Abstract
Purpose:
Dry eye syndrome (DES) is a global issue occurring due to tear deficiency or excessive tear evaporation. It is associated with a variety of symptoms causing ocular discomfort. The purpose of the study was to evaluate causative factors, treatment modalities, quality of life, and preservatives used in eye drops.
Methods:
This prospective, follow-up study was conducted in the ophthalmology outpatient department of a tertiary care teaching hospital. Patients older than 18 years of age of either sex diagnosed with DES and willing to give written informed consent were included. The patients were subjected to the Ocular surface disease index Questionnaire (OSDI Questionnaire) twice; at the time of the first visit and at 15 days follow-up.
Results:
A male preponderance was observed with a 1.86:1 male-to-female ratio. The mean age of the study population was 29.15 ± 10.07 years. The most common presenting complaints were symptoms related to dryness of the eyes followed by refractive error. Exposure to TV/computer screen for more than 6 hours is the most common causative factor. There was a statistically significant improvement in overall quality of life (QoL) in patients of DES on treatment. However, no significant difference was seen in the improvement of quality of life in comparison with different preservatives used in prescribed eye drops for the treatment of DES.
Conclusion:
DES can adversely affect the quality of life of patients. Prompt treatment of this condition can significantly improve the patient’s QoL. Physicians should be encouraged to perform quality of life evaluations for patients with DES to guide them in treatment with more individual-specific treatment options.
Keywords: Causative factors for dry eye syndrome, dry eye syndrome, preservative use, quality of life
Dry eye is a disorder of the tear film which occurs due to tear deficiency or excessive tear evaporation; it causes damage to the interpalpebral ocular surface and is associated with a variety of symptoms causing ocular discomfort. Dry eye syndrome (DES) is a common condition reported by patients who seek ophthalmologic care and is characterized by inflammation of the ocular surface and lacrimal glands.[1] Additionally, patients with dry eye are prone to potentially blinding infections, such as bacterial keratitis, and also at an increased risk of complications following common procedures such as laser refractive surgery.[1] The prevalence has been reported in many countries around the world, with a range between 9.5 and 90%.[2] Its management is done in a stepwise manner. In step 1, modification of the local environment and dietary changes along with lubricants are prescribed. If these measures are inadequate, in the second step 2, non-preserved lubricants, tear conservation by punctal occlusion, and prescription of topical antibiotics or topical glucocorticoids can be done. If these measures are inadequate, in step 3, oral secretagogues, allogenic serum eye drops, and sclera contact lenses can be tried, and if the condition does not improve by these measures, in step 4, topical corticosteroids for a longer duration, amniotic membrane grafts, and surgical punctal occlusion can be tried.[3] Its etiology includes aging, certain medical conditions like Sjogren’s syndrome, allergic eye disease, rheumatoid arthritis, lupus, scleroderma, graft vs. host disease, sarcoidosis, thyroid disorders, and vitamin A deficiency. Certain medicines and corneal nerve desensitivity caused by contact lens use, nerve damage, or laser eye surgery also cause DES.[1] It is learned that the use of certain preservatives in eye drop formulations can also be responsible for dry eye syndrome.[4]
World health organization (WHO) defines quality of life (QoL) as an individual’s perception of their position in life in the context of the culture and value systems in which they live and in relation to their goals, expectations, standards, and concerns.[5] Patients with dry eye experience various symptoms that can reduce their productivity and overall quality of life. For some patients, the severity of the condition and its chronicity leads to mood alterations and depression.[6] We intend to study the causative factors and treatment modalities of dry eye syndrome, to study the QoL of such patients, and to evaluate preservatives used in eye drops predisposing to dry eye syndrome.
Objectives
To study causative factors leading to dry eye syndrome, to observe the treatment modalities for dry eye syndrome in a tertiary care teaching hospital to measure QoL in patients with dry eye syndrome, evaluation of preservatives used in eye drops predisposing to dry eyes syndrome.
Methods
This study was carried out in the Ophthalmology department of a tertiary care teaching hospital. Data collection began after the approval of the Institutional Review Board. Those patients who were diagnosed as cases of DES, conforming to the inclusion criteria, were enrolled in the study. Written informed consent was taken from all the patients in their vernacular language. Data were collected for 8 weeks and were entered in the standard case record form. Details of drugs being used by the patients prior to complaints of dry eye were noted. Details of the treatment prescribed for DES in terms of brand name, generic name, dose, dosage form, frequency, and duration of treatment were also noted in the case record form. The preservatives present in these treatment modalities were also noted.
The severity of the dry eye in dry eye disease was assessed on the basis of the Dry Eye Workshop (DEWS) classification.[7] It was classified as severity levels 1, 2, 3 and 4, where 1 suggested mild DES, 2 suggests moderate DES, 3 suggests severe DES, and 4 suggests severe disabling DES. The quality-of-life assessment was done by the Ocular surface disease index Questionnaire (OSDI Questionnaire).[8] Patients were subjected to the questionnaire twice; at the time of the first patient visit and at follow-up after 15 days. The questionnaire had three subscales: ocular symptoms, vision-related function, and environmental triggers. Patients rated their responses on a 0 to 4 scale with 0 corresponding to “none of the time” and 4 corresponding to “all of the time.” A final score was calculated which ranges from 0 to 100 with scores 0 to 12 representing normal QoL, 13 to 22 representing mildly affected QoL, 23 to 32 representing moderately affected QoL, and greater than 33 representing severely affected QoL. Evaluation of improvement in quality of life was done in comparison with OSDI questionnaire at the time of the first visit and at 15-day follow-up and post-treatment. Patients of either sex, above the age of 18 years who have been diagnosed to be suffering from DES, and patients willing to give written informed consent were included in the study. Patients with psychiatric illness and patients with acute eye conditions (acute conjunctivitis, acute attack of angle closure glaucoma, episcleritis, scleritis, etc.) were excluded from the study.
Study design: A prospective, observational follow-up study.
Sample size: Duration based.
Statistical analysis
Complete data were entered in Microsoft Excel 2019 and SPSS software (Statistical Package for Sciences) version 24 (IBM Corporation, California). Paired t test and one-way ANOVA were used. P value <0.05 was considered statistically significant. Pearson correlation test has also been used to check the correlation between age and severity of DES.
Results
A total of 40 patients fulfilling the inclusion and exclusion criteria were enrolled in the study.
Demographic characteristics of the study population
The mean age of the study population was 29.15 ± 10.07 years. The young population in the age range of 26–35 years was most affected by DES followed by the 16–25 years age range. Fig. 1.
Figure 1.
Age distribution of study population
Males had greater preponderance to DES, with male to female ratio of 1.86:1. Occupational profile of patients included business (n = 3), service (n = 17), farming (n = 2), student (n = 11), housewife (n = 5), and factory worker (n = 2). A higher incidence of DES was seen in patients with service (n = 17), followed by students (n = 11).
Severity of dryness of eyes in the study population
The severity of DES was classified on the basis of Dry Eye Workshop (DEWS) classification into mild, moderate, and severe which was seen in 20%, 42%, and 38% of patients, respectively.
Age and severity of DES correlation
Pearson correlation test was used to check the correlation between age and severity of DES. The value was found to be 0.07 suggesting a very weak correlation.
Comorbidities
There were only two patients with comorbidities; diabetes plus hypertension (1 patient) and rheumatoid arthritis (1 patient).
Presenting complaints
The different presenting complaints were symptoms related to dryness of the eyes which included a stinging or burning sensation in the eyes, a foreign body sensation, sensitivity to light, redness of the eyes, etc., (20 patients). Complaints related to refractive error (15 patients), glaucoma (2 patients), and cataract (2 patients) were also noted. One patient had both glaucoma and complaints related to symptoms of dryness. Most patients presented with complaints related to symptoms of dryness of the eye followed by refractive error.
Quality of life (QoL) scores in patients of des according to probable causative factors
Probable causative factors included exposure to TV/computer screens for more than 6 hours, exposure to fumes and dust, benzalkonium chloride, and rheumatoid arthritis. Among these, exposure to TV/computer screen was the most common causative factor seen in 22 patients. Mean OSDI scores for rheumatoid arthritis patient were the highest (21) followed by benzalkonium chloride (18.8 ± 9.28) and those having exposure to fumes and dust (18.5 ± 6.42) Table 1.
Table 1.
Probable causative factors for DES and mean OSDI scores
| Causative factors | No. of patients | Mean OSDI score |
|---|---|---|
| Exposure to TV/computer screen | 22 | 11.81±6.11 |
| Exposure to fumes and dust | 4 | 18.5±6.42 |
| Benzalkonium chloride | 5 | 18.8±9.28 |
| Rheumatoid arthritis | 1 | 21 |
| No causative factors | 8 | 15.62±11.24 |
Treatment prescribed for DES to the study population
The disease-specific drugs for DES prescribed to the study population included sodium carboxymethyl cellulose (0.5%), cyclosporine (0.09%), hydroxypropyl methyl cellulose (0.3%), sodium hyaluronate (0.1%), polymixin B (0.1%)+ phenyl mercuric nitrate (0.001%), loteprednol etabonate (0.5%), and chloramphenicol (0.5%). Among them, sodium hyaluronate was prescribed the most followed by hydroxypropyl methyl cellulose and sodium carboxymethyl cellulose. Patients prescribed single, two, and three disease-specific medications were 42.55%, 25%, and 32.50%, respectively. The role of cyclosporin, polymixin B, and chloramphenicol was for the prevention of secondary bacterial infections and not as lubricants. Table 2.
Table 2.
Treatment for DES prescribed to the study population
| Treatment | No. of patients |
|---|---|
| Sodium carboxymethyl cellulose (0.5%) | 13 |
| Cyclosporine (0.09%) | 9 |
| Hydroxypropyl methylcellulose (0.3%) | 14 |
| Sodium hyaluronate (0.1%) | 20 |
| Polymixin B (0.1%) + phenyl mercuric nitrate (0.001%) | 2 |
| Loteprednol etabonate (0.5%) | 1 |
| Chloramphenicol (0.5%) | 3 |
Preservatives present in the prescribed treatment
Patients were prescribed different eye drops for treatment of DES which contained various preservatives. These preservatives were stabilized oxychloro complex (0.1%), benzalkonium chloride (0.01%), carbomer polymer c (0.3%), polyethylene glycol (0.4%)+ propylene glycol (0.3%), polymixin B sulfate (0.1%), phenylmercuric N (0.001%), D panthenol (5%), and sodium perborate (0.03%). Stabilized oxychloro complex was most common preservative followed by benzalkonium chloride. Eight patients were prescribed medications without preservative. Three patients were prescribed eye drops containing more than one preservative. Fig. 2.
Figure 2.
Preservatives present in prescribed treatment
Quality of life analysis
Quality of life analysis was done by the Ocular surface disease index Questionnaire (OSDI Questionnaire). Patients were subjected to OSDI questionnaire twice, at baseline and at follow-up visit at 15 days. Mean OSDI score at baseline was 14.35 ± 8, and after 15 days, it was 4.98 ± 4.2. Paired t test was used in comparison with baseline and after 15 days QoL scores and it was statistically significant (P < 0.001) Table 3.
Table 3.
Improvement in relation to individual preservatives present in eye drops used for the treatment of DES and overall improvement in QoL in patients with DES
| Mean OSDI score | Difference | ||
|---|---|---|---|
|
| |||
| 1st visit (baseline) | 2nd visit (follow-up) | ||
| Stabilized oxychloro complex (0.1%) | 14.38 | 5.13 | 9.25 |
| Benzalkonium chloride (0.001%) | 13.44 | 5.00 | 8.44 |
| Carbomer polymer c (0.3%) | 12 | 7 | 5.00 |
| Polyethylene glycol (0.01%) + propylene glycol (0.3%) | 19 | 10 | 9.00 |
| Polymixin b sulfate (0.1%) | 12.5 | 3.0 | 9.50 |
| Phenylmercuric N (0.001%) | 14.5 | 4.5 | 10.00 |
| D panthenol (5%) | 14.5 | 4.5 | 10.00 |
| Sodium perborate (0.03%) | 10.5 | 1.5 | 9.00 |
| Overall improvement in QoL | 14.35 | 4.98 | 9.37* |
*Mean OSDI score difference with P<0.001 suggesting significant difference
Quality of life scores in relation to active ingredients present in eye drops
We compared the active treatment groups carboxymethyl cellulose, sodium hyaluronate, hydroxypropyl methyl cellulose, a combination of hydroxypropyl methyl cellulose + sodium hyaluronate, and a combination of hydroxypropyl methyl cellulose + carboxymethyl cellulose + sodium hyaluronate with the use of one-way ANOVA to evaluate any significant differences between them for improvement of QoL. However, on comparing different active ingredients with each other, we did not find a statistically significant difference among them. The improvement in OSDI score was highest in patients taking carboxy methyl cellulose (mean OSDI = 10.42) and least for patients taking hydroxy propyl methyl cellulose (mean OSDI difference = 5.8).
Quality of life scores in relation to preservatives present in eye drops
The mean OSDI score difference between baseline and 15 days follow-up was highest with phenylmercuric N and D panthenol (score difference of 10) and least with carbomer polymer c. We applied one-way ANOVA test to check significance of the difference in the improvement of QoL scores between individual preservative groups but did not find a statistically significant difference (P value <0.94) Table 3.
Mean OSDI scores in relation to the severity of dryness in DES patients
Mean OSDI baseline scores for mild, moderate, and severe dryness in patients of DES were 14.12 ± 11.73, 15.94 ± 6.73, and 12.67 ± 7.18, respectively. The difference between them was not significant.
Comparison of improvement in mean OSDI score in relation to the presence or absence of preservatives in eye drops used for the treatment of DES
Thirty-two patients prescribed eye drops for the treatment of DES contained preservatives, and in eight patients, the prescribed eye drops did not contain any preservatives. A greater difference in pre- and post-OSDI scores was seen in patients prescribed eye drops without preservatives, but the difference was not statistically significant as compared to those prescribed eye drops with preservatives.
OSDI scores in relation to individual domains in the OSDI questionnaire
The effects on individual domains in the OSDI questionnaire, namely, OSDI symptoms (Domain 1), OSDI function (Domain 2), and OSDI triggers (Domain 3) were evaluated based on the mean difference of OSDI scores in individual domains at baseline and at 15 days follow-up. Domain 2 had more improvement in OSDI score (3.3) compared with Domain 1 (2.92) and Domain 3 (3.15). However, the difference was not statistically significant (P = 0.64).
Discussion
In our literature search, we found the prevalence of DES in India to be 17.7%, however, that in western India was higher at 34.26%.[9,10] There were negligible studies in India evaluating causative factors, quality of life, and effects of active ingredients and preservatives used in eye drops on DES simultaneously, which prompted us to take up this study.
Patients with the greater preponderance of DES were in the 26–35 years of age group. The mean age of the study population was 29.15 ± 10.07 years. In our study, males had more preponderance to DES than females, with male to female ratio of 1.86:1. A study done by McCarty et al.[11] found a higher prevalence among women. Another study suggested that the prevalence of DES increases with age and doubles after 59 years of age.[12] However, we found a very weak correlation of age with DES (Pearson correlation coefficient = 0.07). One probable reason for this could be a small sample size. A study done by McCarty et al.[11] suggested that the 21–40 years of age group is associated with more severe DES. This age range is comparable to our study. Another study was done by Schein et al.[13] in 2520 patients found no association between age and sex with dry eye.
The occupational profile of study participants included business, service, farming, student, housewife, and factory workers. Patients who were in service had a higher incidence of DES (n = 17), followed by students (n = 11). One likely reason could be higher exposure to TV/computer screens in these patients. A study done in North India showed that patients involved in desk jobs involving computer use were more predisposed to develop DES,[14] which is in accordance with our study. There were only two patients with comorbidities like diabetes, hypertension, and rheumatoid arthritis in our study. The presenting complaints of patients who were diagnosed with DES included symptoms related to dryness of eyes (a stinging or burning sensation in eyes, a foreign body sensation, sensitivity to light, redness of the eyes, etc.), complaints related to refractive error, glaucoma, and cataract. Most patients presented with symptoms related to dryness of the eye (n = 21) followed by refractive error (n = 15). We assessed the severity of DES on the basis of the Dry Eye Workshop (DEWS) classification. Patients having mild, moderate, and severe DES were 20%, 42%, and 38%, respectively.
DES is a multifactorial disease with possible overlapping causes. In our study, probable causative factors included exposure to TV/computer screens for more than 6 hours daily, exposure to fumes and dust, benzalkonium chloride, and rheumatoid arthritis. Among these, exposure to TV/computer screens was the most common causative factor seen in 22 patients, which was observed to be a common causative factor in a few other studies, too.[14] Mean OSDI score was more for benzalkonium chloride (with a mean OSDI score of 18.8 ± 9.28) as a causative factor suggesting more severe DES in these patients. Other studies also suggest that benzalkonium chloride is an important causative factor for severe DES.[15]
The drugs prescribed to the study population with DES which was disease-specific include sodium carboxymethyl cellulose, cyclosporine, hydroxypropyl methyl cellulose, sodium hyaluronate, polymixin B + phenyl mercuric nitrate, loteprednol etabonate, and chloramphenicol. Among them, sodium hyaluronate was prescribed the most followed by hydroxypropyl methyl cellulose and sodium carboxymethyl cellulose. Based on the number of disease-specific medications prescribed for DES; 42.55% of patients were prescribed 1 medication; 25% of patients were prescribed two medications and 32.50% of patients were prescribed three medications for the treatment of DES.
The eye drops prescribed for the treatment of DES contained different preservatives. The primary role of the preservative is to maintain the sterility of the eye drops. For this, they act as a detergent or by oxidative mechanisms or some other nonspecific antimicrobial mechanism. As the eye drops may be used for a considerable period of time some of these preservatives like benzalkonium chloride on repeated use may themselves be responsible for causing damage to the ocular surface.[4] Studies have reported a better outcome with the use of preservative-free eye drops as compared to preservative-containing eye drops.[15] Common preservatives used in our study were stabilized oxychloro complex, benzalkonium chloride, carbomer polymer c, polyethylene glycol + propylene glycol, polymixin B sulfate, phenylmercuric N, D panthenol, and sodium perborate. Among these, stabilized oxychloro complex was the most common preservative followed by benzalkonium chloride. Benzalkonium chloride is a commonly used preservative in eye drops. This is in accordance with other studies.[4,15]
In this study, quality of life analysis was done by Ocular surface disease index Questionnaire (OSDI Questionnaire), where patients were subjected to the OSDI questionnaire twice, at baseline and at follow-up visits at 15 days. We used the paired t test to compare the scores at baseline and after 15 days. Mean OSDI score at baseline was 14.35 ± 8 and after 15 days it was 4.98 ± 4.2 (P value <0.001), which implies that there was statistically significant improvement after follow-up. A study done by Lopes et al.[16] also showed improvement in OSDI scores after the substitution of benzalkonium chloride preserved prostaglandin eye drops by a preservative-free prostaglandin analog. Another study done by Mateo-Otobia et al.[17] also showed that preservative-free eye drop formulation containing sodium hyaluronate and trehalose has a better OSDI score compared to eye drops containing preservatives. The mean OSDI score at baseline was in the range of mildly affected quality of life and the mean score at follow-up was in the range of normal QoL. In our study, mean OSDI scores in patients with mild, moderate, and severe dryness of the eyes were all in the range of mildly affected QoL which is difficult to explain. One probable reason could be can be due to subjective variation in responses given by patients to the OSDI questionnaire.
We evaluated the effect of different active ingredients used for the treatment of DES in the treating eye drops based on the OSDI QoL scores. The mean OSDI score difference was highest with carboxy methyl cellulose (mean OSDI difference = 10.42). The mean OSDI score difference was least with hydroxy propyl methyl cellulose (mean OSDI difference = 5.8). However, on the application of one-way ANOVA to check for the difference in the improvement of QoL scores in relation to active ingredients, we did not find a statistically significant difference.
We also evaluated the effect of preservatives used in treating eye drops on the OSDI QoL scores. The mean OSDI score difference was highest with D panthenol and phenylmercuric N (mean OSDI difference = 10). The mean OSDI score difference was least with carbomer polymer c (mean OSDI difference = 5). However, on the application of one-way ANOVA to check for differences in the improvement of QoL scores in relation to individual preservatives, we did not find a statistically significant difference. A study done by Debbasch et al.[18] suggests the cytoprotective effect of carbomer polymer c which is in contradiction with our study result which shows the poor response with carbomer polymer c.
We also tried to evaluate the difference in QoL scores among patients in whom the prescribed eye drops did not contain any preservatives as compared to those in whom the prescribed eye drops contained preservatives. Thirty-two patients were prescribed eye drops containing preservatives and eight patients were prescribed eye drops that did not contain any preservative. OSDI scores of patients who were prescribed eye drops without preservatives had a greater difference in their pre- and post-OSDI scores as compared to those who had preservatives in their prescribed eye drop suggesting a better outcome with preservative-free eye drops. However, the difference was not statistically significant. One probable reason for this could be a small sample size. A prospective epidemiological survey carried out by 249 ophthalmologists on 4107 patients suggested less incidence of DES when preservative-free eye drops were used.[19] Other studies also have similar results in this regard.[15]
OSDI questionnaire contained three domains, namely, OSDI symptoms (Domain 1), OSDI function (Domain 2), and OSDI triggers (Domain 3). We tried to evaluate the difference in improvement in the individual domains based on the mean difference of OSDI scores with regard to individual domains at baseline and at 15 days of follow-up. The difference between the three domains was negligible and not statistically significant. This suggests that there is equivalent improvement in all three domains of the OSDI Questionnaire.
Our study and other studies[20,21] suggest that DES has a negative impact on several aspects of quality of life. There is the improvement of QoL in the treatment of DES with the prescribed treatment. We found exposure to a computer/TV screen for more than 6 hours to be the most common causative factor. The most common treatment modality was the use of eye drops containing sodium hyaluronate. Stabilized oxychloro complex was the most common preservative used in our study. Both, in relation to the active ingredients and the preservatives used in treating eye drops, there was no statistically significant difference within the active ingredients and also within preservatives in improvement in QoL scores. Though preservative-free eye drops showed a better improvement in QoL as compared to preservative-containing eye drops, the difference was not statistically significant.
Strengths of the Study
This study not only evaluates treatment modalities in DES but also assesses the causative factors, and effects of different preservatives in eye drop on the prognosis of DES and quality of life using a robust quality of Life (QoL) questionnaire, that is, Ocular surface disease index Questionnaire (OSDI Questionnaire).
This study also analyzed improvement in each domain of the OSDI Questionnaire like OSDI symptoms, OSDI function, and OSDI triggers after treatment.
Limitations of the Study
This study was a duration-based study, so a limited sample size of 40 patients was collected. Hence, the lacunae associated with a small sample size are present.
We did not compare the quality of life among patients receiving either single, dual, or more than two drugs for the treatment of DES with each other due to this sample size.
Conclusion
Prevention of exposure to causative factors, early diagnosis, and prompt treatment preferably with preservative-free treatment modalities may result in a better clinical outcome. Physicians should be encouraged to perform quality of life evaluations for patients with DES to guide them in treatment with more individual-specific treatment options. Different treatment options can be evaluated based on the severity of the disease and prescription patterns can be modified accordingly.
Financial support and sponsorship
Nil.
Conflicts of interest
There are no conflicts of interest.
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