EliScholar – A Digital Platform for Scholarly Publishing at Yale January 2020 Factors Influencing The Receipt Of Diabetic Retinopathy Screening In A High-Risk Population Elizabeth Ann
The Diabetes Epidemic
Diabetes mellitus is rapidly expanding in the United States and worldwide, prompting some experts to call it the largest epidemic in human history Past projections have underestimated how many people would develop diabetes; in 2000 the World Health Organization forecast 366 million people worldwide living with diabetes by 2030, but by 2015 the total had already reached 415 million In the United States alone, about 30 million people had diabetes in 2015, representing roughly 9.4% of the population The World Health Organization also reports that 1.6 million deaths in 2016 were directly attributable to diabetes.
Diabetes mellitus is a chronic metabolic disease defined by elevated blood glucose that gradually damages both large and small blood vessels throughout the body, leading to serious complications such as cardiovascular disease, stroke, kidney disease, and limb amputations Type 2 diabetes, characterized by insulin resistance, is the most common form, while Type 1 diabetes (often called juvenile diabetes) results from impaired insulin production The risk factors for Type 2 diabetes are diverse, with obesity, physical inactivity, and poor diet showing clear associations with increased risk, and lifestyle interventions addressing these factors have been shown to reduce diabetes incidence In addition to modifiable factors, non-modifiable determinants such as genetic susceptibility and epigenetic changes are increasingly recognized as influencing risk.
Diabetes affects different racial and ethnic groups unevenly According to the Centers for Disease Control and Prevention, in 2015 the prevalence was 12.7% among non-Hispanic Blacks, 12.1% among Hispanics, 8% among Asians, and 7.4% among whites American Indians/Alaska Natives had a prevalence of 15.1%, more than double that of whites Indigenous people are disproportionately affected by diabetes.
Aboriginal Australian and Native American communities have some of the highest diabetes prevalence rates in the world, highlighting stark ethnic disparities in this chronic disease Moreover, Black, Hispanic, and Native American people are more likely than their white counterparts to experience diabetes-related complications, such as diabetic retinopathy, underscoring the need for targeted prevention and improved access to care in these populations.
Diabetic Retinopathy
Diabetic retinopathy is a microvascular and neurodegenerative complication of diabetes driven by chronic hyperglycemia, which triggers inflammation, oxidative stress, and advanced glycation end products in the retina, leading to vascular damage and neuroretinal dysfunction In its non-proliferative stages, retinal endothelial injury causes microhemorrhages, microaneurysms, retinal infarcts, and leakage of lipids and plasma proteins that can result in macular edema and vision loss when the macula is affected As non-perfusion progresses, abnormal retinal neovascularization develops, giving rise to proliferative diabetic retinopathy where new vessels invade the vitreous, causing traction on the retina and possible detachment, with fragile vessels prone to hemorrhage and further vision loss This disease trajectory is a major cause of severe vision impairment, and it also signals systemic vascular risk, being associated with a substantially higher risk of stroke, coronary artery disease, and heart failure.
Diabetic retinopathy (DR) affects an estimated 93 million people worldwide, including about 28 million with vision-threatening DR In the United States, DR is a leading cause of vision impairment and blindness, with the prevalence among people with diabetes around 30% DR can occur in both type 1 and type 2 diabetes: nearly all individuals with type 1 diabetes will eventually develop retinopathy, and 50–60% of those with type 2 diabetes will experience some degree of retinopathy during their lifetime At the time of diabetes diagnosis, up to 21% of people with type 2 diabetes already have retinopathy, and about one in ten people with diabetes will develop a vision-threatening form of DR.
There are a number of risk factors for DR that are well-documented, including poor glycemic control, poor blood pressure control, and a longer duration of diabetes
While these factors explain only part of the risk for diabetic retinopathy, much of the remaining risk remains poorly understood Socioeconomic factors can profoundly affect the health of people with diabetes and their ability to influence related risk factors Socioeconomic status shapes multiple aspects of the patient experience, including access to medical care, community resources, social support, diabetes knowledge, communication with providers, and adherence to treatment plans The living environment also influences diabetes risk and its complications; for instance, residing in safe, walkable neighborhoods with access to healthy foods can impact disease management and outcomes.
Paralleling the racial disparities in the prevalence of diabetes, racial and ethnic minorities are also at increased risk of developing DR and vision-threatening forms of
DR [2,18–20] In one study that examined the third National Health and Nutrition
NHANES III data indicate racial disparities in diabetic retinopathy (DR) prevalence Non-Hispanic Blacks have a 46% higher DR prevalence than non-Hispanic Whites, and Mexican-Americans have an 84% higher prevalence For Native Americans, studies are limited; earlier reports from the 1980s and 1990s documented DR prevalence ranging from 38% to 59%, while a more recent study places DR prevalence at 20%.
Prevention and Treatment of Diabetic Retinopathy and the Role of Screening
Blindness from diabetic retinopathy is largely preventable, yet about 10% of people with diabetes will develop vision-threatening DR Diabetic retinopathy, like many eye diseases, has no early symptoms or warning signs, so many patients are unaware they have it NHANES data from 2005–2008 show that among those with retinopathy evident on fundus photographs, only 26.1% said a doctor had told them diabetes had affected their eyes or that they had retinopathy, and among those with diabetic macular edema, only 44.7% answered yes.
Intensive glycemic and blood pressure control lowers the risk of developing diabetic retinopathy (DR) and slows its progression A 1% reduction in HbA1c reduces retinopathy risk by about 40% Tight blood pressure control to below 150/85 mm Hg decreases DR progression by roughly one-third For proliferative DR, vision-preserving treatments include panretinal laser photocoagulation and intravitreal anti-VEGF therapy, both aimed at reducing pro-angiogenic signaling and retinal neovascularization; anti-VEGF therapy can also treat diabetic macular edema, sometimes with intraocular steroids In cases of tractional retinal detachment or persistent vitreous hemorrhage, vitrectomy may be necessary Overall, these DR treatments are highly effective and can reduce severe vision loss by about 50–94%.
Early detection of diabetic retinopathy through routine eye examinations and timely treatment is key to preventing major vision loss Screening for diabetic retinopathy is justified because it is highly prevalent among people with diabetes, the early disease is asymptomatic yet detectable with screening methods, and there are effective treatments that can reduce disease burden Additionally, screening is a cost-effective intervention, saving approximately $100 million in federal dollars each year.
Screening guidelines state that patients with type 2 diabetes should be screened for diabetic retinopathy with a comprehensive dilated eye examination at diagnosis and then annually thereafter Adults with type 1 diabetes should begin annual screening after five years of disease duration While an ophthalmologist’s clinical examination would be ideal, practical limitations hinder universal in-clinic screening Non-mydriatic digital retinal photography offers a scalable solution for large-scale screening of diabetic retinopathy.
Diabetic retinopathy (DR) screening can be conducted in primary care settings using retinal photographs that are transmitted to reading centers for evaluation If DR is detected, appropriate referrals to an ophthalmologist are initiated to ensure timely care and management.
Utilization of Screening for Diabetic Retinopathy
Despite the critical role of annual diabetic retinopathy screening in enabling early treatment and preventing vision loss, non-adherence remains high, with estimates showing that 35–50% of patients with diabetes do not receive the necessary screening Factors associated with receiving appropriate screening and overall eye care utilization include socioeconomic status, insurance coverage, access to care, and race/ethnicity.
Socioeconomic status influences access to preventive eye care Among patients with age‑related eye diseases (age‑related macular degeneration, cataract, diabetic retinopathy, or glaucoma), those with lower income or less than a high school education were less likely to have had an eye examination in the past year Zhang et al reported these income and education–related gaps in eye care, and Chou et al., using the 2006–2009 Behavioral Risk Factor Surveillance System data, found similar disparities along income and educational lines.
Insurance status A study by Lee et al used data from the National Health
An interview survey examined eye care utilization and found that among people without insurance, utilization rates were 14% for no visual impairment, 24% for some impairment, and 36% for severe impairment By contrast, insured individuals had significantly higher utilization at 34% for no impairment, 54% for some impairment, and 60% for severe impairment, illustrating how insurance status influences access to eye care.
Analyses of the Expenditure Panel Survey Household Component (2002–2009), which includes the Diabetes Care Survey, show that having health insurance is the single most important factor in receiving an eye examination Nonetheless, the study highlights racial and ethnic disparities in eye care access that persist even among insured individuals [36].
Access to care remains uneven, with rural residents showing lower eye care utilization, underscoring gaps in preventive eye health services Native American communities face well-documented barriers to healthcare access and utilization that persist even among those living in urban areas, highlighting the need for targeted, culturally competent strategies to improve access and health outcomes.
Race and ethnicity are consistently linked to disparities in eye health, with racial/ethnic minority status associated with decreased utilization of eye examinations and reduced access to eye care Research has shown that certain Hispanic subgroups, including Mexican Americans and Cuban Americans, have lower rates of eye care utilization compared with other populations.
A population-based survey in Maryland of individuals aged 65–84 shows racial disparities in eye-care utilization: only about half of Black participants reported seeing an eye doctor in the past year, compared with 69% of White participants In a separate study at a large Indian Health Service clinic, adherence to diabetic retinopathy (DR) screening was 50%, but rose to 75% after implementing a digital retinal imaging system in the primary care setting.
Purpose of Current Study
Evidence from the literature shows that populations bearing the greatest burden of diabetic retinopathy—especially racial and ethnic minorities and individuals with low socioeconomic status—are the least likely to receive essential screening examinations In other words, those who would benefit most from screening are often the ones who do not obtain it This pattern reflects a complex interplay of biological, socioeconomic, and environmental factors that influence both the risk of diabetes and its complications and the utilization of screening services.
Understanding and intervening upon these factors is key to improving outcomes for patients with diabetes
Although a wealth of data shows disparities in diabetic retinopathy (DR) screening utilization, relatively few studies examine patient perspectives, especially among high-risk populations such as racial/ethnic minorities and those with low socioeconomic status Prior focus-group studies on eye health have identified barriers including cost and insurance status, transportation, poor communication with physicians, distrust of the healthcare system, the burden of systemic disease, absence of symptoms, and a perceived lack of need for an examination In North Carolina, Elam and Lee found distrust in the provider or the healthcare system to be the most common barrier among under-utilizers of eye care Alexander et al reported that participants across racial groups generally lacked knowledge about eye health and that primary care providers rarely counseled patients about eye care Fisher et al showed that patients with diabetes most commonly cited unawareness of insurance benefits as a barrier to dilated eye exams, whereas physicians identified a lack of education about the importance of eye exams as the main barrier.
Research focusing on the experiences of diabetes patients at higher risk for vision loss—racial and ethnic minorities and those with low socioeconomic status—is needed to understand how this population engages with diabetic eye care Understanding the factors that influence receipt of eye care among high-risk patients is key to designing effective interventions that boost DR screening uptake and reduce the burden of diabetic retinopathy In this study, we present findings from individual qualitative interviews with high-risk diabetic patients at a federally qualified community health center about their use of diabetic retinopathy screening, and we propose a theoretical framework to characterize the factors that influence receipt of diabetic eye care in this population.
I Qualitative Methods and Their Utility
Qualitative research is research that attempts to answer why or how a phenomena occurs using non-numerical data It typically uses inductive rather than deductive reasoning and seeks to generate rather than test hypotheses [46] Qualitative methods may be useful in describing a range of phenomena, as Curry et al describes:
“Although quantitative methods have historically been the primary approach in health sciences research, many contemporary phenomena in health and health care are difficult, if not impossible, to measure using quantitative approaches alone Examples include complex and dynamic social processes; beliefs, values, and motivations that underlie individual health behaviors; and social, political, economic, and organizational contexts relevant to health…The goal is to produce depth of understanding, and perhaps generate hypotheses regarding a phenomenon, its precursors, and its consequences [46].”
Qualitative methods provide a way to explore the diverse experiences of patients, including those from at-risk communities In qualitative research, data are collected through observational and descriptive approaches such as one-on-one interviews or focus groups, using purposeful sampling to select individuals with direct experience or knowledge of the topic Analysis proceeds in iterative cycles where data are collected, coded, and interpreted, and the products of this analysis commonly include recurrent themes, developing hypotheses, or conceptual models.
This study investigates the factors influencing diabetic retinopathy (DR) screening uptake among patients from racial/ethnic minority groups and those with low socioeconomic status Given the complexity of DR screening decisions, qualitative methods are well suited to illuminate the personal choices, beliefs, barriers, and contextual factors that shape individual patients’ decision-making about screening.
This study adopts grounded theory, a systematic approach in which theory emerges from inductive reasoning applied to the collected data As qualitative data are reviewed, recurring concepts are coded and refined as more data are gathered and codes are re-examined The codes are then organized into concepts and broader categories that can form the basis for a new theory This approach enables the researcher to develop a theoretical account of the general features of a topic while grounding that account in empirical observations or data [47][48].
Setting
Yale University's Institutional Review Board approved the study protocol and exempted it from ongoing oversight Insights from leaders of local community health organizations, gathered through the Yale Center for Research and Engagement, informed the study design The center's mission is to facilitate collaboration between community organizations and trainees to design and implement research projects on topics identified as priorities by the New Haven community [49].
Semi-structured, qualitative interviews were conducted with diabetes patients at the Cornell Scott Hill Health Clinic, a federally qualified health center (FQHC) in New Haven, Connecticut, and at its satellite clinics in New Haven and nearby areas.
Additional interviews were conducted at the Yale Primary Care Clinic in New Haven, CT, following earlier work in Ansonia, CT The FQHC serving these clinics reports a patient population that is 69% Black or Latino, with 64% of patients living below the poverty line [50], and the Yale Primary Care Clinic serves a similar demographic profile The interview settings included primary care clinics, a diabetes/wellness education center, and an on-site eye clinic.
Participants
A convenience sample of English-speaking patients with diabetes was recruited by approaching patients before or after their appointments Author E Fairless recruited
Thirty participants were enrolled, with A King, a medical student, among the recruiters who helped enroll the final six participants All participants provided written informed consent and consent to be audio-recorded No compensation was given to the first 24 participants, while the last six received $20 gift cards for their time Eligibility required a diabetes diagnosis for at least one year Self-reported demographic information collected included age, gender, race/ethnicity, insurance status, time since diabetes diagnosis, time since last eye exam, and frequency of eye exams.
Participant Interviews
Semi-structured qualitative interviews were conducted in English with participants in a one-on-one setting E Fairless conducted 24 of the 30 interviews, while A King conducted the remaining six Grounded theory guided the study, with the aim of generating hypotheses rather than testing a predetermined hypothesis Participants were asked open-ended questions about their experiences with eye exams, the factors that influenced their decision to pursue or forego an eye exam, and any barriers they faced in accessing eye care E Fairless developed the interview guide used to direct questioning (Table 1).
When was the last time you had an eye exam? How often do you get eye exams?
Can you tell me about your experience the last time you had an eye exam?
What made you decide to get an eye exam? What motivated you to go?
At the time that you were diagnosed with diabetes, what, if anything, were you told about eye care?
Have you ever been told by a healthcare provider that diabetes can affect your eyes?
How did you learn that diabetes can affect your eyes?
Has anything ever prevented you from having an eye exam? Have you ever cancelled or not shown up to an eye exam appointment? If so, why?
Follow-up questions were used to encourage participants to elaborate as needed, and the interview guide was periodically re-evaluated and rephrased by the author using a reflection checklist to ensure clarity and internal validity.
Data Analysis
Interviews were conducted by E Fairless and recorded with a Zoom H4n Handy Recorder, then transcribed verbatim using Trint and analyzed with NVivo 11 (QSR International) The qualitative analysis followed grounded theory methods: transcripts were reviewed line by line, codes were generated inductively to define concepts from the data, and coded text was iteratively reviewed to identify overarching themes and refine codes until a final, comprehensive coding framework emerged All interviews were reviewed and coded by E Fairless, with Dr K Nwanyanwu providing a review of the transcripts and coding.
Fairless and Nwanyanwu developed a coding framework that underpins a theoretical model of the factors influencing screening utilization The framework’s core themes are organized into a socio-ecological model that locates health behaviors within three interconnected levels: individual factors (such as attitudes and behaviors), social factors (including networks and social support), and structural factors (such as access to care), collectively shaping screening uptake [52,53].
Participant Demographics
A total of 30 people participated in the study The median age of participants was 57.3 (range 35 –73) Fifteen participants identified as female and 15 as male
The study sample comprised 30 participants with racial/ethnic distribution of Black (16), White (5), Hispanic (5), Asian (1), and other/declined to answer (3) Health insurance coverage was reported by 28 participants Eye-exam history shows that 24 participants had an eye exam in the past year, while one-third (10) reported not receiving an eye exam yearly Diabetes duration indicated that half of participants had diabetes for more than 10 years These demographic characteristics are summarized in Table 2.
Demographic Information N = 30 Age, median (range) 57.3 (35-73)
Most Recent Eye Exam, No (%)
Within previous 12 Months 24 (80) Not within previous 12 months 6 (20)
Annually or more frequently 20 (66) Less frequently than annually 10 (33)
Interview Comments
In a qualitative analysis of 415 interview comments, we coded the data into 22 nodes across seven themes, which were then categorized as either individual factors or institutional and structural factors based on a socio-ecological model The individual factors encompassed vision status, competing concerns, and emotional context, while the institutional and structural factors included resource availability, in-clinic experience, cues to action, and knowledge-creating experiences This coding framework subsequently became our theoretical model of the factors affecting the utilization of eye examinations in our patient population (Figure 1).
Figure 1: Theoretical framework of factors affecting utilization of eye exams in patients with diabetes, and representative quotes from participants
Individual factors encompass patient-specific elements, including vision status, competing concerns, and emotional context, as well as attitudes and behaviors, health issues, and other factors closely tied to daily life that can influence outcomes.
Vision status drove many participants to seek an eye exam, with changes in vision or the need for updated corrective lenses as the main motivators One participant with diabetic retinopathy recalled delaying care until a retinal hemorrhage affected his vision, noting that after initially missing the appointment he was “half-blind, so I saw the doctor properly.” Another said it wasn’t until he noticed a difference in his own eyesight that he wanted to get an exam In addition to disease screening, several participants indicated that updating glasses annually served as an independent incentive to seek eye care A participant with gout described the challenge of reaching the eye clinic due to foot pain but pushed through because he wanted some new glasses.
Participants cited barriers to regular eye exams, including other health problems, childcare responsibilities, struggles with addiction, and unstable employment schedules that pull attention away from preventive vision care One participant recalled that a new job disrupted her appointments and led to several cancellations over the last three months: “I canceled a few appointments over the last three months because I had a new job So now I'm going to work on getting all those appointments rescheduled and done because I'm not working now.” She noted that being out of work offers an opportunity to reschedule and complete overdue eye exams.
Emotional context strongly influenced decisions about seeking eye exams Some participants reported fear or hesitation, worried about receiving bad health news or about painful procedures, even saying they avoided exams to keep the possibility of a diagnosis at bay—“I didn't think I needed [an eye exam] And a lot of times when I go to the doctor all of the sudden I need stuff And I didn't want that to happen, I wanted to think that my eyes were going to be OK.” In contrast, others were motivated by a desire to stay informed about their health, viewing eye exams as proactive care, especially after major health events such as hospitalization that served as a wake‑up call to access healthcare.
Institutional and structural factors influencing eye care receipt include resource availability, in-clinic experience, cues to action, and knowledge-creating experiences These factors relate to the patient-provider relationship, the healthcare system, and broader social structures, and collectively shape access to eye care by determining how patients engage with services, the quality of care they receive, and the information that motivates their eye health decisions.
Resource availability, including insurance status and the cost of an eye exam, emerged as a key factor influencing access to eye care, especially for participants who had not had an eye exam in the past year; for example, a single parent of three explained that she didn’t return to the eye clinic because she couldn’t afford the required payment, even though she knew an exam was important, and another patient described avoiding care despite ongoing eye symptoms due to financial constraints Uninsured status was also a major barrier, with one participant noting a five-year gap in eye exams because she couldn’t find a clinic that would treat someone without insurance and because her income created a coverage gap—she earned too much for state Medicaid but not enough to afford employer coverage Additionally, several participants reported getting eye exams only every two years, under the impression that annual exams were not covered by their insurance, even though medically necessary eye exams for patients with diabetes are typically covered annually by most plans.
Access to transportation to the eye clinic emerged as an important factor in seeking eye care, even though most participants reported no issues finding adequate transport Homelessness and incarceration, however, could prevent individuals from getting eye exams, as illustrated by one participant who noted eye care was not provided during incarceration: “I was in prison, so they didn’t— they don’t do all that [eye care] So when I came home I got everything done.”
In-clinic experiences show that how clinicians communicate with patients can drive whether people keep up with eye care, for better or worse One patient described a positive encounter: diabetes had not affected her eye health so far, based on the doctor’s explanations during visits; she felt the process worked, with yearly full workups that reassured her nothing significant was happening By contrast, another participant noted receiving conflicting information from different providers, illustrating how mixed messages can undermine trust and adherence.
Today I’m still dealing with blurred vision, and I’m hearing mixed messages about what it means Some people say it’s nothing to worry about, others suggest there could be an issue, and one person mentions a trace of cataract but tells me not to worry Because the blurry vision comes and goes, I’m unsure what steps to take next to protect my eye health and whether I should seek a professional evaluation from an ophthalmologist.
Participants described episodes of clear miscommunication in eye care, including a patient awaiting retina surgery who wrongly believed the doctors would remove his eye to perform the procedure They also indicated that feeling respected by their eye doctor and having positive interactions with clinic staff were important factors shaping their overall experience with eye care.
Cues to action from primary care providers strongly influence patients’ decisions to seek an eye examination Participants reported that a PCP’s prompt to have an eye exam significantly increased their likelihood of following through, even when diabetes was not present One participant stated: “If the doctor would suggest me have an eye exam, regardless of whether I had diabetes or not I would have followed out the instructions.” This underscores how clinician recommendations can boost eye health screening uptake and highlights the role of primary care in encouraging regular eye examinations, regardless of diabetes status.
If I were on my own, I don't think I would have acted This is illustrated by another participant's experience, who reported being told about the importance of an eye exam and being appropriately referred for further evaluation The example shows how clear guidance and timely referrals can prompt individuals to seek essential eye care that they might not pursue without support.
My doctors told me I needed an eye exam to check for any damage to my eyesight caused by diabetes and high blood pressure They referred me, set up the appointment, and after the visit I only received a phone call with instructions to come in.
In contrast, another participant felt that eye care was not emphasized by his primary care provider, which delayed his seeking an eye exam:
“I should have been scared into going [to the eye doctor] a little bit, or at least, you know, given some kind of explanation as to what [diabetic retinopathy] was
Diabetes comes with a long list of side effects, including neuropathy, and I deal with many of them every day Yet, for some reason, my eyes seem to be at the bottom of that list.
Participants also reported that following an annual exam schedule and getting appointment reminders were useful prompts to seek eye exams