| Presence of age-related eye diseasee | |||
| No cataract, glaucoma or retinal disease (n = 213) | 64 (30.0) [24.0-36.7] | .15 | 2 (0-5) |
| Retinal disease or glaucoma (n = 203) | 71 (35.0) [28.4-42.0] | 3 (1-6) | |
| Cataract only (n = 34) | 15 (44.1) [27.2-62.1] | 4 (1-7) | |
| Place of eye examination | |||
| Ophthalmology clinic (n = 472) | 158 (33.5) [29.2-37.9] | <.001 | 2 (1-6) |
| Home (n = 235) | 116 (49.4) [42.8-55.9] | 4 (2-8) |
Abbreviations: ETDRS, Early Treatment Diabetic Retinopathy Study; IQR, interquartile range; URE, uncorrected refractive error; VA, visual acuity.
Participants are from the Alienor Study.21
Indicates improvement of VA with best-achieved optical correction.
Adjustment for age except for variable age.
Expressed in number of ETDRS letters.
Indicates among participants examined at the ophthalmology clinic.
Among 134 participants with a presenting distance VA of worse than 20/40 in the better-seeing eye, 72 (53.7%) could achieve a VA of 20/40 or better with the best-achieved optical correction. Prevalence of URE using other definitions are given in eTable 2 in the Supplement. In the total sample, an improvement of VA with a best-achieved optical correction was observed in each presenting VA category (Figure), including the lowest range (≤20/63). This VA improvement occurred in 111 of the 174 participants (63.8%) with a presenting VA of greater than 20/32 to 20/25 and 28 of 57 (49.1%) with a presenting VA of 20/63 or worse (Table 3). Regardless of the category of presenting VA and the group of participants (with vs without eye disease and examined at home vs in the ophthalmology clinic), an improvement of VA of at least 44% was obtained.
Figure. Best-Corrected Distance Visual Acuity (VA) by Presenting Distance VA in the Better-Seeing Eye.
Data are obtained from the Alienor Study.21 Among participants with presenting distance VA of 20/63 or worse, 7.0% improved to better than 20/25 with best-achieved optical correction; 8.8%, to better than 20/32 to 20/25; 5.3%, to better than 20/40 to 20/32; and 28.1%, to better than 20/63 to 20/40. The remaining 50.9% did not improve. The percentages above the bracket correspond to the global proportions of participants who improved their VA with best-achieved optical correction, for each category of presenting VA.
Table 3. Best-Corrected Distance VA by Presenting Distance VA in the Better-Seeing Eyea.
| Presenting Distance VA by Participant Groupb | Best-Corrected Distance VA, No. (%) | Improvement, %c | Total, No. (%) | ||||
|---|---|---|---|---|---|---|---|
| >20/25 | >20/32 to 20/25 | >20/40 to 20/32 | >20/63 to 20/40 | ≤20/63 | |||
| All (n = 707) | |||||||
| >20/25 | 280 (100.0) | NA | NA | NA | NA | NA | 280 (100) |
| >20/32 to 20/25 | 111 (63.8) | 63 (36.2) | NA | NA | NA | 63.8 | 174 (100) |
| >20/40 to 20/32 | 34 (33.7) | 38 (37.6) | 29 (28.7) | NA | NA | 71.3 | 101 (100) |
| >20/63 to 20/40 | 14 (14.7) | 22 (23.2) | 27 (28.4) | 32 (33.7) | NA | 66.3 | 95 (100) |
| ≤20/63 | 4 (7.0) | 5 (8.8) | 3 (5.3) | 16 (28.1) | 29 (50.9) | 49.1 | 57 (100) |
| Without cataract, retinal disease, or glaucoma (n = 213) | |||||||
| >20/25 | 111 (100) | NA | NA | NA | NA | NA | 111 (100) |
| >20/32 to 20/25 | 44 (66.7) | 22 (33.3) | NA | NA | NA | 66.7 | 66 (100) |
| >20/40 to 20/32 | 9 (39.1) | 9 (39.1) | 5 (21.7) | NA | NA | 78.3 | 23 (100) |
| >20/63 to 20/40 | 2 (16.7) | 4 (33.3) | 2 (16.7) | 4 (33.3) | NA | 66.7 | 12 (100) |
| ≤20/63 | 0 | 1 (100) | 0 | 0 | 0 | 100 | 1 (100) |
| With retinal disease or glaucoma (n = 203) | |||||||
| >20/25 | 81 (100) | NA | NA | NA | NA | NA | 81 (100) |
| >20/32 to 20/25 | 38 (61.3) | 24 (38.7) | NA | NA | NA | 61.3 | 62 (100) |
| >20/40 to 20/32 | 7 (36.8) | 8 (42.1) | 4 (21.1) | NA | NA | 78.9 | 19 (100) |
| >20/63 to 20/40 | 3 (12.5) | 4 (16.7) | 5 (20.8) | 12 (50.0) | NA | 50.0 | 24 (100) |
| ≤20/63 | 1 (5.9) | 2 (11.8) | 1 (5.9) | 5 (29.4) | 8 (47.1) | 52.9 | 17 (100) |
| With cataract (n = 34) | |||||||
| >20/25 | 12 (100) | NA | NA | NA | NA | NA | 12 (100) |
| >20/32 to 20/25 | 9 (75.0) | 3 (25.0) | NA | NA | NA | 75.0 | 12 (100) |
| >20/40 to 20/32 | 0 | 2 (100) | 0 | NA | NA | 100 | 2 (100) |
| >20/63 to 20/40 | 1 (14.3) | 2 (28.6) | 2 (28.6) | 2 (28.6) | NA | 71.4 | 7 (100) |
| ≤20/63 | 0 | 0 | 1 (100) | 0 | 0 | 100 | 1 (100) |
| Examined at home (n = 235) | |||||||
| >20/25 | 69 (100) | NA | NA | NA | NA | NA | 69 (100) |
| >20/32 to 20/25 | 17 (58.6) | 12 (41.4) | NA | NA | NA | 58.6 | 29 (100) |
| >20/40 to 20/32 | 18 (33.3) | 18 (33.3) | 18 (33.3) | NA | NA | 66.7 | 54 (100) |
| >20/63 to 20/40 | 7 (14.9) | 10 (21.3) | 17 (36.2) | 13 (27.7) | NA | 72.3 | 47 (100) |
| ≤20/63 | 3 (8.3) | 2 (5.6) | 1 (2.8) | 10 (27.8) | 20 (55.6) | 44.4 | 36 (100) |
| Examined at ophthalmology clinic (n = 472) | |||||||
| >20/25 | 211 (100) | NA | NA | NA | NA | NA | 211 (100) |
| >20/32 to 20/25 | 94 (64.8) | 51 (35.2) | NA | NA | NA | 64.8 | 145 (100) |
| >20/40 to 20/32 | 16 (34.0) | 20 (42.6) | 11 (23.4) | NA | NA | 76.6 | 47 (100) |
| >20/63 to 20/40 | 7 (14.6) | 12 (25.0) | 10 (20.8) | 19 (39.6) | NA | 60.4 | 48 (100) |
| ≤20/63 | 1 (4.8) | 3 (14.3) | 2 (9.5) | 6 (28.6) | 9 (42.9) | 57.1 | 21 (100) |
Abbreviations: NA, not applicable; VA, visual acuity.
Participants are from the Alienor Study.21
The correspondence of visual impairment levels between Early Treatment Diabetic Retinopathy Study and Snellen levels was better than 20/25 for more than 80 letters; better than 20/32 to 20/25 for 76 to 80 letters; better than 20/40 to 20/32 for 71 to 75 letters; better than 20/63 to 20/40 for 61 to 70 letters; and 20/63 or worse for 60 letters or fewer.
Indicates the proportion of participants who improved their VA with best-achieved optical correction for each category of presenting VA.
Factors Associated With URE
The factors associated with URE in univariate analyses are displayed in Table 4 (initial multivariate model). In the final multivariate model, only the following 4 factors were still significantly associated with having URE: eye examination performed at home (OR, 1.64; 95% CI, 1.13-2.37), living alone (OR, 0.65; 95% CI, 0.47-0.90), the perception that the ophthalmologist consultation fees were too expensive (OR, 1.94; 95% CI, 1.12-3.36), and the perception that visual decline with aging is normal (OR, 1.47; 95% CI, 1.04-2.08).
Table 4. Factors Associated With UREa.
| Variables | Initial Multivariate Model (n = 672)b | Final Multivariate Model (n = 672)c | ||
|---|---|---|---|---|
| OR (95% CI) | P Value | OR (95% CI) | P Value | |
| Sociodemographic Factors | ||||
| Aged | 0.98 (0.94-1.02) | .34 | 0.99 (0.95-1.02) | .44 |
| Educational level | ||||
| Elementary school without diploma | 1 [Reference] | .89 | NA | NA |
| Short secondary school | 0.98 (0.55-1.77) | .96 | NA | NA |
| Higher level | 0.91 (0.50-1.66) | .75 | NA | NA |
| Living alone | 0.65 (0.46-0.92) | .02 | 0.65 (0.47-0.90) | .01 |
| Living in a nursing home | 1.24 (0.54-2.86) | .61 | NA | NA |
| Medical Factors | ||||
| Still driving | 0.75 (0.50-1.13) | .17 | NA | NA |
| ADL limitations | 0.8 (0.39-1.63) | .54 | NA | NA |
| IADL limitations | 0.95 (0.59-1.53) | .84 | NA | NA |
| Diabetes | 1.53 (0.96-2.44) | .07 | NA | NA |
| Dementia | 1.15 (0.59-2.22) | .69 | NA | NA |
| Ophthalmologic Factors | ||||
| Examined at home | 1.62 (1.08-2.41) | .02 | 1.64 (1.13-2.37) | .009 |
| Delay since last eye examination | 1.03 (0.97-1.10) | .35 | NA | NA |
| Barriers to consult an ophthalmologist | ||||
| Consultation fee | 2.09 (1.08-4.03) | .03 | 1.94 (1.12-3.36) | .02 |
| Moving difficulties | 1.21 (0.44-3.29) | .71 | NA | NA |
| Perception that visual decline is normal with aging | 1.62 (0.89-2.94) | .12 | 1.47 (1.04-2.08) | .03 |
| Barriers to change eyeglasses or lenses | ||||
| Consultation fee | 0.84 (0.50-1.41) | .50 | NA | NA |
| Moving difficulties | 0.60 (0.20-1.76) | .35 | NA | NA |
| Perception that visual decline is normal with aging | 0.87 (0.48-1.59) | .66 | NA | NA |
Abbreviations: ADL, activities of daily living; IADL, instrumental ADL; NA, not applicable; OR, odds ratio; URE, uncorrected refractive error.
Participants are from the Alienor Study.21
Multivariate model including all the variables significant at P < .20 in univariate analysis adjusted for age.
Multivariate model obtained using a manual backward stepwise selection strategy after exclusion of variables with P < .05.
Age is forced in all the models.
Discussion
In this elderly population, we found that nearly 40% of the participants had URE. This proportion was high in participants with eye disease (range, 35.0%-44.1%) and in those without (30.1%). The proportion was also high in those participants examined at home, nearly half of whom had URE. Regardless of the presence of eye disease or the place of examination, a large improvement in VA of at least 44% was obtained with a best-achieved optical correction, even in participants in the lowest categories of presenting VA. Being examined at home, not living alone, and having the perceptions that the ophthalmologist consultation fees were too expensive and that visual decline with aging is normal were associated with a higher prevalence of URE.
Most previous studies evaluated URE not in the general population as we did but in a population with at least a mild level of visual deficiency. Moreover, different definitions have been used for URE, which makes comparisons difficult. Within participants with a VA of less than 20/20, URE was estimated at 45% in the Blue Mountains Eye Study and at 54% in the Baltimore Eye Study30,31; this proportion was 57% in the Melbourne Visual Impairment Project for participants with a VA of worse than 20/20 minus 2 letters.20 Our findings are in accordance with these previous results, with 45.2% of participants with a presenting VA of worse than 20/20 and 52.4% of participants with a presenting VA of worse than 20/20 minus 2 letters having URE.
In our study, we observed high proportions of URE, even in participants with eye disease. This high proportion was observed regardless of the VI severity. Because people with eye disease are usually under ophthalmologic care, we expected to find a somewhat lower prevalence of URE. This result may suggest that although much attention has been given to treating eye disease (which is usually the target of ophthalmologic care), optical correction may have received less attention. In addition, some patients with end-stage eye disease and low VA might no longer visit their ophthalmologist, thinking that nothing can improve their vision anymore. In previous studies,16,20 the proportions of URE in participants with eye disease were lower than ours, ranging from 2.4% to 20.5% in the Melbourne Visual Impairment Project study (depending on the eye disease considered) and from 2.7% to 20.5% in the Blue Mountain Eye Study. However, the populations studied were younger, with a mean age of 66.2 years in the Blue Mountain Eye Study and 53.5% younger than 70 years in the Melbourne Visual Impairment Project study, whereas the mean age in our study was 84.3 years.
The design of our study allowed us to estimate the proportion of URE according to the place of eye examination. We found that 49.4% of participants who were examined at home had URE, which was significantly higher than the percentage in participants seen at the clinic. Because the participants examined at home were older and more disabled, this high proportion of URE may have been owing to functional limitations. However, ADL and IADL limitations were not associated with URE in multivariate analysis, although a higher proportion of these limitations was found in the univariate analyses. In addition, these participants may have been fatalistic and less concerned about their health, consistent with the perception that visual decline is normal with aging being associated with a higher proportion of URE. In any case, these results suggest that proposing ophthalmologic screening at home might help improve URE in the elderly.
Some factors influencing URE have already been identified, including demographic factors, educational attainment, living conditions,14,16,19,20,30,32,33 financial resources,16,19,33 health insurance,19,32 retiring from driving,16 body mass index,19 eye diseases and visual conditions,14,16,20,33 and time since the last eye examination.16,20,32 We did not find any association for age, sex, educational attainment, time since the last eye examination, and driving. Whereas age was associated with URE in most studies, the lack of age variability in our elderly population probably prevented us from suggesting age as a risk factor for URE. In contrast, living alone was associated with a lower proportion of URE, with older participants able to live alone probably being healthier and having fewer mobility restrictions. Participants who were examined at home had a higher risk of URE. Even if we explore other factors such as dementia, activity limitations, or living in a nursing home, which have been previously associated with high prevalence of VI,34,35,36 none of these were associated with URE in our multivariate model. However, these factors are intercorrelated, which may mitigate their potential individual effect on URE.
For the barriers to the use of eye care services, we found that the perceptions that the ophthalmologist consultation fees were too expensive and that visual decline with aging is normal were associated with a higher prevalence of URE. Concordant results were obtained within focus group interviews conducted in South Wales among 63 participants (mean age, 72 years).37 Reasons that prevented older adults from accessing eye examinations were cost, particularly in relation to purchasing glasses, and acceptance of deteriorating visual loss as a normal aging process. In another focus group conducted in England among 81 participants (mean age, 73 years),38 the reasons identified were concern about getting the tests “wrong,” looking foolish, and the perception that wearing glasses was associated with an old and frail appearance.
Strengths and Limitations
The major strength of our study is that presenting and best-corrected VAs were measured by trained technicians in standardized conditions, preventing biases due to self-reported impairment and underdiagnosis of VI. Moreover, the process allowed the improvement using best-achieved optical correction to be assessed. In addition, eye diseases were actively screened for according to standardized diagnostic criteria, which prevented a bias due to the underdiagnosis of these diseases. Finally, examinations were performed at home when the participant could not or did not want to come to the clinic, thus limiting selection bias.
Our study has potential limitations. First, the design is cross-sectional, so we were unable to verify whether the investigated factors occurred before URE. Second, for technical reasons, the diagnosis of eye disease could be performed only for examinations performed at the clinic. Third, our population was very old, which prevented us from generalizing the results to younger populations. Because previous studies have identified age as a risk factor for URE, this older population is of particular interest and can add substantial knowledge to the previous literature. However, we found no evidence of any differences in URE prevalence between participants aged 73 to 77 years and those 78 years or older at the baseline time of the Alienor Study (including participants aged ≥73 years), and results in the literature already found a high prevalence of URE in populations 40 years or older or 50 years or older,13,14,15 suggesting that these figures are not specific to a very elderly population. Finally, despite the proposal of eye examinations at participants’ homes, some of them declined and may have higher proportions of URE.
Conclusions
Although URE is easily correctable, we found that nearly 40% of our population had URE, regardless of the VI severity. However, because VI has been associated with several negative outcomes in aging, improving URE may be a target for maintaining healthy aging.
Thus, awareness actions may be implemented to inform older adults that VI can be improved by adapted optical correction and that VI is not necessarily a normal part of aging. Preventive actions should be directed to all elderly people and to specific groups by implementing at-home eye examinations for those who have difficulties in attending an outpatient clinic and by focusing on those with eye disease who probably already have a regular ophthalmologic follow-up. More studies are needed to evaluate prevalence of URE according to age groups and in different populations and countries with various eye care systems to define more accurately which populations could beneficiate from prevention.
eTable 1. Characteristics of All the Participants According to the Participation in the Alienor Study (n = 952)
eTable 2. Estimations of Uncorrected Refractive Errors (URE) According to Different Definitions
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Associated Data
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Supplementary Materials
eTable 1. Characteristics of All the Participants According to the Participation in the Alienor Study (n = 952)
eTable 2. Estimations of Uncorrected Refractive Errors (URE) According to Different Definitions