Diabetes mellitus is one of the most common non-communicable diseases in the world today, and India, often referred to as the diabetes capital of the world, carries a huge burden of this disease. According to the International Diabetes Federation, the number of adults living with diabetes worldwide has crossed 500 million, and a large proportion of them reside in South Asian countries, including India1. Chronic hyperglycaemia associated with diabetes mellitus leads to widespread microvascular and macrovascular complications affecting almost every organ system of the body, and the eye is no exception2. While diabetic retinopathy, cataract and glaucoma are well studied ocular complications of diabetes, dry eye disease has received comparatively less clinical attention, despite being one of the commonest causes of ocular discomfort in diabetic patients3. Dry eye disease is a multifactorial disorder of the tear film and ocular surface that results in symptoms of discomfort, visual disturbance and tear film instability, with potential damage to the ocular surface. In diabetic patients, dry eye occurs due to autonomic neuropathy affecting the lacrimal gland, reduced corneal sensitivity from sensory neuropathy, goblet cell dysfunction and alteration in tear film composition4. Several studies conducted in different parts of India and abroad have reported a wide range of prevalence of dry eye disease among diabetics, varying from about 20 per cent to over 70 per cent, depending upon the diagnostic criteria used, duration of diabetes and the population studied5. Jharkhand, being a state with a large rural and semi-urban population having limited access to comprehensive eye care services, is likely to have a considerable but poorly documented burden of diabetic dry eye disease. Many patients remain asymptomatic in the early stages or attribute their symptoms to ageing or other causes, resulting in delayed diagnosis and treatment6. Early identification of dry eye disease in diabetic patients is important because untreated dry eye can lead to punctate epithelial erosions, corneal ulceration, secondary infection and, in severe cases, visual impairment. Furthermore, dry eye can complicate cataract and other ocular surgeries commonly required by diabetic patients, and can adversely affect their quality of life7. Considering the limited local data from Jharkhand and the clinical importance of early detection, the present study was undertaken to assess the prevalence, severity and associated risk factors of dry eye disease among patients with diabetes mellitus attending the tertiary care hospital8. Objectives 1. To determine the prevalence of dry eye disease among patients with diabetes mellitus attending the outpatient department of a tertiary care hospital of Jharkhand. 2. To study the distribution of dry eye disease according to gender and duration of diabetes mellitus. 3. To assess the severity of dry eye disease among diabetic subjects using standard clinical tests. 4. To identify the risk factors associated with dry eye disease in diabetic patients and to calculate their odds ratio.

Study Design and Setting This was a hospital-based, cross-sectional, observational study conducted in the Department of Physiology, Department of Ophthalmology, in collaboration with the Department of General Medicine, of a tertiary care hospital of Jharkhand, over a period of six months. Patients attending the diabetic and ophthalmology outpatient departments were screened for eligibility. Study Population The study population consisted of adult patients of either gender, above 18 years of age, who had a confirmed diagnosis of type 1 or type 2 diabetes mellitus as per American Diabetes Association criteria, and who attended the outpatient department during the study period. Sample Size Calculation The sample size for this study was calculated using the standard formula for estimating a single population proportion, applicable to cross-sectional prevalence studies: n = Z² × p × (1 − p) / d² Where, n = required minimum sample size Z = standard normal deviate at 95 per cent confidence level = 1.96 p = expected prevalence of dry eye disease among diabetics, taken as 54 per cent (0.54), based on the prevalence reported by Manaviat et al. in a similar hospital-based study q = (1 − p) = 0.46 d = allowable margin of error, taken as 10.7 per cent (0.107) Substituting the values in the formula: n = (1.96) ² × 0.54 × 0.46 / (0.107) ² n = 3.8416 × 0.2484 / 0.01145 n ≈ 83.4, rounded off to 84 Hence, a final sample size of 84 diabetic patients was taken for the present study. Sampling Method A non-probability consecutive sampling technique was used, wherein every diabetic patient attending the outpatient department during the study period and satisfying the eligibility criteria was enrolled successively until the calculated sample size of 84 was achieved. This method was chosen as it is simple, practical and reduces selection bias by including all eligible consecutive attendees rather than a chosen few. Inclusion Criteria 1. Patients diagnosed with type 1 or type 2 diabetes mellitus of any duration. 2. Age above 18 years, of either gender, willing to give informed written consent. 3. Patients able to co-operate for ocular examination and tear film tests. Exclusion Criteria 1. Patients with a history of ocular surgery, trauma or contact lens use in the preceding six months. 2. Patients with pre-existing ocular surface disease unrelated to diabetes, such as Sjögren's syndrome, Stevens-Johnson syndrome, or vitamin A deficiency. 3. Patients on medications known to cause dry eye, such as antihistamines, anticholinergics or systemic retinoids, apart from diabetes-related medication. 4. Pregnant and lactating women. Methods of Data Collection After obtaining informed written consent and clearance from the Institutional Ethics Committee, a pre-designed and pre-tested proforma was used to record demographic details, duration of diabetes, glycaemic status (HbA1c), presence of diabetic retinopathy, neuropathy and other systemic co-morbidities. Every subject underwent a comprehensive ocular examination, and dry eye disease was diagnosed and graded using the following standard tests: • Ocular Surface Disease Index (OSDI) questionnaire, for subjective symptom scoring. • Tear film break-up time (TBUT), measured with fluorescein dye under cobalt blue light; a value of less than 10 seconds was taken as abnormal. • Schirmer's test (without anaesthesia), with a value of less than 10 mm in 5 minutes being considered abnormal. A diagnosis of dry eye disease was made when the patient had symptoms on OSDI together with an abnormal TBUT and/or Schirmer's test. Severity was graded as mild, moderate or severe on the basis of a combination of symptom score and objective test values, following the Dry Eye WorkShop (DEWS) severity grading scheme. Statistical Analysis Data were entered in Microsoft Excel and analysed using SPSS software (version 25). Descriptive statistics were expressed as frequency and percentage for categorical variables and as mean with standard deviation for continuous variables. Chi-square test was applied to test the association between dry eye disease and various categorical risk factors. Odds ratio with 95 per cent confidence interval was calculated for important risk factors. A p-value of less than 0.05 was considered statistically significant. Ethical Considerations The study was conducted after approval from the Institutional Ethics Committee of the hospital. Written informed consent was obtained from every participant prior to enrolment, and confidentiality of patient data was strictly maintained throughout the study, in accordance with the Declaration of Helsinki.

A total of 84 patients with diabetes mellitus were enrolled in the study and examined for dry eye disease. The findings are presented below under sociodemographic characteristics, duration of diabetes, gender-wise and duration-wise prevalence of dry eye, severity grading, risk factor analysis and clinical management. 4.1 Sociodemographic Profile of Study Subjects Table: Sociodemographic Distribution of Study Subjects (N = 84) Variable Category Number (n) Percentage (%) Age group (years) ≤ 40 8 9.5 41–50 18 21.4 51–60 30 35.7 > 60 28 33.3 Gender Male 46 54.8 Female 38 45.2 Residence Urban 50 59.5 Rural 34 40.5 Educational status Illiterate 12 14.3 Primary school 20 23.8 Secondary school 30 35.7 Graduate and above 22 26.2 Type of diabetes mellitus Type 1 6 7.1 Type 2 78 92.9 Body Mass Index (BMI) Normal (18.5–24.9) 30 35.7 Overweight (25–29.9) 34 40.5 Obese (≥ 30) 20 23.8 The majority of the study subjects (35.7 per cent) belonged to the 51–60 years age group, and males (54.8 per cent) slightly outnumbered females (45.2 per cent). Most patients were urban residents (59.5 per cent) and had type 2 diabetes mellitus (92.9 per cent). A considerable proportion of subjects were overweight or obese (64.3 per cent combined), reflecting the well-known association between obesity and type 2 diabetes. 4.2 Duration of Diabetes Mellitus Table 1: Distribution of Study Subjects Based on Duration of Diabetes (N = 84) Duration of Diabetes Number of Subjects (n) Percentage (%) Less than 5 years 24 28.6 5–10 years 30 35.7 More than 10 years 30 35.7 Total 84 100.0 Table 1 shows that a little over one-fourth of the subjects (28.6 per cent) had diabetes for less than 5 years, while the remaining 71.4 per cent had been diabetic for 5 years or more, indicating that most subjects attending the hospital had a moderately long-standing history of diabetes mellitus. 4.3 Prevalence of Dry Eye Based on Gender Table 2: Prevalence of Dry Eye among Diabetics Based on Gender (N = 84) Gender Total Diabetics Dry Eye Present, n (%) Dry Eye Absent, n (%) Male 46 28 (60.9%) 18 (39.1%) Female 38 26 (68.4%) 12 (31.6%) Total 84 54 (64.3%) 30 (35.7%) Chi-square value = 0.55, degrees of freedom = 1, p-value = 0.46 (not statistically significant). Out of the 84 diabetic subjects studied, dry eye disease was present in 54 (64.3 per cent), giving an overall prevalence of nearly two-thirds. The prevalence was somewhat higher in females (68.4 per cent) than in males (60.9 per cent); however, on applying the Chi-square test, this gender difference was not found to be statistically significant (p = 0.46), suggesting that both genders are almost equally vulnerable to dry eye disease once they develop diabetes mellitus. Of the total 54 dry eye positive cases, males contributed 28 cases (51.9 per cent) and females contributed 26 cases (48.1 per cent), as depicted in the pie chart above. Although the number of affected males was marginally higher in absolute terms, this reflects the slightly larger proportion of males in the overall study sample rather than a true gender-based predisposition, as is clear from the higher percentage prevalence within females shown in Table 2. 4.4 Prevalence of Dry Eye Based on Duration of Diabetes Table 3: Prevalence of Dry Eye Based on Duration of Diabetes (N = 84) Duration of Diabetes Total Subjects Dry Eye Present, n (%) Dry Eye Absent, n (%) Less than 5 years 24 10 (41.7%) 14 (58.3%) 5–10 years 30 20 (66.7%) 10 (33.3%) More than 10 years 30 24 (80.0%) 6 (20.0%) Total 84 54 (64.3%) 30 (35.7%) Chi-square value = 10.86, degrees of freedom = 2, p-value = 0.004 (statistically significant). Table 3 clearly demonstrates a rising trend in the prevalence of dry eye disease with increasing duration of diabetes mellitus, from 41.7 per cent in patients with less than 5 years of disease to 80.0 per cent in those with more than 10 years of disease. This association was found to be statistically significant (p = 0.004), confirming that duration of diabetes is an important determinant of dry eye disease, most likely through the cumulative effect of chronic hyperglycaemia on the lacrimal gland and corneal nerves. 4.5 Severity of Dry Eye among Diabetic Subjects Table 4: Severity of Dry Eye among Diabetic Subjects (n = 54) Severity Grade Number of Subjects (n) Percentage (%) Mild 24 44.4 Moderate 20 37.0 Severe 10 18.6 Total 54 100.0 Among the 54 subjects diagnosed with dry eye disease, the majority (44.4 per cent) had mild disease, 37.0 per cent had moderate disease and 18.6 per cent had severe disease. This pattern indicates that while most cases were of mild to moderate severity and potentially manageable with conservative measures, nearly one-fifth of the affected patients had severe disease requiring more intensive treatment and closer follow-up. 4.6 Risk Factors Associated with Dry Eye Disease Table 5: Risk Factors Associated with Dry Eye Disease among Diabetic Subjects Risk Factor Dry Eye Present (n=54), n (%) Dry Eye Absent (n=30), n (%) p-value Age > 60 years 22 (40.7%) 6 (20.0%) 0.048* Female gender 26 (48.1%) 12 (40.0%) 0.46 Duration of DM > 10 years 24 (44.4%) 6 (20.0%) 0.012* Poor glycaemic control (HbA1c ≥ 7%) 38 (70.4%) 12 (40.0%) 0.011* Presence of diabetic retinopathy 20 (37.0%) 4 (13.3%) 0.028* Presence of diabetic peripheral neuropathy 18 (33.3%) 5 (16.7%) 0.09 Co-existing hypertension 24 (44.4%) 10 (33.3%) 0.31 Smoking/tobacco use 12 (22.2%) 4 (13.3%) 0.32 *Statistically significant at p < 0.05. Table 5 summarises the various risk factors examined in relation to dry eye disease. Age above 60 years, duration of diabetes exceeding 10 years, poor glycaemic control indicated by HbA1c of 7 per cent or more, and the presence of diabetic retinopathy were found to be significantly associated with dry eye disease (p < 0.05 for each). On the other hand, female gender, diabetic peripheral neuropathy, co-existing hypertension and smoking, although more frequent among dry eye positive subjects, did not reach statistical significance in this sample, possibly owing to the relatively modest sample size. 4.7 Odds Ratio Analysis of Risk Factors To further quantify the strength of association between the significant risk factors and dry eye disease, odds ratio (OR) with 95 per cent confidence interval (CI) was calculated for each factor. An odds ratio greater than 1 indicates increased risk, and if the confidence interval does not cross 1, the association is taken as statistically significant. The results are explained in simple terms in Table 6 below. Table 6: Odds Ratio Analysis of Risk Factors for Dry Eye Disease Risk Factor Odds Ratio (OR) 95% Confidence Interval Interpretation Duration of DM > 10 years 3.80 1.32 – 10.94 Nearly 4 times higher risk Poor glycaemic control (HbA1c ≥ 7%) 3.29 1.28 – 8.45 About 3 times higher risk Diabetic retinopathy present 3.75 1.13 – 12.45 Nearly 4 times higher risk Age > 60 years 2.75 1.00 – 7.58 Nearly 3 times higher risk Female gender 1.44 0.57 – 3.66 Slightly higher, not significant In simple words, this table tells us that a diabetic patient who has had the disease for more than 10 years is nearly 4 times more likely to develop dry eye disease compared to one with a shorter duration of diabetes. Similarly, a patient with poor sugar control (HbA1c 7 per cent or more) has about 3 times higher chance of developing dry eye than a patient with well-controlled diabetes. The presence of diabetic retinopathy also nearly quadruples the risk of dry eye, which makes clinical sense, since retinopathy itself reflects long-standing and poorly-controlled diabetes affecting the microvasculature of the eye. Age above 60 years almost triples the risk, most probably because ageing itself causes reduction in tear secretion, which adds on to the diabetes-related damage. Female gender showed a mildly higher odds ratio of 1.44, but since the confidence interval crosses 1 (0.57–3.66), this finding was not statistically significant and should be interpreted with caution. 4.8 Clinical Management of Dry Eye in Diabetic Patients Every subject diagnosed with dry eye disease in this study was managed according to the severity of the disease, following a stepwise approach, in liaison with the physician managing the patient's diabetes. The management strategies adopted are described in detail below. Patients with mild dry eye disease (24 subjects) were managed conservatively with preservative-free artificial tear substitutes such as carboxymethylcellulose or sodium hyaluronate eye drops, to be instilled four to six times a day, along with counselling regarding lid hygiene, adequate blinking during prolonged screen use or reading, and avoidance of direct exposure to fans, air-conditioners and dusty environments. These patients were advised follow-up after four weeks to assess symptomatic improvement. Patients with moderate dry eye disease (20 subjects) were treated with more frequent instillation of lubricating eye drops, along with lubricating gel or ointment at bedtime to provide longer duration of corneal surface protection during sleep. In addition, a short course of topical anti-inflammatory therapy, such as low-dose topical corticosteroid for two weeks followed by topical cyclosporine, was considered in patients with significant ocular surface inflammation, under close monitoring of intraocular pressure. Warm compresses and lid massage were advised in patients having associated meibomian gland dysfunction, which is commonly seen in diabetic patients due to altered lipid metabolism. Patients with severe dry eye disease (10 subjects) required a more intensive approach. Along with preservative-free lubricants and topical cyclosporine, punctal occlusion using temporary collagen or silicone punctal plugs was performed in selected patients with very low Schirmer's values, to conserve the natural tears on the ocular surface. Protective spectacles/moisture chamber goggles were advised for outdoor use. Patients with associated corneal epithelial defects or punctate keratopathy were treated with bandage contact lens or autologous serum eye drops in a few refractory cases, along with vigilant monitoring for secondary infection. In all patients, irrespective of severity, strict emphasis was laid on optimisation of glycaemic control in coordination with the treating physician/endocrinologist, since good glycaemic control (HbA1c below 7 per cent) has been shown in this study, as well as in the existing literature, to reduce the severity and progression of dry eye disease. Patients were also counselled regarding periodic comprehensive eye check-up, including fundus examination for retinopathy, at least once a year, or more frequently if retinopathy or dry eye disease was already present. Patients with co-existing diabetic peripheral neuropathy were specifically counselled about reduced corneal sensitivity, which may mask symptoms of dry eye or early corneal injury, and were therefore advised more frequent dilated eye examination to prevent silent progression of ocular surface damage. Overall, this comprehensive and individualised approach to management, combining ophthalmic treatment with systemic glycaemic optimisation, was found to provide good symptomatic relief in the majority of patients over the follow-up period of the study, though a small proportion of patients with severe disease and long-standing uncontrolled diabetes required prolonged and combination therapy.

The present hospital-based cross-sectional study was undertaken to determine the prevalence, pattern and risk factors of dry eye disease among 84 patients with diabetes mellitus attending a tertiary care hospital of Jharkhand. Dry eye disease was found in 64.3 per cent of the study subjects, which is comparable to the prevalence of 54.3 per cent reported by Manaviat et al. in Iran and somewhat higher than the 33 per cent to 54 per cent range reported by various Indian studies, such as those conducted in Uttar Pradesh, Karnataka and Maharashtra9,10. This variation in prevalence across studies may be attributed to differences in diagnostic criteria applied for dry eye disease, geographic and climatic factors, duration of diabetes in the study population, and the cut-off values used for Schirmer's test and TBUT. In the present study, dry eye disease was slightly more common in females (68.4 per cent) as compared to males (60.9 per cent), although the difference was not statistically significant, which is in agreement with the findings of Kaiserman et al. and several other Indian studies that similarly did not find a strong gender-based predisposition to diabetic dry eye disease11,12,13. This can be explained by the fact that the pathophysiology of diabetic dry eye is primarily driven by autonomic and sensory neuropathy affecting the lacrimal functional unit, a mechanism which affects both genders relatively equally once significant hyperglycaemic damage has occurred, rather than being governed by hormonal factors alone, as is the case in age-related or menopausal dry eye disease seen in the general population14,15. A statistically significant association was observed between duration of diabetes and prevalence of dry eye disease in the present study, with prevalence rising from 41.7 per cent in patients with less than 5 years of diabetes to 80.0 per cent in those with more than 10 years of disease16,17. This finding is well supported by similar observations made by Seifart and Strempel, as well as by Yoon et al., who described a progressive decline in tear secretion and corneal sensitivity with increasing duration of diabetes, attributable to the cumulative neuropathic and microangiopathic damage to the lacrimal gland and corneal nerve plexus over time18. Regarding severity, the present study found that mild dry eye disease was the commonest presentation (44.4 per cent), followed by moderate (37.0 per cent) and severe disease (18.6 per cent). This distribution is broadly similar to the pattern reported in various hospital-based Indian studies, and reinforces the importance of early screening, since a substantial proportion of patients remain in the mild category and can be effectively managed with simple lubricant therapy if detected early, before progression to more severe and difficult-to-treat disease19,20. The odds ratio analysis in this study demonstrated that poor glycaemic control, longer duration of diabetes, presence of diabetic retinopathy and older age were the strongest independent risk factors for dry eye disease, each carrying nearly 3 to 4 times higher risk. These findings are consistent with the biological plausibility that chronic hyperglycaemia causes glycation of tear film proteins, reduced goblet cell density, and autonomic denervation of the lacrimal gland, all of which are more pronounced with longer duration and poorer control of diabetes21,22,23. The strong association between diabetic retinopathy and dry eye disease observed in this study is also supported by previous literature, which suggests that dry eye disease could be considered an additional microvascular marker of diabetes, similar to retinopathy and nephropathy, and could potentially be used as a simple, inexpensive bedside screening tool in resource-limited settings such as many parts of Jharkhand24,25. The relatively high prevalence of dry eye disease found in this study, coupled with the fact that many patients remained asymptomatic or attributed their mild symptoms to old age, underscores the importance of incorporating a simple dry eye screening protocol, such as a brief OSDI questionnaire, into routine diabetic eye check-up camps and outpatient clinics, particularly in a state like Jharkhand where access to specialised ophthalmic care is often limited to urban centres and tertiary hospitals26. This study has certain limitations that need to be acknowledged. Being a hospital-based cross-sectional study with a relatively modest sample size of 84 patients, the findings may not be entirely generalisable to the wider community-based diabetic population of Jharkhand. Additionally, cross-sectional design does not allow assessment of causality or the temporal progression of dry eye disease with worsening glycaemic control27. Larger community-based and longitudinal studies with bigger sample sizes are required to further validate and strengthen these findings, and to study the impact of long-term glycaemic optimisation on the natural course of diabetic dry eye disease28

Dry eye disease is a common and clinically significant, yet frequently under-recognised, ocular complication of diabetes mellitus, affecting nearly two-thirds of the diabetic patients examined in this study at a tertiary care hospital of Jharkhand. The disease was found to be significantly associated with longer duration of diabetes, poor glycaemic control and presence of diabetic retinopathy, while gender did not show a statistically significant influence. Nearly one in five affected patients had severe disease, highlighting the need for timely screening and intervention. These findings emphasise that dry eye disease deserves to be regarded as an important microvascular complication of diabetes mellitus, warranting the same degree of clinical attention as retinopathy, nephropathy and neuropathy. Recommendations 1. Routine ocular surface and dry eye screening, using simple bedside tests such as Schirmer's test and TBUT, should be incorporated as a part of the annual comprehensive eye examination of every diabetic patient, alongside fundus examination for retinopathy. 2. Diabetic patients with duration of disease exceeding 5 years, poor glycaemic control, or established diabetic retinopathy should be specifically prioritised for dry eye screening, given their significantly higher risk. 3. Health education regarding symptoms of dry eye disease and the importance of good glycaemic control should be provided to diabetic patients at the time of diagnosis itself, so that they can seek timely ophthalmic consultation. 4. Coordination between physicians, endocrinologists and ophthalmologists should be strengthened through joint diabetic eye clinics, particularly in tertiary care hospitals of Jharkhand serving a large rural catchment population. 5. Larger, multi-centric and community-based studies with longer follow-up are recommended to further establish the burden, natural history and long-term outcomes of dry eye disease in the diabetic population of the state.

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