The prevalence of diabetes among adults globally has increased from 108 million in 1980 to 537 million in 2021.
[ 1 , 2 ] The incidence of type 2 diabetes mellitus (T2DM) has more than doubled over the past three decades, particularly in developing countries, which has given impetus to this drastic increase in diabetes. [ 3 ] In 2019, India had an estimated 77 million individuals with diabetes mellitus, making it the second highest country globally. [ 4 ] While the manifestations of T2DM are legion, an important ocular manifestation is diabetic retinopathy (DR). DR can lead to vision loss as well as retinal detachment, preretinal or vitreous hemorrhage, or macular edema through a variety of mechanisms. [ 5 ]
Many observational studies and clinical trials have identified that interventions related to glycemic and blood pressure control are helpful in the management of DR.
[ 6 ] However, another invention that is paramount in the management of DR is counseling that can improve patient knowledge and attitudes. Decreased knowledge is associated with decreased attendance to preemptive vision screenings. A recent study that was conducted in a tertiary care hospital in Mumbai found that 63% of T2DM participants knew that diabetes could affect the retina and would only attend a dilated fundus examination if they begin to experience vision changes. [ 7 ]
On the other hand, having heightened knowledge is associated with attendance to screenings, which can lead to earlier detection of DR and more timely treatment before DR progresses to permanent vision loss.
[ 8 , 9 ] In fact, patient education regarding DR can significantly increase compliance to follow-up screenings. [ 10 ] Earlier detection and treatment are paramount because neural retinal damage and hard-to-detect microvascular changes can occur during the asymptomatic phase of DR. [ 11 ] Thus, interventions that specifically target patient knowledge may be a promising avenue in helping to alleviate the burden of avoidable blindness caused by DR.
Baseline knowledge and attitudes regarding DR of T2DM individuals from the slums of Mumbai, such as Dharavi, to the best of our knowledge, have not been previously reported. Furthermore, while previous studies have been conducted in areas such as Egypt to investigate the impacts of educational programs on patient knowledge regarding DR, to date, pre- and post-intervention surveys assessing DR knowledge and attitudes in the slums of Mumbai have not been conducted.
[ 10 , 12 ] While there have been previous studies assessing knowledge and awareness regarding DR among T2DM individuals in other regions of India, the reported knowledge and awareness vary widely across studies. [ 13 , 14 ] Therefore, we sought to discern the knowledge and awareness of T2DM individuals from Dharavi, a region not previously studied and one that has a diverse population with many different ethnicities.
In our pre- and post-intervention survey study, we firstly fill a gap in the literature by assessing baseline knowledge and attitudes regarding DR of T2DM individuals from Dharavi, one of the largest slums in Mumbai, as part of our pre-intervention survey. Unfortunately, many survey studies that assess knowledge and/or attitudes are cross sectional and do not take any additional measures to rectify any knowledge that may be lacking. However, in our study, we then went on to provide individual DR counseling sessions to each of the study participants and then assessed their changes in knowledge and attitudes after with our post-intervention survey. We have previously reported on the prevalence of T2DM and DR as well as risk factors in the slums of Mumbai in western India, as part of our Aditya Jyot Diabetic Retinopathy in Urban Mumbai Slums Study.
[ 15 , 16 ] In our third report, we describe our findings regarding the impacts and efficacy of individual education sessions on the knowledge and attitudes of T2DM individuals regarding DR. Methods
The overall study design and methodology is described in our two previous reports.
[ 15 , 16 ] The study design and interventions relevant to this report took place over two phases. The two stages were as follows: (1) pre-camp and (2) camp. [ 15 ]
During the pre-camp phase, numerous social and community workers were recruited and trained before enrolling potential study subjects (>30 years old) from the general population in Dharavi, one of the largest slums in Mumbai. Recruiters visited houses door to door and inquired potential participants about their willingness to participate in the study, answering any of their questions. Recruiters gave the consenting subjects further information regarding follow-up for the next part of the study, the camp phase.
During the Camp phase, a screening for T2DM was performed, measuring fasting blood glucose levels with a glucometer.
[ 15 ] Subjects were then categorized as provisional diabetic (PD), known diabetic (KD), or not-known diabetic (NKD), as defined in our previous reports. [ 15 , 17–19 ] Those who were categorized as KD or PD were each registered for an individual counseling session.
Before the counseling session, community health workers assessed the baseline knowledge and attitudes of each subject before their assigned individual counseling session using an adapted questionnaire from the Sankara Nethralaya Diabetic Retinopathy Epidemiology and Molecular Genetic Study.
[ 17 ] The questionnaire was available in Marathi, English, and Hindi. The questionnaire consisted of two sections: the first part assessed knowledge regarding T2DM and DR (eight questions), while the second part assessed attitudes regarding DR (four questions).
During the counseling session, the study participant was counseled using a flip chart and various eye models regarding the signs, symptoms, and manifestations of DR in the setting of T2DM. The community health workers also emphasized the importance of early detection of DR, attending screenings, various preventative measures, and the impacts of lifestyle habits on the development of DR. The counseling sessions lasted about 15 min. Immediately after the counseling sessions, the subjects were screened for DR using a binocular indirect ophthalmoscope. After this, the subjects were immediately given the same survey to assess any potential improvements in knowledge and attitudes.
For each of the eight questions assessing knowledge, a score of 0 was rewarded for wrong responses and a score of 1 was rewarded for correct answers. An individual was categorized as having “good knowledge” if at least seven out of eight questions assessing knowledge were answered correctly. If less than seven questions were answered correctly, the individual was categorized as having “poor knowledge.” Differences in knowledge changes based on gender, age, duration of diabetes mellitus, and presence of DR were also evaluated.
The research team obtained approval from the Institutional Review Board and adhered to the tenets of the Declaration of Helsinki.
The collected data was downloaded without identifiers to a format compatible with statistical software (SPSS for Windows version 13.0; SPSS Inc., Chicago, IL, USA) for further data analysis. Descriptive statistics were performed on each study variable. Continuous variables were reported using a mean or median as appropriate. Categorical variables, including patient demographics, were reported as frequencies and percent occurrence.
Paired statistical analysis for pre- and post-responses with dichotomous categorical outcomes (yes or no) was performed with McNemar Chi-square testing. Pre- and post-survey responses for questions that had more than two answer choices were paired using a McNemar Bowker Test.
P values of less than 0.05 were considered statistically significant. Results
Study participant characteristics
A total of 1718 participant survey responses were collected before and after the counseling sessions throughout the duration of the study.
Table 1 outlines the characteristics of the 1718 study participants. Of these, 54.2% (931/1718) were female and 45.8% (787/1718) were male. The average age of the study participants was 55.17 ± 10.25 years; 48.5% (833/1718) had T2DM between 1 and 5 years, while 37.6% (646/1718) had T2DM for at least 5 years. Also, 76.7% (1317/1718) of participants did not have DR, while 17.4% (299/1718) were screened positive for DR. Table 1:
Study participants’ baseline characteristics
Before the session, we also inquired about relevant past ocular history and management. Responses showed that 70.5% (1212/1718) of subjects had experienced vision changes in the past 10 years and 93.0% (1598/1718) had experienced eye problems in the past. Of these participants with past eye problems, the most reported symptoms were eye pain (30.0%, 515/1718), headache (26.4%, 454/1718), and watering of the eyes (14.4%, 247/1718). Only 55.5% (953/1718) of subjects had consulted ophthalmologists for these eye problems and 8.4% (144/1718) had their retina examined.
Counseling sessions improved participants’ knowledge regarding DR
Table 2 comprehensively outlines the changes in participants’ knowledge regarding T2DM and DR. We used McNemar Chi-square or McNemar Bowker testing to assess statistically significant changes in knowledge regarding diabetes mellitus and DR, and we found that overall, the participants showed statistically significant improvements in knowledge across all questions (all P < 0.0001, except for question 1). More subjects responded that diabetes can affect the eye (from 30.8%, 530/1718 to 90.4%, 1553/1718). More subjects understood after the counseling session that properly managing blood sugar levels is paramount in trying to prevent the onset of DR (from 30.6%, 526/1718 to 83.5%, 1434/1718). Participants showed a greater understanding that an eye examination should be conducted as soon as possible after the diagnosis of diabetes (from 17.1%, 294/1718 to 93.2%, 1602/1718). Subjects learned that DR could lead to severe vision loss (from 17.6%, 303/1718 to 94.3%, 1620). After the counseling session, more subjects were aware of how a retinal examination is conducted. Subjects were also more aware of the pathognomonic findings in DR, with more participants likely to respond that DR can lead to neovascularization (from 7.2% to 49.8%), macular edema (9.5% to 35.5%), and retinal detachment (1.7% to 5.8%). Many subjects also learned that vision loss due to diabetes is treatable (from 16.1%, 276/1718 to 92.3%, 1585/1718). Table 2:
Participants’ knowledge improved significantly after individual counseling
Attitudes regarding DR changed after the counseling sessions
Table 3 summarizes the changes in subjects’ attitudes regarding DR. A significantly greater number of subjects expressed a greater willingness to attend eye examinations at a frequency that is in accordance with best practices. After the counseling session, a greater number of subjects expressed that they would prefer care from an ophthalmologist in the event of DR (from 4.3%, 74/1718 to 16.6%, 286/1718). In addition, after the counseling sessions, more subjects preferred laser treatment for DR (from 4.9%, 85/1718 to 75.8%, 1303/1718). Responses also showed that a greater number of subjects learned that attending an eye examination can be helpful in “getting rid of ocular symptoms associated with DR” (from 15.9%, 274/1718 to 50.8%, 872/1718). Table 3:
Participants’ attitudes improved significantly after individual counseling
Changes in knowledge did not depend on gender, age, duration, or presence of DR
All individuals were categorized as either having “good knowledge” or “poor knowledge” depending on the number of questions assessing knowledge that were answered correctly. Before the counseling sessions, most individuals demonstrated poor knowledge regardless of gender, age, duration of T2DM, and presence of DR [
Table 4]. A total of 1057 individuals who were scored as having poor knowledge before the session demonstrated good knowledge after the counseling intervention. Improvements in knowledge after the counseling session were seen regardless of gender, age, duration of T2DM, and presence of DR (all P < 0.001). Table 4:
Stratified analysis of changes in knowledge
The primary objective of this study was to describe the impacts of individual DR counseling sessions on T2DM individuals from Dharavi, specifically their knowledge and attitudes regarding DR. Surveys were administered to T2DM participants, who were enrolled prospectively, before and after the counseling session to assess improvements in patient knowledge and changes in awareness. We observed significant improvements in participant knowledge and attitudes post-counseling, with a significantly greater number of subjects after the counseling session demonstrating willingness to attend an eye exam for DR (
P < 0.0001).
The American Academy of Ophthalmology recommends an eye examination at the time of diagnosis and then yearly vision screenings thereafter for T2DM patients.
[ 20 ] It has been shown that lesser patient knowledge and awareness and lack of access to education programs are associated with nonadherence to vision care guidelines among diabetics. [ 21 , 22 ] In addition, lack of awareness and knowledge among patients can also lead to an increased likelihood that their referral gets delayed or that they present with advanced DR on eye examination. [ 23 , 24 ] In our study, we found that out of the 299 T2DM participants who were newly diagnosed with DR through our screening, almost all of them had poor knowledge (98%, 293/299).
Previous exposure to diabetes education classes and improved awareness are associated with obtaining proper eye-related care as well as attending a dilated eye examination.
[ 25 , 26 ] In our study, a significantly greater number of participants demonstrated a newfound willingness to attend an eye exam after the counseling intervention. In addition, a study conducted by Schoenfeld et al. [ 21 ] found that patients who are nonadherent to vision screening guidelines are more likely to believe that treatments for DR do not exist. Our study found that there was a significant increase in those who were aware that DR is treatable (from 16.1% to 92.3%).
Targeting patient awareness and knowledge via education interventions seems to be paramount, given that a significant proportion of diabetes patients are not compliant with recommended guidelines for the management of DR and that compliance is strongly associated with education levels and knowledge.
[ 27–33 ] In fact, those in lower-income brackets tend to have less knowledge regarding DR. [ 34 , 35 ] Our study recruited T2DM mellitus participants from Dharavi, a slum in Mumbai where residents have an average individual monthly income of 5000 rupees (approximately 67 US dollars). [ 36 ] Consistent with these reports regarding lower-income diabetics, we found that before the education interventions, our study participants demonstrated low baseline awareness. For example, a staggering 54.2% of participants did not know the recommended frequency to attend vision screenings and 69.2% of participants did not know that diabetes can affect the eye. Therefore, as evident in our study, strategic targeting of those with lesser awareness, especially those living in lower-income areas such as Dharavi, can yield drastic improvements in knowledge and awareness.
Awareness and attendance to eye examinations are paramount because they ensure early detection and thus more timely treatment of DR, potentially reducing significant loss of vision by up to 94%.
[ 21 , 37 , 38 ] A study conducted by Agardh et al. [ 39 ] found that introducing a screening system for the early detection of treatable retinopathy can reduce the risk of permanent vision loss and blindness significantly in T2DM patients. DR is, in fact, most treatable during its early, asymptomatic stage. [ 21 ] Hard-to-detect neural damage can even occur in DR patients before the onset of microvascular abnormalities. [ 11 ]
There have been previous cross-sectional studies assessing baseline awareness of diabetes patients via questionnaires. However, there have been no studies assessing baseline awareness of DR in Dharavi. Furthermore, there are fewer pre- and post-intervention studies reporting the impacts of specific educational interventions on patient knowledge and attitudes regarding DR. Rani
et al. [ 40 ] conducted a study that promoted awareness regarding DR among the general population through awareness meetings, visual aids, media, and celebrations and special events. Another study conducted by Umaefulam and Premkumar [ 41 ] assessed the effects of mobile health education on DR awareness among indigenous women, and consistent with this report, our study also found significant improvements in knowledge. Although it is difficult to compare these studies due to differences in interventions and populations, trends can still be meaningfully compared. Ultimately, consistent with these studies, we also observed improvements in knowledge and attitudes regarding DR after the educational interventions.
There were limitations to this study. As the re-evaluation was done right after the counseling session, it is difficult to assess if the gained knowledge and improved attitudes seen in our study participants led to changes in practices and concomitant improvements in DR-related clinical outcomes. In addition, it is difficult to assess if the knowledge gained and improved attitudes were as robust in the long term. However, given that there was such a robust improvement in knowledge and attitudes and that there are many studies in the literature that have shown a significant association between knowledge and practice, we believe that the impacts of our endeavors are certainly not nonsignificant. Furthermore, while there are strengths to administering surveys versus a self-administered survey (i.e., higher response rate, clarification of ambiguous items is possible), there are limitations to administering surveys, such as lesser reliability and interviewer bias.
[ 42 ] Conclusion
Baseline knowledge and attitudes among T2DM individuals from one of the largest slums in Mumbai, Dharavi, are low, and educational interventions specifically targeting these low-income populations can have significant impacts. This study highlights the need for more targeted educational interventions for low-income T2DM individuals in areas such as Dharavi, especially since up to 17.4% (299/1718) of our T2DM participants had DR and low baseline knowledge. Given the projected increase in the rates of T2DM and DR in India, educational interventions like the one described herein may be a useful tool in dampening the deleterious effects caused by this looming public health problem.
Financial support and sponsorship
The project is funded by the World Diabetes Foundation (WDF08-338).
Conflicts of interest
There are no conflicts of interest.
1. NCD Risk Factor Collaboration (NCD-RisC). Worldwide trends in diabetes since 1980:A pooled analysis of 751 population-based studies with 4·4 million participants Lancet 2016;387:1513–30.
2. Facts & figures. Available from:
. [Last accessed on 2022 Oct 16].
3. Chen L, Magliano DJ, Zimmet PZ. The worldwide epidemiology of
type 2 diabetes mellitus
—present and future perspectives Nat Rev Endocrinol 2012;8:228–36.
4. Saeedi P, Petersohn I, Salpea P, Malanda B, Karuranga S, Unwin N, et al. Global and regional diabetes prevalence estimates for 2019 and projections for 2030 and 2045:Results from the International Diabetes Federation Diabetes Atlas, 9
edition Diabetes Res Clin Pract 2019;157:107843.
5. Zhang X, Saaddine JB, Chou CF, Cotch MF, Cheng YJ, Geiss LS, et al. Prevalence of diabetic retinopathy in the United States, 2005-2008 JAMA 2010;304:649.
6. Kobrin Klein BE. Overview of epidemiologic studies of diabetic retinopathy Ophthalmic Epidemiol 2007;14:179–83.
7. Shah K, Gandhi A, Natarajan S. Diabetic retinopathy awareness and associations with multiple comorbidities:Insights from DIAMOND Study Indian J Endocrinol Metab 2018;22:30–5.
8. Lian J, McGhee SM, Gangwani RA, Lam CLK, Yap MKH, Wong DSH. Awareness of diabetic retinopathy and its association with attendance for systematic screening at the public primary care setting:a cross-sectional study in Hong Kong BMJ Open 2018;8:e019989. doi:10.1136/bmjopen-2017-019989.
9. Misra A, Bachmann MO, Greenwood RH, Jenkins C, Shaw A, Barakat O, et al. Trends in yield and effects of screening intervals during 17 years of a large UK community-based diabetic retinopathy screening programme Diabet Med 2009;26:1040–7.
10. Moinul P, Barbosa J, Qian J, Chen ML, Mohaghegh M, Kaur H, et al. Does patient education improve compliance to routine diabetic retinopathy screening? J Telemed Telecare 2020;26:161–73.
11. Safi H, Safi S, Hafezi-Moghadam A, Ahmadieh H. Early detection of diabetic retinopathy Surv Ophthalmol 2018;63:601–8.
12. Khalaf FR, Fahmy HM, Ibrahim AK, Mohamed GA, El Sayed Ez Eldeen M, Elkady A, et al. Does a diabetic retinopathy educational program raise awareness among elderly diabetic patients? Diabetes Metab Syndr Obes 2019;12:1867–75.
13. Hussain R, Rajesh B, Giridhar A, Gopalakrishnan M, Sadasivan S, James J, et al. Knowledge and awareness about diabetes mellitus and diabetic retinopathy in suburban population of a South Indian state and its practice among the patients with diabetes mellitus:A population-based study Indian J Ophthalmol 2016;64:272–6.
14. Venugopal D, Lal B, Fernandes S, Gavde D. Awareness and knowledge of diabetic retinopathy and associated factors in Goa:A hospital-based cross-sectional study Indian J Ophthalmol 2020;68:383–90.
15. Sunita M, Desai S, Vinay P, Moolani S, Rai N, Deepen S, et al. Aditya Jyot-diabetic retinopathy in urban Mumbai Slums Study (AJ-DRUMSS):Study Design and methodology –report 1 Ophthalmic Epidemiol 2014;21:51–60.
16. Sunita M, Singh AK, Rogye A, Sonawane M, Gaonkar R, Srinivasan R, et al. Prevalence of diabetic retinopathy in urban slums:The Aditya Jyot Diabetic Retinopathy in urban Mumbai slums study—report 2 Ophthalmic Epidemiol 2017;24:303–10.
17. Agarwal S, Raman R, Paul PG, Rani PK, Uthra S, Gayathree R, et al. Sankara Nethralaya—Diabetic Retinopathy Epidemiology and Molecular Genetic Study (SN—DREAMS 1):Study design and research methodology Ophthalmic Epidemiol 2005;12:143–53.
18. American Diabetes Association. Standards of medical care in diabetes – 2012. Diabetes Care 2012;35 (Suppl 1):S11–63.
19. Eeg-Olofsson K, Cederholm J, Nilsson PM, Gudbjörnsdóttir S, Eliasson B Steering Committee of the Swedish National Diabetes Register. Glycemic and risk factor control in type 1 diabetes:Results from 13,612 patients in a national diabetes register Diabetes Care 2007;30:496–502.
20. Chuck RS, Dunn SP, Flaxel CJ, Gedde SJ, Mah FS, Miller KM, et al. Comprehensive adult medical eye evaluation preferred practice pattern® Ophthalmology 2021;128:P1–29. doi: 10.1016/j.ophtha. 2020.10.024.
21. Schoenfeld ER, Greene JM, Wu SY, Leske MC. Patterns of adherence to diabetes vision care guidelines Ophthalmology 2001;108:563–71.
22. Dervan E, Lillis D, Flynn L, Staines A, O'Shea D. Factors that influence the patient uptake of diabetic retinopathy screening Ir J Med Sci 2008;177:303–8.
23. Muecke JS, Newland HS, Ryan P, Ramsay E, Aung M, Myint S, et al. Awareness of diabetic eye disease among general practitioners and diabetic patients in Yangon, Myanmar Clin Exp Ophthalmol 2008;36:265–73.
24. Alzahrani SH, Bakarman MA, Alqahtani SM, Alqahtani MS, Butt NS, Salawati EM, et al. Awareness of diabetic retinopathy among people with diabetes in Jeddah, Saudi Arabia Ther Adv Endocrinol Metab 2018;9:103–12.
25. Brechner RJ. Ophthalmic examination among adults with diagnosed diabetes mellitus JAMA J Am Med Assoc 1993;270:1714.
26. Will JC, German RR, Schuman E, Michael S, Kurth DM, Deeb L. Patient adherence to guidelines for diabetes eye care:Results from the diabetic eye disease follow-up study Am J Public Health 1994;84:1669–71.
27. Kupfer C. The challenge of transferring research results into patient care Ophthalmology 1989;96:737–8.
28. Smith RE, Patz A. Diabetes 2000—Closing the gap Ophthalmology 1990;97:153–4.
29. Taylor HR. Diabetic retinopathy:A public health challenge Am J Ophthalmol 1997;123:543–5.
30. Moss SE. Factors associated with having eye examinations in persons with diabetes Arch Fam Med 1995;4:529–34.
31. Legorreta AP, Hasan MM, Peters AL, Pelletier KR, Leung KM. An intervention for enhancing compliance with screening recommendations for diabetic retinopathy:A bicoastal experience Diabetes Care 1997;20:520–3.
32. Orr P, Barrón Y, Schein OD, Rubin GS, West SK. Eye care utilization by older Americans Ophthalmology 1999;106:904–9.
33. Mukamel BD, Bresnick HG, Wang Q, Dickey FC. Barriers to compliance with screening guidelines for diabetic retinopathy Ophthalmic Epidemiol 1999;6:61–72.
34. Seneviratne B, Prathapan S. Knowledge on diabetic retinopathy among diabetes mellitus patients attending the Colombo South Teaching Hospital, Sri Lanka J US-China Med Sci 2016;13:35–46.
35. Rani P, Raman R, Subramani S, Perumal G, Kumaramanickavel G, Sharma T. Knowledge of diabetes and diabetic retinopathy among rural populations in India, and the influence of knowledge of diabetic retinopathy on attitude and practice Rural Remote Health 2008;8:838.
36. Dharavi slum area in mumbai | COVID-19 case count rises in Dharavi: What do we know about Asia's largest slum area? | India News. Available from:
. [Last accessed on 2022 Oct 16].
37. Photocoagulation treatment of proliferative diabetic retinopathy. Clinical application of Diabetic Retinopathy Study (DRS) findings, DRS Report Number 8 The Diabetic Retinopathy Study Research Group. Ophthalmology 1981;88:583–600.
38. . Photocoagulation for diabetic macular edema:Early treatment diabetic retinopathy study report number 1 early treatment diabetic retinopathy study research group. Arch Ophthalmol 1985;103:1796–806.
39. Agardh E, Agardh CD, Hansson-Lundblad C. The five-year incidence of blindness after introducing a screening programme for early detection of treatable diabetic retinopathy Diabet Med 1993;10:555–9.
40. Rani PK, Raman R, Agarwal S, Paul PG, Uthra S, Margabandhu G, et al. Diabetic retinopathy screening model for rural population:Awareness and screening methodology Rural Remote Health 2005;5:350.
41. Umaefulam V, Premkumar K. Impact of mobile health in diabetic retinopathy awareness and eye care behavior among Indigenous women Mhealth 2020;6:14.
42. Administered Questionnaire-an overview | ScienceDirect Topics. Available from:
. [Last accessed on 2022 Oct 17].