Dry eye disease is a complex ocular surface disorder caused by multiple factors brought on by a vicious cycle of loss of hemostasis of the tear film, persistent inflammation, hyperosmolarity and neurosensory disturbance play an important role¹. The symptoms of dry eye disease include sensation of a foreign body, burning, stinging, redness, itching, and photophobia. Stable tear film is also a very good indicator of good ocular health. Dry eye is divided into two main types the first being due to less tear secretion and the second being due to more tear evaporation.²A decreased muco-aqueous component in the tear film can result in excessive evaporation from the ocular surface which is usually caused by deficiency of the lipid component in the tear film³, whereas aqueous deficiency which is caused by decreased production is typically caused by autoimmune or systemic conditions or by the dysfunction of the lacrimal gland or obstruction of the lacrimal gland. Mixed cases of the 2 types can also be found in patients with dry eyes.⁴The main causes of dry eye disease are tear hyperosmolarity and tear film instability brought on by ocular surface and lacrimal functional unit dysfunction. Through neuronal connections, the effects of hyperglycemia on any part of the lacrimal functional unit can spread across the entire system, resulting in irregular blinking, changes in the composition of the tear film, and either excessive or insufficient tear production.⁵  There may be a deficient tear film due to reduction in the Meibomian gland epithelial cells and goblet cells which may occur in cases of insulin resistance or deficiency and long‐standing hyperglycemia. Type 2 diabetes mellitus causes structural anomalies in the corneal nerve fibers leading to decreased sensitivity and even autonomic neuropathy^6-7. This results in a decrease in blink rate, which raises ocular discomfort by causing the tear film to evaporate excesively.⁸ The dry eye disease can be assessed by Ocular Surface Disease Index (OSDI) questionnaire which is a self-administered 12 item questionnaire of grading of ocular symptoms over a 2 to 4 week period with score ranging from 0 to 100.  Then the dry eye can be graded as normal (0-12 points)⁹, mild dry eye (13-22 points), moderate dry eye (23-32 points) and severe dry eye (33-100 points).Tear film breakup time test (TBUT) can be calculated using wet fluorescein-impregnated strip placed in lower fornix and then removing it^10,11,12.  Appearance of dry spot or line before 10 seconds is considered abnormal and documented as dry eye. (Normal range - 15 to 35 seconds) Another test which is Schirmer’s test is used for diagnosing dry eye. Following five minutes of eyelid closure, the wetness of the filter paper strip is measured after taking out both strips from the fornices at the same time. Wetting of less than 10 mm strip is considered abnormal and documented as dry eye.¹³    Various studies found out the relationship between diabetes and dry eye disease and concluded that patients with type 2 diabetes have significantly higher prevalence of dry eye disease(especially moderate dry eye), than people without the diabetes.  Even moderate dry eye disease affected corneal nerve sensitivity more and severity of diabetic retinopathy correlated with severity of dry eye disease.  One study found that dry eye disease is significantly associated with older age and increasing duration of diabetes.¹⁴ Another study showed that diabetic retinopathy and dry eye symptoms and signs were significantly associated with each other and with the increasing severity of diabetic retinopathy and HbA1c the sign and symptoms also increased.  The preceding studies have revealed that the diabetics are more prone to dry eye disease, and this affects the everyday quality of life of the people including the physical (dry eye disease being a type of chronic pain syndrome), social and psychological domains, thus affecting the workplace productivity¹⁵. 

AIM

To compare the severity of dry eye in  type 1 diabetics with those in type 2 diabetics

This observational study was conducted over 18 months in the outpatient departments of Ophthalmology and Medicine at Mahatma Gandhi Medical College and Hospital, Jaipur. A total of 204 participants, aged 18–60 years, were divided into two groups: 102 known diabetics (cases) and 102 non-diabetics (controls). The sample size was calculated based on a 17% expected difference in dry eye prevalence between the groups, with 80% power and a 5% significance level. Participants with other ocular surface diseases, systemic causes of dry eye, prior ocular surgery, or those unwilling or unable to cooperate were excluded.

Table: 1- Distribution of study subject according to Gender (N=204)

In this study among cases 47(46.08%) and 55 (53.92%) and among controls 49(48.04%) and 53(51.96%) study subjects were males and females respectively. Females were more in number and female to male ratio was 1.17:1 for cases and 1.08:1 for controls.

Table:2 - Distribution of study subject according to Smoking Habit (N=204)

In this study among cases 72 (70.6%), 15 (14.7%) and 15 (14.7%) study subjects and among controls 76 (74.5%), 13 (12.7%) and 13 (12.7%) study subjects never smoked, were current smoker and past smoker respectively. 

Table:3 - Distribution of study subject according to Type of Diabetes (n=102)

Among the cases 16 (15.7) were suffering from Type 1 Diabetes and 86 (84.3%) were suffering from Type 2 Diabetes.

Table: 4- Distribution of study subject according to HbA1c Level (n=102)

In this study among the cases 34 (33.3%) were having HbA1c < 6.5 %, 45 (44.1%) were having HbA1c 6.5 to 8 % and 23 (22.5%) were having HbA1c level > 8 %. The mean HbA1c level was 7.17+0.91 %

Table 5: Distribution of Cases with Dry Eye (Schirmer Test) according to Duration of Diabetes (n=102)

Among the cases with duration of diabetes < 5 yrs., 6- 10 yrs. and >10 yrs.  11(73.3%) 5(11.4%) and 0(0%) were not suffering from any dry eye. Among the cases with duration of diabetes < 5 yrs., 6- 10 yrs. and >10 yrs.,   4(26.7%), 39(88.6%) and 43(100%) were suffering from dry eye respectively. So as duration of diabetes increases the number of study subject with dry eye increases. (P< 0.001)

Table 6: Distribution of Cases with Dry Eye (Schirmer Test) according to Type of Diabetes (n=102)

Among the cases with type 1 6 (37.5%) diabetes were not suffering from dry eye and 10(62.5%) were suffering dry eye. Among the cases with type 2 diabetes 10(11.6%) were not suffering from dry eye and 76(88.4%) were suffering from dry eye. This different was not statistically significant. (p>0.05)

Table 7: Distribution of Cases with Dry Eye (Schirmer Test) according to HbA1c Level (n=102)

Among the cases with HbA1c < 6.5 % all 13(100%) were not having any dry eye; among the cases with HbA1c between 6.5 to 8 % total 41(93.2%) were suffering from dry eye and finally among cases with HbA1c > 8% all 45(100%) were suffering from dry eye. So dry eye was more associated with cases with higher HbA1c and this difference was

statistically significant. (p<0.001)

Figure 1,2: Table Distribution of study subject according to OSDI Categorization and TBUT (n=204)

Graph shows significantly higher prevalence of moderate to severe dry eye among diabetic patients compared to non-diabetics, based on both OSDI and TBUT assessments (P<0.001).

In this study among cases 47(46.08%) and 55 (53.92%) and among controls 49(48.04%) and 53(51.96%) study subjects were males and females respectively. Out of total 204 study subject there were 108 (52.9%) females and 96 (47.1%) males .Females were more in number and female to male ratio was 1.17:1 for cases and 1.08:1 for controls. Lamba et all¹⁷(2023) in a similar study found the mean age of study participant to be 53.2±9.7 with majority of the respondents being females 107(53%).

In this study among cases 72 (70.6%) study subject never smoked, 15 (14.7%) were current smoker and 15 (14.7%) were past smoker study subjects. Among controls 76 (74.5%) never smoked, 13 (12.7%) were current smoker and 13 (12.7%) study subjects were past smoker.  Bashorun et all ¹⁸ (2024) reported in their study that majority i.e. 172 (86.43%) had never smoked a cigarette.

In our study among the diabetic cases 16 (15.7) were suffering from Type 1 Diabetes and 86 (84.3%) were suffering from Type 2 Diabetes. In this study we also divided the cases i.e. diabetic patients into type 1 and type 2 diabetes with as prevalence of type 2 is much more than type 1, we also found the same in our study .But most other similar studies 16,121,124,128 either recruited type 2 diabetes patients or did not segregated the patients into type 1 and type 2 diabetes.

In this study the mean HbA1c level was 7.17+0.91 %. Among the cases 34 (33.3%) were having HbA1c < 6.5 %, 45 (44.1%) were having HbA1c 6.5 to 8 % and 23 (22.5%) were having HbA1c level > 8 %. So most of the patients were having HbA1c between 6.5 to 8%. Bashorun et all 8 (2024) reported in their study that for the diabetic group, (65%) had glycosylated hemoglobin (HbA1c) values of ≥6.5%  and  Sarkar et all¹⁹ (2021) found the majority diabetic patients  with good to fair control (58%).

In our study the dry eye was detected among study subjects using OSDI score and TBUT test and study subjects were labelled as having dry eye by doing Schirmer Test. The mean OSDI score of the study subject was 15.11205. As per OSDI score 81(39.7%) 51 (25%) 55 (26.9%) and 17 (8.3%) were categorized as having no dry eye, mild dry eye, moderate dry eye and severe dry eye respectively. So total 123 (60.3%) were suffering from dry eye as per OSDI score. Now we categorized the cases and control according to OSDI category and found that among the cases 63 (61.8%) were not having any dry eye and were having mild dry, moderate dry eye and severe dry eye respectively. Similarly, among controls 29 (28.4%) were not suffering from dry eye and rest 29 (28.4%), 9 (8.8%) and 1 (0.9%) were having mild dry, moderate dry eye and severe dry eye respectively. So among the controls number of study subjects with moderate and severe dry eye are more and this difference was statistically significant. (P<0.001)

 On doing TBUT test Among cases it was found that 68 (66.7%) were suffering from mild to moderate and 15 (14.7%) were suffering from severe dry eye disease and among controls 35 (34.3%) were suffering from mild to moderate dry eye disease and 4 (3.9%) were suffering from severe dry eye disease as per TBUT test. So among diabetics mild to moderate and severe dry eye was more prevalent compared to non-diabetic and this difference was statistically significant. (p<0.001) Manchikanti et all ¹²⁰ (2021) in their similar study found that in diabetic group , 16 patients (76.2%) had moderate‐to‐severe dry eye symptoms and non-diabetic group  had most of the patients (90.5%) with normal to mild dry eye symptoms based on OSDI. The average OSDI score was 42.95± 17.38 and 16.75 ± 5.45 in cases and controls, respectively. Diabetic group had a lower Schirmer I, Schirmer 2, and TBUT which was statistically significant (P < 0.01). In our study the mean OSDI score of the study subject was 22.75+16.56 and diabetic group had a lower Schirmer I and TBUT which was statistically significant (P < 0.01) 

This study found a higher prevalence and severity of dry eye disease among diabetic patients compared to non-diabetics, as assessed by OSDI score, TBUT, and Schirmer test. Females were slightly more represented, with a female-to-male ratio above 1 in both groups. Type 2 diabetes was predominant among the cases, and most had HbA1c levels indicating fair glycemic control. Dry eye symptoms were significantly more common and severe in the diabetic group, with 70% showing mild to severe dry eye on TBUT. The difference between diabetic and non-diabetic groups was statistically significant (P < 0.001). These findings highlight the importance of routine dry eye screening in diabetic patients.

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