|Ahead of print publication
A study of dry eye parameters in diabetics in a tertiary care hospital
Sakshi Patil, Sunita Bishnoi, Ajit Joshi
Department of Ophthalmology, Bharati Vidyapeeth (Deemed to be University) Medical College and Hospital, Sangli, Maharashtra, India
|Date of Submission||04-Mar-2020|
|Date of Decision||10-Jun-2020|
|Date of Acceptance||07-Jul-2020|
Junior Resident II, Bharati Hospital, Wanlesswadi, Sangli - Miraj Road, Sangli - 416 416, Maharashtra
Source of Support: None, Conflict of Interest: None
Aim: This study aims to study the frequency and severity of dry eye in diabetic patients and their correlation with duration of diabetes. Materials and Methods: This cross-sectional prospective study was conducted on all patients with diabetes mellitus presenting to ophthalmology department of a tertiary care hospital between November 1, 2019, and December 31, 2019. The study population included diabetic patients who were above the age of 40 years. Detailed ocular history including diabetic history was recorded and comprehensive ocular clinical examination to assess the dry eye status was done. Schirmer's I test and Tear film Break-Up Time (TBUT) tests were performed and results were recorded. Results: In this study, 100 eyes of 50 diabetic patients were subjected to dry eye tests. Varying degree of dryness was seen in 34 patients (68%). Schirmer's test was abnormal (<10 mm) in 24 patients (48%) and TBUT test was abnormal (<10 s) in 34 patients (68%). Majority of patients (60%) were asymptomatic. Statistically significant association was seen between the duration of diabetes with Schirmer's I test and TBUT test (P = 0.00). Conclusion: Dry eyes are a frequent association seen in patients with diabetes. Simple noninvasive tests for dry eyes such as Schirmer's test and TBUT test should be considered as an integral part of routine examination in diabetics as these may be asymptomatic.
Keywords: Hyperglycemia, Schirmer's I test, Tear Film Break-up Time, tear film
| Introduction|| |
According to txhe “International Dry Eye Workshop Study,” Dry Eye Syndrome (DES) is defined as an abnormality in quality or quantity of tears or in tear dynamics due to any cause resulting in ocular discomfort, visual disturbance, decreased tear film stability, and potential damage to the ocular surface.,
Diabetes mellitus (DM) is a major public health concern affecting 21.9% of city population in India. Chronic hyperglycemia, diabetic peripheral neuropathy, decreased insulin levels, microvasculopathy, and systemic hyperosmotic disturbances are risk factors for DM associated DES.,
This study highlights the correlation of severity of dry eyes tests with duration of diabetes.
| Materials and Methods|| |
This cross-sectional prospective study was conducted on all patients with diabetes presenting to ophthalmology department of a tertiary care hospital between November 1, 2019, and December 31, 2019. Study population included diabetic patients who were above the age of 40 years. Prior clearance from Institutional Ethical Committee was taken (IEC letter no. 377) and study was conducted according to tenets of Helsinki declaration.
- All patients with a history of diabetes and above the age of 40 years were included.
- Patients with other ocular disorder such as allergic eye disease, Vitamin A deficiency, Steven Johnsons syndrome, vernal keratoconjunctivitis, herpetic eye infections, Meibomian gland More Details dysfunction, and post ocular chemical burns
- Patients receiving systemic drug treatment such as MAO inhibitors, beta blockers, thiazides, non-steroidal anti-inflammatory drugs, and topical treatment such as alpha agonists and dry eye treatment
- Patients with a history of ocular surgery such as cataract and glaucoma surgery, pterygium excision, and refractive surgery
- Systemic diseases such as rheumatoid arthritis, Sjogren's syndrome, and lupus erythematosus
- Contact lens wearers.
Informed written consent of the subjects to participate in the study was taken. Demographic data and detailed history, was recorded on a predetermined pro forma. All patients were asked about duration of diabetes and history regarding dry eyes symptoms such as ocular discomfort, including soreness, gritty sensation, itchiness, redness, blurred vision that improves with blinking, photophobia, and excessive tearing., Ocular examination of all subjects was done which included visual acuity testing using Snellen's chart, anterior segment examination by slit lamp biomicroscopy, corneal sensation testing, intraocular pressure measurement using noncontact tonometer, fundus examination using direct, and indirect ophthalmoscope. Tear film break-up time (TBUT) test and the Schirmer's test are the most applied clinical tests used to diagnose DES and thus were done in this study. All investigations which needed topical anaesthesia were avoided. The dry eye status was studied by the following tests:
Schirmer test I
A 5 mm × 30 mm filter paper strip (no. 41 Whatman) was folded 5 mm from the end. The folded end was placed gently over the lower palpebral conjunctiva at its lateral one-third under aseptic precaution. The patient was advised to keep the eyes open and look upward. After 5 min, the strips were removed and the amount of the wetting was measured from the folded end of the strip [Figure 1].
Results after 5 min were graded as follows: >10 mm = normal, 8–10 mm = mild dry eye, 5–7 mm = moderate dry eye, <5 mm = severe dry eye.
Theoretically, Schirmer's I test with topical anesthesia would have been more objective and reliable in reflecting the status of dry eyes as it only measures basic secretion compared to without anesthesia which measures basic plus reflex secretion, but in practice, however, topical anesthesia cannot abolish all sensory and psychological stimuli for reflex secretion.Hence, in this study, all patients underwent Schirmer's I test without topical anesthesia.
Tear film break-up time
The lower fornix was stained using a presterilized strip of 2% fluorescein. The patient was advised to look straight without blinking while seated on a slit lamp and was observed using the broad beam of cobalt blue light. The time taken for the appearance of first random dark spot was noted.
Results of TBUT were graded as follows : >10 s = normal, 8–10 s = mild dryness, 5–7 s = moderate dryness, <5 s = severe dryness.
Data were entered into an excel sheet. Frequency and percentage were obtained for qualitative characters. Mean and standard deviation to see the association of duration of diabetes with dry eyes was obtained using ANOVA test. P < 0.05 was taken as statistically significant. Multinomial regression analysis was performed for dry eye tests and confounding factors such as duration of diabetes, age, and gender.
| Results|| |
In this prospective study, 100 eyes of 50 diabetic patients were examined. The age-sex distribution of these patients is shown in [Table 1].
The mean age of study population was 60.46 ± 9.744 years. Majority of patients both male and female were in the age group ranging between 61 and 70 years. The number of female patients (52%) in this study was higher when compared to male patients (42%).
The percentage of asymptomatic patients in this study was 60%. In symptomatic patients, majority of patients (20%) had burning sensation in both eyes, 12% patients had sensation of dryness in eyes and 2% patients had conjunctival congestion. Patients with no dry eye complaints but Schirmer's I and TBUT test positive were 18%. Anterior segment examination of majority of study patients did not show any significant signs of ocular surface damage to be included in the study. Distribution is shown in [Table 2].
[Table 3] depicts that according to Schirmer's I test grading, 26% of patients had mild dryness, 14% patients had moderate dryness, and 8% patients had severe dryness.
|Table 3: Grading of dry eyes using Schirmer's I test and its association with duration of diabetes|
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The mean duration of diabetes is longer in patients with severe dryness which is statistically significant (P = 0.00).
A multinomial logistic regression done for Schirmer's I test and various confounding factors showed that duration of diabetes is a significant predictor of severity but other confounding factors such as age and sex were not statistically significant.
[Table 4] depicts that according to TBUT test grading, 40% patients had mild dryness, 18% patients had moderate dryness, and 10% patients had severe dryness.
|Table 4: Grading of dry eyes using tear film break.up time test and its association with duration of diabetes|
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The mean duration of diabetes is longer in patients with severe dryness which is statistically significant (P = 0.00).
A multinomial logistic regression done for TBUT test and various confounding factors showed that the duration of diabetes is a significant predictor of severity (Chi-square [9, n = 50] = 33.423, Nagelkerke R2 = 0.529, P < 0.001), but other confounding factors such as age and sex were not statistically significant.
| Discussion|| |
Dry eye disease (DED) is a common association seen in patients with diabetes with decreased Schirmer's I test and TBUT values. Dry eye symptoms are typically severe in patients with longer duration of diabetes and these patients may report fewer dry eye symptoms.
The frequency of DED in this study was 68%. Nepp et al. in their study found 43% of their diabetics having DED. Damage to the microvasculature of the lacrimal gland accompanied by autonomic neuropathy might impair lacrimation in persons who suffer from diabetes for a long time.
The patients with aqueous deficiency dry eyes in our study were 48%, evaporative type dry eyes were in 8%, and mixed type was seen in 12%. Hyperglycemia and microvascular damage to the corneal nerves can block the feedback mechanism that controls the tear secretion. When the innervation of the ocular surface is disrupted, the lacrimal gland does not secrete tears properly.
The mean age of this study population was 60.46 ± 9.74 years. Aljarousha et al. in their study of 88 diabetic patients had patients with mean age of 55 ± 10.1 years.,
This study had a higher proportion of female patients which was similar to a study done by Khurana et al.
In this study, 40% patients had dry eye symptoms and 60% were asymptomatic. According to a Canadian dry eye epidemiology study, 37% of patients with diabetes had dry eye symptoms. Lack of symptoms may result from a reduction in corneal sensitivity caused by diabetic peripheral corneal neuropathy. Even a minimal decrease in corneal sensitivity is sufficient to cause changes in tear secretion.
In this study, the values of both Schirmer's I test and TBUT test is reduced in diabetic patients, which is similar to a study done by Dogru et al.
Majority of patients in this study had mild dryness; this could probably be due to majority of patients having shorter duration of diabetes. This is similar to a study done by Kamal et al. and Singh et al. where majority of patients had mild degree of dryness.,
This study showed that as the duration of diabetes increases the severity of dryness also increases which was statistically significant (P = 0.00). Similar association is confirmed by Zeng et al. and Manaviat et al. in their studies.
Small sample size and study being conducted in winter season are a potential limitation of this study. Relative lower humidity in winter season may act as an external factor for exacerbation of dry eyes.
Schirmer's I test performed lacks sensitivity as it does not provide good repeatability and in addition, it interferes with the tear reex.
The lack of a standardized procedure for applying uorescein to the tear lm is an important limitation concerned with TBUT test.
Further studies having large sample size and inclusion of standard dry eye questionnaire with recent diagnostic tests such as corneal esthesiometry, tear osmolarity testing, tear meniscus assessment, tear film interferometry, meibography, impression cytology of the conjunctiva will not only help in diagnosing DED but also will provide valuable insight into the potential mechanisms for DED in diabetics.
Lack of control group and glycemic parameters assessment especially HbA1C are other limitations of our study.
| Conclusion|| |
This study shows that most patients having diabetes have abnormal dry eye tests and the severity of dry eyes is associated with the duration of diabetes.
Despite the frequent association of diabetes and dry eye, this may be routinely overlooked in clinical practice as patients may be asymptomatic. Dry eyes can be easily detected by performing simple noninvasive tests such as TBUT and Schirmer's test and should be considered as a part of routine checkup.
Early diagnosis and timely management are important for prevention and progression of dry eyes.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Table 1], [Table 2], [Table 3], [Table 4]