Low Rates of Eye Care Utilization among Visually Impaired Subsidized Senior Housing Residents

Abstract

Objective:

To examine the rate of self-reported vision impairment, eye disease, and eye care utilization among residents of subsidized senior housing (SSH) communities.

Methods:

In this cross-sectional, observational study, residents of 14 SSH communities in Jefferson County, AL, USA self-reported their vision status and eye care utilization as part of vision screening events held in their community.

Results:

237 residents self-reported their vision status, presence of eye disease, and eye care utilization. A third of participants (33.3%) reported difficulty with distance vision while 38% reported difficulty with near vision. Rates of eye disease among this sample were as follows: 40.3% reported having cataracts, 13.6% reported having glaucoma, 4.2% reported having age-related macular degeneration, and 5.5% reported having diabetic retinopathy. The majority of participants (52.8%) had not been to see an eye care provider within the last year. Persons with vision impairment were less likely to report having seen an eye care provider within the last year than those without impairment (p=0.03).

Conclusion:

This study illuminates the low utilization of eye care among socioeconomically disadvantaged older adults residing in SSH, especially among those with vision impairment and eye disease. Vision-related health care is important in maintaining both physical and mental health in older adults.

Older adults experience higher rates of eye diseases and conditions that can cause vision impairment, such as diabetes and hypertension, as compared to younger adults. (American Diabetes Association, 2013; Bhargava, Ikram, & Wong, 2012; Prevent Blindness America, 2008). Impaired vision can be debilitating, leading to impairments in both physical and mental health. Older adults with vision impairment experience decreased ability to perform basic activities, loss of driving ability, and ultimately a loss of independence (Wood et al., 2005). Older adults with vision impairment also report lower self-rated health than those without vision impairment (Damian, Pastor-Barriuso, & Valderrama-Gama, 2008; Hwang, Rudnisky, Bowen, & Johnson, 2015; Wang, Mitchell, & Smith, 2000; Whitson, Malhotra, Chan, Matchar, & Ostbye, 2014). Impaired near vision has been associated with incident cognitive impairment, a risk factor for transitioning to a nursing home from a more independent living situation (Lin et al., 2004; Reyes-Ortiz et al., 2005; Wang, Mitchell, Smith, Cumming, & Leeder, 2001). Additionally, vision impairment had been found to be associated with anxiety, depression, and dementia among older adults (Hamedani, VanderBeek, & Willis, 2019). However, the majority of vision impairment in older adults is caused by reversible or correctable conditions (Friedman et al., 2005; Tielsch, Javitt, Coleman, Katz, & Sommer, 1995). Therefore seeking care for vision related issues is a necessary step to maintaining one’s physical and mental health as well as independence later in life.

Older adults live in a variety of settings such as in the community, assisted living facilities, or nursing homes. Much of the previous research concerning the prevalence of vision impairment and eye diseases in older adults has focused on either community dwelling older adults or nursing home residents. These studies have found that residents of nursing homes have vision impairment rates that are 3 to 15 times higher than their community dwelling counterparts (Crews & Campbell, 2004; Mitchell, Hayes, & Wang, 1997; Owsley et al., 2007; Tay et al., 2006; Tielsch et al., 1995). Less attention has been paid to socioeconomically disadvantaged older adults residing in federally subsidized senior housing (SSH) communities. Through Section 202 of the United States Housing Act of 1959 and amendments, the Department of Housing and Urban Development provides funds to subsidize rent within apartment facilities to provide housing for senior adults who are economically disadvantaged. To qualify, the resident must be 62 years of age or older, have an annual income less than 50% of the median income within the county of residence, and be without significant disability (Barbara et al., 2008; Perl, 2010). Previous research has shown that eye care utilization rates are lower among socioeconomically disadvantaged adults (Zhang et al., 2012). Additionally, Varadaraj and colleagues (2019) found through 9-years of National Health Interview Survey data that Americans with lower poverty-to-income ratios (PIR) had lower eye care use and more difficulty affording glasses than those with higher PIR. They also found that minorities were less likely to use eye care than whites. It is likely that persons living in these SSH communities where a large percentage of residents are minorities could have poorer utilization of eye health services than other community-dwelling older adults.

Previous research has found that socioeconomically disadvantaged minority older adults are also more likely to experience mental health disorders such as anxiety and depression than non-minorities. Robinson and colleagues (2009) examined mental health among minority older adults living in low-income senior housing and found that 17% of older black residents experienced major depressive disorder and 6% experienced generalized anxiety disorder. It is also important to note that vision impairment presents another risk factor for mental health disorders. Older adults with vision impairment were found to have significantly higher rates of major depressive disorders and anxiety disorders as compared to their normally sighted peers (van der Aa, Comijs, Penninx, van Rens, & van Nispen, 2015). Very little is known about the specific vision difficulties experienced by those living in federally SSH communities. Given that the population of older adults in the U.S. is expected to almost double by 2050, (Ortman, Velkoff, & Hogan, 2014) and a proportion of older adults will reside SSH communities, it is important to understand their vision health needs in order to develop programs to provide preventive care for both their physical and mental health. The aim of the current study is to present a description of self-reported eye disease, vision impairment, and eye care utilization rates among a sample of SSH residents in Jefferson County, Alabama. To our knowledge, this is the first study to present self-reported vision data in this economically disadvantaged subgroup of older adults.

Methods

Federally SSH communities in Jefferson County, Alabama were identified through the Department of Housing and Urban Development. The manager at each community was sent a recruitment letter inviting them to participate in a no cost vision screening event to be held at their housing community. Detailed study procedures and methods regarding the vision screening events have previously been described (Elliott, McGwin, Kline, & Owsley, 2015). Briefly, each housing community received at least 2 follow-up telephone calls to determine whether they were interested in having an event at their facility. After two unreturned follow-up phone calls and voice messages it was concluded that the housing community was uninterested. Of the 19 SSH communities identified, 14 desired participation, one declined participation, and four were unreachable via letter and telephone (74% participation rate).

Two weeks prior to the date of the vision screening, packets were mailed to the housing community’s manager containing letters to be distributed to all of the residents which described the vision screening event including the date, time, and location where it would be held onsite. Flyers containing this same information were also provided to be posted around the community in advance of the screening event. On the day of the screening event, residents were seen on a first come, first served basis although some residents had chosen to make appointments in advance as this option was offered through the letters/flyers they received in advance of the screenings. If all interested residents at a community could not be accommodated in a single day, arrangements were made to return to provide additional screening events. No person was denied vision screenings. This resulted in a convenience sample of residents who chose to attend the screenings. If residents were 60 years of age or older they were invited to complete interviewer-administered questionnaires on basic demographic information (e.g., birth date, marital status), general health, mental status, eye care utilization, the presence of eye conditions, and whether they experience any difficulty in everyday visual tasks. The Vision Module questionnaire of the Behavioral Risk Factor Surveillance System (BRFSS) (Centers for Disease Control and Prevention) was used in collecting this information. Informed consent was obtained from each resident prior to administration of the questionnaires by trained research staff. This study was approved by the Institutional Review Board of the University of Alabama at Birmingham and follows the tenets of the Declaration of Helsinki.

Statistical Analysis

Descriptive statistics (e.g., means, proportions) were used to calculate the rate of overall and age-specific demographic information and self-reported vision difficulties, eye diseases, and eye care utilization. Chi-square analyses were conducted to evaluate if any observed differences noted within the self-reported demographic and vision health responses differed by age or whether vision difficulties were at near or far distances. Two-sided p-values ≤ 0.05 were considered statistically significant and all analyses were performed using Statistical Analysis Software (SAS Institute Inc., Cary, North Carolina).

Results

A total of 237 residents who participated in the vision screening events were eligible to participate in the questionnaire portion of this study. Results of the objective vision screening are described in Elliott et al. (2015). Participation rates of residents in the screening events varied among communities ranging from 9% to nearly 40%. Table 1 presents the demographic and medical characteristics of participants stratified by self-reported vision impairment. Vision impairment was defined as a BRFSS response of a little difficulty, moderate difficulty, extreme difficulty, or unable to do due to eyesight on either the near or far visual task BRFSS question. (Note: for these analyses responses of don’t know were treated as missing). The sample ranged in age from 60 to 99 years old with the majority being in their 60s or 70s. Due to the low number of participants in their 90s (n=19), for analytical purposes they were combined with the 80 year old group to allow for more balanced group sizes. The majority of participants were African American (74.7%), female (74.3%), single (including separated, divorced, and widowed) (97.9%) and lived alone (98.3%). Fifty-eight percent had a high school or higher level of education. Three-quarters of participants self-reported having hypertension and 38.8% reported having diabetes. There were very few demographic differences between those with and without vision impairment. Chi-square tests revealed that self-reported general health status was significantly poorer among those with vision impairment (p=0.023).

Table 1.

Demographic and medical characteristics by self-reported visual impairment

	N	%	Without Impairment %	With Impairment %	p-value
Sex
Male	61	25.74	24.14	28.21	0.4801
Female	176	74.26	75.86	71.79
Age (years)
60–69	78	32.91	42.86	57.14	0.2525
70–79	89	37.55	50.57	49.43
≥ 80	70	29.54	56.52	43.48
Race
Black	177	74.68	75.86	74.36	0.7794
White (Non Hispanic)	57	24.05	22.41	24.79
Other	3	1.27	1.72	0.85
Marital Status
Married	5	2.12	3.45	0.86	0.7385
Single	62	26.27	25.86	26.72
Separated not Divorced	9	3.81	3.45	4.31
Divorced	55	23.31	23.28	22.41
Widowed	105	44.49	43.97	45.69
Social Support (Do you live)
Alone	233	98.31	97.41	99.15	0.309
Not Alone	4	1.69	2.59	0.85
Last Level of Education Completed
Grade School	33	14.04	11.21	17.24	0.2404
Some High School	65	27.66	22.41	32.76
High School Graduate	78	33.19	37.07	30.17
Some College	46	19.57	22.41	15.52
College Graduate	10	4.26	5.17	3.45
Graduate or Professional degree	3	1.28	1.72	0.86
Reported Health Status
Excellent to Good	120	50.63	62.07	39.32	0.0023
Fair to Poor	115	48.52	37.07	59.83
Don’t Know	2	0.84	0.86	0.85
Chronic Health Conditions
Diabetes	92	38.82	38.79	38.46	0.9586
Hypertension	180	75.95	73.28	78.63	0.3387

The overall and age-specific prevalence of self-reported vision impairment, eye care utilization and eye disease as addressed in the BRFSS in this sample are presented in Table 2. A third of participants (33.3%) self-reported difficulty with distance vision. Slightly more participants (38%) self-reported difficulty with near vision. The majority of participants (52.8%) had not been to see an eye care provider within the last year. A similar number (54.1%) had not had a dilated eye exam in the past year, indicating that most participants who had visited an eye care provider within the last year had received a dilated eye exam. The most common reasons provided by participants for why they had not been to see an eye care provider within the last year were that they had no reason to go (43.3%), had not thought about going (18.9%), cost (13.4%), and did not have transportation (11%). Most participants (61.6%) were aware that they had health insurance coverage for eye care with Medicare (83.5%) being the most common type of health insurance reported by participants. Rates of eye disease among this sample were as follows: 40.3% reported having cataracts, 13.6% reported having glaucoma, 4.2% reported having age-related macular degeneration, and 5.5% reported having diabetic retinopathy. There were no significant age-specific differences between groups for any BRFSS measure, except for the expected differences in health coverage noted in the 60–69 year old group which includes those ineligible for Medicare. This likely also explains why this age group had higher cost issues associated with visiting an eye care provider. Although not statistically significant, the rate of glaucoma and age-related macular degeneration increased with age, while those in the oldest age group reported the lowest rates of both cataract and diabetic retinopathy.

Table 2.

Overall and age-specific prevalence (%) for eye disease and eye care utilization

Age Range	All	60–69	70–79	≥80	p-value
Any difficulty with distance vision?
None	65.40	61.54	69.66	64.29	0.7851
A little	20.25	19.23	19.10	22.86
Moderate	7.59	10.26	4.49	8.57
Extreme	2.95	3.85	3.37	1.43
Unable due to eyesight	2.53	3.85	1.12	2.86
Don’t know	1.27	1.28	2.25	0.00
Any difficulty with near vision?
None	62.03	52.56	65.17	68.57	0.4129
A little	16.88	19.23	15.73	15.71
Moderate	9.28	15.38	7.87	4.29
Extreme	7.59	7.69	7.87	7.14
Unable due to eyesight	3.80	5.13	3.37	2.86
Don’t know	0.42	0.00	0.00	1.43
Last time visited eye care provider?
≤ 1 year ago	47.19	43.42	52.87	44.12	0.7117
> 1 year ago	50.65	53.95	44.83	54.41
Never	2.16	2.63	2.30	1.47
Reason did not use eye doctor past 12 months?
Cost/insurance	13.39	31.82	4.76	2.44	0.0039
No Eye Doctor	4.72	6.82	4.76	2.44
Could not get there	11.02	4.55	14.29	14.63
Could not get appointment	3.94	4.55	4.76	2.44
No reason to go	43.31	31.82	42.86	56.10
Did not think about it	18.90	11.36	26.19	19.51
Don’t know	4.72	9.09	2.38	2.44
When last dilated exam?
≤ 1 year ago	45.95	44.59	48.81	43.75	0.7065
> 1 year ago	50.00	50.00	46.43	54.69
Never	4.05	5.41	4.76	1.56
Health insurance for eye care?
Yes	61.60	57.69	69.66	55.71	0.3447
No	32.91	37.18	24.72	38.57
Don’t know	5.49	5.13	5.62	5.71
Kind of health coverage?
Medicare	83.54	69.23	89.89	91.43	0.0002
Medicaid	20.25	29.49	15.73	15.71	0.0465
Supplemental	27	24.36	28.09	28.57	0.8117
Other	15.61	21.79	13.48	11.43	0.1738
Don’t know	2.53	1.28	2.25	4.29	0.4977
Cataract
Yes	40.25	41.56	43.82	34.29	0.4580
No	59.75	58.44	56.18	65.71
Glaucoma
Yes	13.56	9.09	15.73	15.71	0.3778
No	86.44	90.91	84.27	84.29
Age-related macular degeneration
Yes	4.24	2.60	3.37	7.14	0.3445
No	95.76	97.40	96.63	92.86
Diabetic retinopathy
Yes	5.51	7.79	5.62	2.86	0.4234
No	94.49	92.21	94.38	97.14

Table 3 presents rates of eye care utilization, health insurance, and eye disease by self-reported vision impairment status. Chi-squared analyses revealed a few statistically significant differences between groups. Persons with vision impairment were less likely to report having seen an eye care provider within the last year than those without impairment (p=0.03); this same trend was true for dilated eye examinations but did not reach statistical significance. Those with impairment were less likely to report having Medicare (p= 0.04) and more likely to report having some other form of health insurance (p= 0.05). Those with impairment were more likely to have been told that diabetes affected their eyes (p= 0.05) (e.g. had diabetic retinopathy).

Table 3.

Rates of eye care utilization, health insurance, and eye disease by self-reported vision impairment.

BRFSS Question	All	Without Impairment	With Impairment	p-value
Any difficulty with distance vision?
≤ 1 year ago	47.19	55.26	38.94	0.0284
> 1 year ago	50.65	43.86	57.52
Never	2.16	0.88	3.54
Any difficulty with near vision?
Cost/insurance	13.39	13.21	13.89	0.5889
No Eye Doctor	4.72	1.89	6.94
Could not get there	11.02	7.55	13.89
Could not get appointment	3.94	1.89	4.17
No reason to go	43.31	50.94	37.50
Did not think about it	18.90	18.87	19.44
Don’t know	4.72	5.66	4.17
Last time visited eye care provider?
≤ 1 year ago	45.95	53.15	38.32	0.0894
> 1 year ago	50.00	43.24	57.01
Never	4.05	3.60	4.67
Health insurance for eye care?
Yes	61.60	62.07	61.54	0.9643
No	32.91	32.76	32.48
Don’t know	5.49	5.17	5.98
Kind of health coverage?
Medicare	83.54	88.79	78.63	0.0358
Medicaid	20.25	17.24	23.93	0.2068
Supplemental	27	25.00	29.06	0.4854
Other	15.61	11.21	20.51	0.0520
Don’t know	2.53	0.86	3.42	0.1781
Cataract
Yes	40.25	40.00	41.03	0.8736
No	59.75	60.00	58.97
Glaucoma
Yes	13.56	12.17	13.68	0.7333
No	86.44	87.83	86.32
Age-related macular degeneration
Yes	4.24	2.61	5.13	0.3204
No	95.76	97.39	94.87
Diabetic retinopathy
Yes	5.51	2.61	8.55	0.0493
No	94.49	97.39	91.45

Discussion

There has not been much previous research regarding the visual status and eye care utilization rates among the socioeconomically disadvantaged older adult population. This study contributes to our understanding of visual status, eye care utilization, and presence of eye disease among socioeconomically disadvantaged older adults residing in SSH. Understanding the state of vision and utilization of vision services in this population will help direct public health efforts in this area. Previous research has shown that both age, male sex, nonwhite race, lack of insurance, and lower socioeconomic status have been associated with vision impairment (Zebardast, Friedman, & Vitale, 2017; Zheng et al., 2011) and that vision impairment is a risk factor for poor self-rated health, impaired cognitive performance, anxiety, depression, and social isolation (Arokiasamy et al. 2015; Hamedani et al., 2019; Lin et al., 2004; Reyes-Ortiz et al., 2005; Wang, Mitchell, Smith, Cumming, & Leeder, 2001; Wood et al., 2005). We previously found that 40% of this population failed an objective distance vision test and 58% failed an objective near vision test (Elliott et al., 2015). Asking for residents’ self-report of their vision status allows us to recognize any disparity between their self-perceived visual function and that of objective measures. This may also allow us to understand why they may or may not be accessing eye care. Participants in this study self-reported lower levels of vision impairment than what we found using objective measures of distance and near visual acuity (33.3% vs 40% for distance; 38% vs 58% for near). These results highlight a disparity between how this group viewed their vision and what was measured objectively. This may explain why a large proportion of the residents (43.3%) who had not been to see an eye care provider cited not having no reason to go as the main reason for why they had not been to see an eye care provider. Maintaining independence is necessary to remain in SSH as no formal health care assistance is provided in these residential communities, therefore, it is possible that rates of self-reported vision impairment were lower than objectively measured rates if residents were concerned about their vision affecting these independence requirements. However, rates of very low vision/blindness were very low and the vision impairment found in this study was unlikely to have affected residents’ ability to live independently.

The majority of our participants were African American, a population at higher risk for developing hypertension and diabetes; conditions for which there are vision-related sequelae (American Heart Association, 2015; Centers for Disease Control and Prevention, 2015). In our sample, 39% self-reported having diabetes and 76% self-reported having hypertension. It is important for people with these chronic diseases to receive regular eye examinations. The American Academy of Ophthalmology (AAO) (2015) recommends that all older adults with diabetes and/or hypertension have an eye exam at least annually or more frequently if recommended. Furthermore, AAO (2015) recommends that all people ages 65 and over have an eye exam every 1 to 2 years even in the absence of risk factors or symptoms.

In our sample, the rate of self-reported impairments for distance and near vision were 33.3% and 38% respectively. This is higher than previous research using the same BRFSS questionnaire in a national sample of adults over 50 years of age, where the self-reported rates of distance and near vision impairment were 16.6% and 32.8% respectively (McGwin, Khoury, Cross, & Owsley, 2010). It is not surprising that higher rates of perceived vision impairment were noted in our study since this sample was comprised of older persons (60+) with less socioeconomic means than those surveyed by the BRFSS nationally (McGwin et al., 2010). Our findings are consistent with research indicating that both increased age and lower socioeconomic status may be associated with higher rates of vision impairment (Zheng et al., 2011). The rates of cataract and glaucoma found in the present sample (40.3% and 13.6%) were higher than those found by McGwin and colleagues (2010) using the BRFSS on a national level (19.6% and 6.4%). Given that our sample was largely African American, it is not surprising that our rates of glaucoma were twice as high as those in the national sample as glaucoma is more prevalent in African Americans than Whites and Hispanics (Friedman et al., 2004). Unsurprisingly, our participants reported lower rates of age-related macular degeneration than the national sample (4.2% vs. 5.8%) as macular degeneration is more commonly found in people of European ancestry than of African descent (Jonas, Cheung, Panda-Jones, 2017). Diabetic retinopathy was self-reported by 5.5% of participants in our study, this is slightly higher than previous general population estimates of diabetic retinopathy of 3.4% among U.S. adults age 40 and over (Kempen et al., 2004)

Over half of our sample had not been to see an eye care provider within the last year. This is higher than the rates that McGwin and colleagues (2010) report where one-third of a national sample reported not visiting an eye care provider within the last year. Both nationally and in the present study, the majority of people cited not having a reason to go to the eye care provider as the primary reason for not seeking an eye examination (49% nationally, 43.31% present study) (McGwin et al., 2010). The second most frequent reason cited by participants in the present study for not visiting an eye care provider was that they had not thought of it (18.9%). This was substantially higher than what McGwin and colleagues (2010) found in the national data set (6.7%). This is an important finding considering the high rate of hypertension and diabetes in this sample as people with these chronic conditions should be educated on the importance of having at least an annual dilated eye examination (AAO, 2015). This may indicate that public health efforts to increase awareness of the importance of routine eye care visits may be lacking in this group of older adults. In the present study a much higher percentage of persons reported that transportation was a major reason for not going to the eye care provider (11.02%) than what was found in national data (1.9 %) (McGwin et al., 2010). This highlights a concern for this specific population who may recognize the need for eye care but are unable to access it due to limited transportation options. While cost was one of the largest factors for not visiting an eye care provider for our participants aged 60–69, this decreased significantly as age increased likely due to this age group containing those ineligible for Medicare. However it is unknown if having Medicare was why participants in older age groups were less likely to report cost as a factor as Medicare does not cover routine eye exams. Medicare part B will cover a yearly eye exam for people with diabetes, a yearly glaucoma test for those at risk, cataract surgery, and some macular degeneration treatments (Centers for Medicare and Medicaid Services, n.d.). A recent examination of receipt of eye care worldwide found that only greater wealth was associated with having had a recent eye exam while factors such as worse memory, social isolation, and no health insurance were associated with lower rates of recent eye exams and higher rates of vision impairment (Ehrlich, Stagg, Andrews, Kumagai, & Musch, 2019).

Participants who reported vision impairment were more likely to have fair or poor subjective health (59.8%) compared to the 37.1% who did not report vision impairment. In the Blue Mountains Eye Study, Wang and colleagues (2000) also found that people with vision impairment were more likely to report fair or poor subjective health (35.5% with mild impairment and 48.8% with moderate or severe impairment) than those without vision impairment (24.5%). These findings show that vision impairment has a significant effect on how older adults perceive their health status.

Interestingly, in our sample, people who self-reported vision impairment (38.9%) were less likely to have received an eye exam within the last year as compared with those who did not self-report vision impairment (55.3%). This may be reflective of the benefits of having received eye care in that people who did see the eye care provider were then not reporting vision impairment. Alternatively, since the group who reported vision impairment were more likely to self-report having diabetic retinopathy than those who did not report impairment, it would be important to make certain that anyone self-reporting vision impairment was educated on the need for regular eye examinations, especially those who have chronic conditions with potential for vision-related sequelae.. Every participant in our study was asked if they had an eye care provider and were provided with a list of local eye care providers if they needed a provider.

This study uses self-reported data which may be subject to participant recall bias. However, previous research has indicated that older adults are capable of providing reliable self-reports of their chronic conditions, especially diabetes, but may underreport disease presence (Goldman, Lin, Weinstein, & Lin, 2003; Leikauf & Federman, 2009; Wu, Li, & Ke, 2000). Additionally, using the BRFSS, a well-designed and validated survey, contributes to the strength of these results. The sample selected for this study may not reflect the larger general population of older adults residing in SSH as participants who came to the vision screenings may have been more concerned about their vision than other residents. However, our study was designed to evaluate the vision impairment and eye care utilization rates in an understudied and potentially underserved population and we found a notable amount of vision impairment and low use of vision health services. It is hoped that this study will aide in directing eye health initiatives within Jefferson County as well as inform public health efforts in regards to vision health surveillance. While participation rates varied among individual facilities, nearly all (14 of 19, 74%) facilities approached for participation were interested in and participated in the vision screenings. Future studies investigating the eye care utilization of socioeconomically disadvantaged older adults should begin to develop strategies to increase both public health awareness of and access to eye care. It is a limitation of this study that we did not include mental health outcomes. Previous work done by our group (Owsley et al., 2007) found that vision improving interventions (cataract surgery) improved psychological distress in nursing home residents, showing that mental health may improve in response to improvement in vision. It is important to consider both the physical and mental health sequelae of vision impairment (e. g., ADL limitations, social isolation, cognitive impairment, anxiety, and depression, among others) when designing intervention studies aimed at improving vision and investigators should monitor the effect of the intervention on these outcomes.