Diabetic Retinopathy Screening

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Diabetic Retinopathy Screening

Disease

Diabetic retinopathy (DR) is the leading cause of preventable blindness.1 Of working-age Americans diagnosed with Diabetes Mellitus, it is estimated that about 1/3 have diabetic retinopathy (DR) and 4.4% have vision threatening retinopathy.2,3 For more information on diabetic retinopathy disease and pathophysiology, see Diabetic Retinopathy and Diabetic Retinopathy Pathophysiology.

Screening Methods

The most recent guidelines for DR screening were released by the International Council of Ophthalmology (ICO) and American Diabetes Association (ADA) in 2018.4 This article focuses on DR screening in the United States. Other guidelines are specific to a given country and limited to high resource settings.5–7

The method used to screen for DR is dependent on resource settings. The 2018 ICO/ADA guidelines state that adequate DR screening should include a visual acuity exam and a retinal examination.

Adequate visual acuity screening includes at least one of the following:

(1) refracted visual acuity examination using 3- or 4-m visual acuity lane and a high-contrast visual acuity chart

(2) presenting visual acuity examination using a near or distance eye chart and pin-hole option if visual acuity is reduced

(3) presenting visual acuity examination using a 6/12 (20/40) equivalent handheld chart consisting of at least 5 standard letters or symbols and a pin-hole option if visual acuity is reduced.

Adequate retinal examination includes at least one of the following:

1) direct or indirect ophthalmoscopy or slit-lamp biomicroscopic examination of the retina

(2) retinal (fundus) photography, including any of the following: 30° to wide field, monophotography or stereophotography, and dilated or undilated photography.4

Retinal examination can be performed by individuals without a medical degree, so long as they are trained to perform ophthalmoscopy or retinal photography and can assess disease severity.4

Screening Rates in the United States and Impact of Social Determinates of Health

Despite the high prevalence of DR, only 62.3 percent of patients with diabetes in the United States receive annual screening exams.8,9 Screening rates within subsets of the US population vary greatly. Social determinates of health have an important role in DR screening rates. Numerous studies have identified lower educational status, lower income, minority race, recent immigration, residence in a rural community, and lack of health insurance with significantly decreased rates of DR screening.2,10–18 Income is a particularly important factor, as patients of lower socioeconomic status are less likely to receive eye care.19 Patients of minority race and ethnicity, including Black and Hispanic patients, are less likely to be aware of their diagnosis of DR and to receive screening.20,21 Residence in a disadvantaged neighborhood is associated with decreased likelihood of adherence to DR screening.22 Health insurance status was found to have the most profound effect on DR screening rates, with 76% of patients with insurance receiving proper screening while only 36% of uninsured patients received proper screening.11Patients who do not receive eye care often lack trust in the medical system.23

Increasing DR screening rates is an important goal of the US Department of Health and Human services Healthy People 2030 campaign. The DR goals for Healthy People 2030 include increasing DR screening in people with diabetes from 62.3 percent to 67.7 percent and reducing vision loss from DR from in people with diabetes from 33 percent to 16.5 percent.9,24

Screening Follow-up

Screening follow-up depends on the severity of disease as well as the available referral resources in a given geographic location. Table 1 summarizes the follow up on DR screening according to the ICO/ADA 2018 guidelines in high resource settings. Table 2 summarizes the management of DR in high resource settings according to the ICO/ADA 2018 guidelines.4

Table 1: ICO/ADA 2018 DR screening follow-up guidelines for high resource settings

Classification Re-examination or Next Screening Schedule Referral to Ophthalmologist
Diabetic Retinopathy (DR)
 No apparent DR, mild nonproliferative DR, and no DME Re-examination in 1–2 yrs Referral not required
 Mild nonproliferative DR 6–12 mos Referral not required
 Moderate nonproliferative DR 3–6 mos Referral required
 Severe nonproliferative DR <3 mos Referral required
 Proliferative DR <1 mo Referral required
Diabetic Macular Edema (DME)
 Non–center-involving DME 3 mos Referral required
 Center-involving DME 1 mo Referral required

Table 2: ICO/ADA 2018 DR Management guidelines for high resource settings

Disease Follow-up Schedule for Management by Ophthalmologists
DR severity
 No apparent DR Re-examination in 1–2 yrs; this may not require re-examination by an ophthalmologist
 Mild nonproliferative DR 6–12 mos; this may not require re-examination by an ophthalmologist
 Moderate nonproliferative DR 3–6 mos
 Severe nonproliferative DR <3 mos; consider early panretinal photocoagulation
 PDR <1 mo; consider panretinal photocoagulation
 Stable (treated) PDR 6–12 mos
DME severity
 Non–center-involving DME 3–6 mos; consider focal laser photocoagulation
 Center-involving DME 1–3 mos; consider focal laser photocoagulation or anti-VEGF therapy

Resource-Limited Settings and Cost Effectiveness

Dilated fundus exam performed by an ophthalmologist is considered the gold standard method for diagnosing DR and monitoring patients at risk of developing DR; however, a yearly exam in a resourced-limited setting would prove unfeasible given the growing gap in access to eye care professionals.25 With recent advances in technology, most screening programs are transitioning to retinal photography-based screening.26 Recent studies have indicated that photography screening programs are cost effective for populations with over 3,500 individuals aged 50-80 and can generate a savings of $127 per individual with diabetes screened over their lifetime.27 Kahn et al. demonstrated this cost savings could be achieved with only 65% of individuals completing screening.28

Overall, the ICO recommended screening and referral guidelines only differ to a minor extent for limited resource areas. Longer screening intervals can be used for low-risk individuals in the mild and moderate NPDR categories, while more severe disease has the same recommended interval (Table 3).4 Additionally, non-center involving DME treatment may be delayed in settings where access to laser therapy is limited.

Table 3: ICO/ADA 2018 DR screening follow-up guidelines for low-intermediate resource settings

Classification Re-examination or Next Screening Schedule Referral to Ophthalmologist
Diabetic Retinopathy (DR)
 No apparent DR, mild nonproliferative DR, and no DME Re-examination in 1–2 yrs Referral not required
 Mild nonproliferative DR 1—2 yrs Referral not required
 Moderate nonproliferative DR 6-12 mos Referral required
 Severe nonproliferative DR <3 mos Referral required
 Proliferative DR <1 mo Referral required
Diabetic Macular Edema (DME)
 Non–center-involving DME 3 mos Referral not required (referral recommended if laser sources available)
 Center-involving DME 1 mo Referral required

Tele-retina and Artificial Intelligence

Tele-retina has been proposed as a cost-effective alternative to examination by an ophthalmologist27,29, whereby retinal images taken at one site are transmitted to and interpreted at another site. Non-mydriatic photography can be accomplished with minimal training in the primary care setting28 and may demonstrate similar sensitivity and specificity (78-98%, 86-90%, respectively) to a dilated fundus exam performed by an ophthalmologist (84-92%, 92-98%, respectively).30 While there are benefits including reduced need for dilating medications and easy image acquisition, there are reports of high technical failure rates and the continued reliance on a trained image grader.27 Consistent follow up on screening results is necessary for an effective tele-retina program, and health systems must be prepared for the upfront costs of increased patient volume at the eye clinics.31 Ultimately, the long-term savings from earlier disease diagnosis and treatment far outweigh the up-front cost.31

With the increase in incidence of Diabetes Mellitus in the United States32, artificial intelligence (AI) solutions to detecting DR are of increasing interest. These technological solutions reduce the need for trained graders in the primary care setting and enable more efficient screening. AI reduces burden of manual review of fundus photography, using technology to automatically screen fundus images for presence of disease. A systemic review of AI performance in DR screening demonstrates these technologies have high sensitivity (87.0%-95.2%) but low specificity (49.6–68.8%).33 Predictive modeling is increasingly being used to identify patients at risk of DR progression and define personalized screening intervals.34,35 While the personalized screening intervals may perform better than the low-resource extended intervals, they have a slightly higher implementation cost.35 Patients’ acceptability, patients’ confidentiality, and medico-legal challenges are issues facing widespread adoption of these technologies.36 Nevertheless, the need for more efficient screening for DR in a growing population with Diabetes Mellitus shows promise for such technologies.

References

1.         Cheung N, Mitchell P, Wong TY. Diabetic retinopathy. Lancet. 2010;376(9735):124-136. doi:10.1016/S0140-6736(09)62124-3

2.         Zhang X, Saaddine JB, Chou CF, et al. Prevalence of Diabetic Retinopathy in the United States, 2005–2008. JAMA. 2010;304(6):649-656. doi:10.1001/jama.2010.1111

3.         Yau JWY, Rogers SL, Kawasaki R, et al. Global prevalence and major risk factors of diabetic retinopathy. Diabetes Care. 2012;35(3):556-564. doi:10.2337/dc11-1909

4.         Wong TY, Sun J, Kawasaki R, et al. Guidelines on Diabetic Eye Care: The International Council of Ophthalmology Recommendations for Screening, Follow-up, Referral, and Treatment Based on Resource Settings. Ophthalmology. 2018;125(10):1608-1622. doi:10.1016/j.ophtha.2018.04.007

5.         Hooper P, Boucher MC, Colleaux K, et al. Contemporary management of diabetic retinopathy in Canada: from guidelines to algorithm guidance. Ophthalmologica. 2014;231(1):2-15. doi:10.1159/000354548

6.         Mohamed Q, Gillies MC, Wong TY. Management of diabetic retinopathy: a systematic review. JAMA. 2007;298(8):902-916. doi:10.1001/jama.298.8.902

7.         Wang LZ, Cheung CY, Tapp RJ, et al. Availability and variability in guidelines on diabetic retinopathy screening in Asian countries. Br J Ophthalmol. 2017;101(10):1352-1360. doi:10.1136/bjophthalmol-2016-310002

8.         Gibson DM. Estimates of the Percentage of US Adults With Diabetes Who Could Be Screened for Diabetic Retinopathy in Primary Care Settings. JAMA Ophthalmol. 2019;137(4):440-444. doi:10.1001/jamaophthalmol.2018.6909

9.         Increase the proportion of adults with diabetes who have a yearly eye exam — D‑04 - Healthy People 2030 | health.gov. Accessed January 21, 2022. https://health.gov/healthypeople/objectives-and-data/browse-objectives/diabetes/increase-proportion-adults-diabetes-who-have-yearly-eye-exam-d-04

10.       Tran EMT, Bhattacharya J, Pershing S. Self-reported Receipt of Dilated Fundus Examinations Among Patients With Diabetes: Medicare Expenditure Panel Survey, 2002-2013. Am J Ophthalmol. 2017;179:18-24. doi:10.1016/j.ajo.2017.04.009

11.       Eppley SE, Mansberger SL, Ramanathan S, Lowry EA. Characteristics Associated with Adherence to Annual Dilated Eye Examinations among US Patients with Diagnosed Diabetes. Ophthalmology. 2019;126(11):1492-1499. doi:10.1016/j.ophtha.2019.05.033

12.       Fathy C, Patel S, Sternberg P, Kohanim S. Disparities in Adherence to Screening Guidelines for Diabetic Retinopathy in the United States: A Comprehensive Review and Guide for Future Directions. Semin Ophthalmol. 2016;31(4):364-377. doi:10.3109/08820538.2016.1154170

13.       Gibson DM. Eye care availability and access among individuals with diabetes, diabetic retinopathy, or age-related macular degeneration. JAMA Ophthalmol. 2014;132(4):471-477. doi:10.1001/jamaophthalmol.2013.7682

14.       Lovshin JA, Shah BR. Inadequate screening for retinopathy among recent immigrants with type 2 diabetes despite universal health care: A population-based study. J Diabetes Complications. 2017;31(4):664-668. doi:10.1016/j.jdiacomp.2016.12.011

15.       French DD, Behrens JJ, Jackson KL, et al. Payment Reform Needed to Address Health Disparities of Undiagnosed Diabetic Retinopathy in the City of Chicago. Ophthalmol Ther. 2017;6(1):123-131. doi:10.1007/s40123-016-0072-4

16.       Lim A, Stewart J, Chui TY, et al. Prevalence and risk factors of diabetic retinopathy in a multi-racial underserved population. Ophthalmic Epidemiol. 2008;15(6):402-409. doi:10.1080/09286580802435179

17.       Shi Q, Zhao Y, Fonseca V, Krousel-Wood M, Shi L. Racial disparity of eye examinations among the U.S. working-age population with diabetes: 2002-2009. Diabetes Care. 2014;37(5):1321-1328. doi:10.2337/dc13-1038

18.       Hale NL, Bennett KJ, Probst JC. Diabetes care and outcomes: disparities across rural America. J Community Health. 2010;35(4):365-374. doi:10.1007/s10900-010-9259-0

19.       Zhang X, Cotch MF, Ryskulova A, et al. Vision health disparities in the United States by race/ethnicity, education, and economic status: findings from two nationally representative surveys. Am J Ophthalmol. 2012;154(6 Suppl):S53-62.e1. doi:10.1016/j.ajo.2011.08.045

20.       Nwanyanwu KMJH, Nunez-Smith M, Gardner TW, Desai MM. Awareness of Diabetic Retinopathy: Insight From the National Health and Nutrition Examination Survey. Am J Prev Med. 2021;61(6):900-909. doi:10.1016/j.amepre.2021.05.018

21.       Lundeen EA, Wittenborn J, Benoit SR, Saaddine J. Disparities in Receipt of Eye Exams Among Medicare Part B Fee-for-Service Beneficiaries with Diabetes — United States, 2017. MMWR Morb Mortal Wkly Rep. 2019;68(45):1020-1023. doi:10.15585/mmwr.mm6845a3

22.       Yusuf R, Chen EM, Nwanyanwu K, Richards B. Neighborhood Deprivation and Adherence to Initial Diabetic Retinopathy Screening. Ophthalmol Retina. 2020;4(5):550-552. doi:10.1016/j.oret.2020.01.016

23.       Elam AR, Lee PP. Barriers to and Suggestions on Improving Utilization of Eye Care in High-Risk Individuals: Focus Group Results. Int Sch Res Notices. 2014;2014:527831. doi:10.1155/2014/527831

24.       Reduce vision loss from diabetic retinopathy — V‑04 - Healthy People 2030 | health.gov. Accessed January 21, 2022. https://health.gov/healthypeople/objectives-and-data/browse-objectives/sensory-or-communication-disorders/reduce-vision-loss-diabetic-retinopathy-v-04

25.       Resnikoff S, Felch W, Gauthier TM, Spivey B. The number of ophthalmologists in practice and training worldwide: a growing gap despite more than 200,000 practitioners. Br J Ophthalmol. 2012;96(6):783-787. doi:10.1136/bjophthalmol-2011-301378

26.       Das T, Takkar B, Sivaprasad S, et al. Recently updated global diabetic retinopathy screening guidelines: commonalities, differences, and future possibilities. Eye. 2021;35(10):2685-2698. doi:10.1038/s41433-021-01572-4

27.       Avidor D, Loewenstein A, Waisbourd M, Nutman A. Cost-effectiveness of diabetic retinopathy screening programs using telemedicine: a systematic review. Cost Eff Resour Alloc. 2020;18:16. doi:10.1186/s12962-020-00211-1

28.       Khan T, Bertram MY, Jina R, Mash B, Levitt N, Hofman K. Preventing diabetes blindness: cost effectiveness of a screening programme using digital non-mydriatic fundus photography for diabetic retinopathy in a primary health care setting in South Africa. Diabetes Res Clin Pract. 2013;101(2):170-176. doi:10.1016/j.diabres.2013.05.006

29.       Sharma M, Chakrabarty AS, Pavan R, Sharma R, Pratibha G. An integrated, mobile service for diabetic retinopathy in rural India. Community Eye Health. 2011;24(75):17-18.

30.       Ting DSW, Cheung GCM, Wong TY. Diabetic retinopathy: global prevalence, major risk factors, screening practices and public health challenges: a review. Clin Exp Ophthalmol. 2016;44(4):260-277. doi:10.1111/ceo.12696

31.       Chasan JE, Delaune B, Maa AY, Lynch MG. Effect of a Teleretinal Screening Program on Eye Care Use and Resources. JAMA Ophthalmology. 2014;132(9):1045-1051. doi:10.1001/jamaophthalmol.2014.1051

32.       Cheng YJ, Kanaya AM, Araneta MRG, et al. Prevalence of Diabetes by Race and Ethnicity in the United States, 2011-2016. JAMA. 2019;322(24):2389-2398. doi:10.1001/jama.2019.19365

33.       Nørgaard MF, Grauslund J. Automated Screening for Diabetic Retinopathy - A Systematic Review. Ophthalmic Res. 2018;60(1):9-17. doi:10.1159/000486284

34.       van der Heijden AA, Nijpels G, Badloe F, et al. Prediction models for development of retinopathy in people with type 2 diabetes: systematic review and external validation in a Dutch primary care setting. Diabetologia. 2020;63(6):1110-1119. doi:10.1007/s00125-020-05134-3

35.       Emamipour S, van der Heijden AAWA, Nijpels G, et al. A personalised screening strategy for diabetic retinopathy: a cost-effectiveness perspective. Diabetologia. 2020;63(11):2452-2461. doi:10.1007/s00125-020-05239-9

36.       Grzybowski A, Brona P, Lim G, et al. Artificial intelligence for diabetic retinopathy screening: a review. Eye (Lond). 2020;34(3):451-460. doi:10.1038/s41433-019-0566-0

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