Comparison of the Efficacy of Carboxymethylcellulose 0.5%, Hydroxypropyl-guar Containing Polyethylene Glycol 400/Propylene Glycol, and Hydroxypropyl Methyl Cellulose 0.3% Tear Substitutes in Improving
- संदीप पांडेय
- Jul 2
- 8 min read
PURPOSE:
To compare the efficacy of carboxymethylcellulose 0.5% (CMC), hydroxypropyl-guar containing polyethylene glycol 400/propylene glycol (PEG/PG), and hydroxypropyl methylcellulose 0.3% (HPMC) as tear substitutes in patients with dry eye.
METHODS:
A retrospective evaluation of cases presenting with symptoms of dry eye from July 2014 to June 2015 was done. Patients with Ocular Surface Disease Index (OSDI) scoring >12 were included in the study. Parameters such as age, gender, Schirmer test (ST), and tear film breakup time (TBUT) were recorded on day 0, week 1, and week 4. For analysis, cases were divided into three groups; Group 1 – CMC, Group 2 – PEG/PG, and Group 3 – HPMC.
RESULTS:
Overall, 120 patients were included in the study. Demographic data and baseline characteristics were comparable among the groups. Group 2 had significant improvement in percentage change in OSDI (weeks 0–1, 0–4, and 1–4, P = 0.00), TBUT (weeks 0–1, P = 0.01; 0–4, P = 0.006; and 1–4, P = 0.007), and in ST (weeks 0–1, P = 0.02; 0–4, P = 0.002; and 1–4, P = 0.008) compared to Group 1 at all follow-ups. Group 3 had improvements similar to Group 2, but it was not at all follow-ups (improvement in percentage change OSDI [weeks 0–1, 0–4, and 1–4, P = 0.00], TBUT [weeks 0–1, P = 0.10; 0–4, P = 0.03; and 1–4, P = 0.04], and in ST [weeks 0–1, P = 0.007; 0–4, P = 0.03; and 1–4, P = 0.12]). No significant difference was found between Groups 2 and 3.
CONCLUSIONS:
Hydroxypropyl-guar containing PEG/PG and HPMC as tear substitutes are better than CMC. While HPMC was comparable to PEG/PG in subjective improvement, the objective improvement was not consistent.
Keywords: Artificial tear, carboxymethylcellulose, dry eye, hydroxypropyl methylcellulose, Ocular Surface Disease Index, polyethylene glycol
Introduction
Dry eye is a multifactorial disease of the tears and ocular surface that results in symptoms of discomfort, visual disturbance, and tear film instability, with potential damage to the ocular surface.[1] It is accompanied by increased osmolarity of the tear film and inflammation of the ocular surface.[1] Dry eye is one of the most common causes of ocular morbidity in patients presenting to an ophthalmology outpatient department. Approximately one out of seven individuals aged 65–84 years reports symptoms of dry eye often or all of the time.[2] Management of dry eye depends on the cause and severity of the condition.[1] Various strategies have been described for medical management of dry eye; these include, the topical use of lubricants (artificial tear substitutes), topical corticosteroids and anti-inflammatory therapies, cyclosporine ophthalmic emulsion, and the systemic use of antioxidants (e.g., omega-3 fatty acids).[1,2]
Artificial tears are aqueous solutions containing polymers that determine their viscosity, retention time, and adhesion to the ocular surface. Various polymers currently in use include cellulose derivatives (e.g., hydroxypropyl methylcellulose [HPMC], carboxymethylcellulose [CMC]), polyvinyl derivatives (e.g., polyvinyl alcohol), chondroitin sulfate, and sodium hyaluronate.[1,3] In mild-to-moderate cases, they are the mainstay of treatment. Artificial tears act by replenishing the deficient aqueous layer of the tear film and diluting the inflammatory cytokines.[1,2,3]
In this study, we compared the efficacy of three commonly used tear substitutes, i.e., CMC 0.5%, HPMC 0.3%, and hydroxypropyl-guar containing polyethylene glycol 400/propylene glycol (PEG/PG) in the treatment of patients with dry eye.
Methods
Medical records of all cases of clinically diagnosed dry eye attending the corneal clinic of Department of Ophthalmology, All India Institute of Medical Sciences, Bhopal, Madhya Pradesh, India, from July 2014 to June 2015, were reviewed. The protocol for this study was approved by the local Institutional Review Board/Ethical Committee. The study adhered to the tenets of the Declaration of Helsinki. Inclusion criteria for the study were cases with Ocular Surface Disease Index (OSDI) scoring[4] of >12 and cases in whom topical steroid in the form of loteprednol 0.5% and cyclosporine 0.05% was started along with topical lubricants. We excluded cases in whom only topical lubricants or either steroid or cyclosporine was prescribed, cases already on treatment for dry eye, cases in whom dry eye was secondary to some ocular or systemic disease, and patients with any concurrent disease or condition that could have complicated or interfered with the administration or evaluation of the study drug.
The OSDI is a validated questionnaire-based scoring system for diagnosis of dry eye.[5] It consists of 12 questions that provide a rapid assessment of the symptoms of ocular irritation and their impact on vision-related functions. The response to each item was scored from 0 (none of the time) to 4 (all of the time); an average score was generated and transformed into a scale of 0–100, with higher scores representing greater disability.[4,5,6]
For the purpose of analysis, the cases were categorized into three groups; Group-1 included cases prescribed CMC 0.5% four times a day (prepared at our compound pharmacy), Group-2 included cases prescribed with hydroxypropyl-guar containing PEG/PG (Systane Ultra, Novartis [India] Ltd.) twice a day, and Group-3 included cases prescribed with HPMC 0.3% (Genteal Eye Drops, Novartis [India] Ltd.). Details of demographic data such as age and sex were recorded. Parameters such as OSDI, tear film breakup time (TBUT), Schirmer test (ST), and slit-lamp examination findings were recorded at day 0 (before start of treatment), week 1, and week 4. Comparative analysis was done among different groups for improvement in OSDI scores, TBUT, and ST at each follow-up.
Statistical methods
The efficacy variables included TBUT, ST, and OSDI score. All variables were evaluated at days 0, 1 week, and 4 weeks. A repeated measures analysis of variance (ANOVA) was used to test for mean treatment group differences by day changes from baseline of TBUT, ST, and individual OSDI scores. ANOVA test was used to compare mean differences between treatment groups at day 0, week 1, week 4 in the OSDI score, TBUT, ST, and age characteristics. To find out which of the three drugs were most effective, post hoc test (Games–Howell) is applied which compares the drugs one by one. The Chi-square test was used to compare treatment group differences in demographic characteristics.
Results
One hundred and twenty patients were included in the study. Group 1 (CMC 0.5%), Group 2 (hydroxypropyl-guar containing PEG/PG), and Group 3 (HPMC 0.3%) included 41, 48, and 31 cases, respectively. Male patients accounted for 53.3% of the cases. The mean age in Group 1, Group 2, and Group 3 was 44.10 ± 17.82, 49.21 ± 15.31, and 42.58 ± 16.21 years, respectively. Demographic data were similar across treatment groups as shown in Table 1. The three groups were comparable in their baseline characteristics that included mean scores for OSDI (P = 0.462), mean TBUT (P = 0.172), and the mean scores for ST (P = 0.226) [Table 1]. Cases were divided into mild, moderate, and severe depending on the OSDI score (mild: 13–22 points, moderate: 23–32 points, and severe: 33–100 points).[7] There was no difference in severity between the three groups (P = 0.827) [Table 1].
Table 1.
Comparison of patients' baseline characteristics between Groups 1, 2, and 3*
Ocular Surface Disease Index
Mean OSDI in Group 1 was 30.14 ± 11.57 at week 1 and 25.78 ± 11.86 at week 4. Mean OSDI in Group 2 was 24.88 ± 9.66 at week 1 and 14.28 ± 6.83 at week 4. Mean OSDI in Group 3 was 28.86 ± 15.83 at week 1 and 17.98 ± 11.89 at week 4. Patients in Group 2 had a significantly lower mean OSDI score than those in Group 1 at week 1 (P = 0.000) and at week 4 (P = 0.000). Patients in Group 3 had a significantly lower mean OSDI score than those in Group 1 at week 1 (P = 0.001) and at week 4 (P = 0.000). Patients in Group 2 and Group 3 had no significant difference in mean OSDI score at week 1 (P = 0.541) and week 4 (P = 0.717). Change in OSDI at 1 week in Group 1 was 16.32%, in Group 2, it was 35.13%, and in Group 3, it was 31.5%. Change in OSDI at week 4 in Group 1 was 29.17%, in Group 2, it was 62.9%, and in Group 3, it was 57.3%.
Patients in Group 2 had a significantly better percentage change in OSDI than those in Group 1; at 0–1 week (P = 0.000), 0–4 weeks (P = 0.000), and 1–4 weeks (P = 0.000) [Table 2]. Patients in Group 3 had a significantly better percentage change in OSDI than those in Group 1, at 0–1 week (P = 0.000), 0–4 weeks (P = 0.000), and 1–4 weeks (P = 0.000). Patients in Group 2 and Group 3 had no significant difference in percentage change in OSDI at 0–1 week (P = 0.138), 0–4 weeks (P = 0.45), and 1–4 weeks (P = 0.113).
Table 2.
Comparison of percentage change in Ocular Protection Disease Index score between Groups 1, 2, and 3†
Tear breakup time
Mean TBUT in Group 1 was 9.20 ± 2.15 at week 1 and 9.57 ± 1.88 at week 4. Mean TBUT in Group 2 was 8.88 ± 2.33 at week 1 and 9.96 ± 1.64 at week 4. Mean TBUT in Group 3 was 8.88 ± 2.43 at week 1 and 9.85 ± 1.64 at week 4. Patients in Group 2 had a significant increase in mean TBUT than those in Group 1 at week 1 (P = 0.003) and at week 4 (P = 0.001). Patients in Group 3 had no significant difference in improvement in TBUT than those in Group 1 at week 1 (P = 0.06), but there was significant improvement of TBUT at week 4 (P = 0.014). There was no significant difference in improvement of TBUT in Group 2 and Group 3 at week 1 (P = 0.984) and at week 4 (P = 0.936).
Percentage change in TBUT among the three groups is summarized in Table 3. Patients in Group 2 had a significantly better percentage change in TBUT than those in Group 1; at 0–1 week (P = 0.016), 0–4 weeks (P = 0.006), and 1–4 weeks (P = 0.007). Patients in Group 3 had no significant difference in percentage change in TBUT than those in Group 1 at 0–1 weeks (P = 0.105), but there was a significant difference at 0–4 weeks (P = 0.032) and 1–4 weeks (P = 0.046). Patients in Group 2 and Group 3 had no significant difference in percentage change in TBUT from 0 to 1 week (P = 0.996), 0 to 4 weeks (P = 0.984), and 1 to 4 weeks (P = 0.982).
Table 3.
Comparison of percentage change in tear film breakup time between Groups 1, 2, and 3†
Shirmer's test
Mean ST in Group 1 was 25.78 ± 8.03 at week 1 and 26.06 ± 7.57 at week 4. Mean ST in Group 2 was 24.25 ± 8.37 at week 1 and 26.33 ± 6.67 at week 4. Mean ST in Group 3 was 23.72 ± 9.93 at week 1 and 25.46 ± 8.52 at week 4. Patients in Group 2 exhibited significant improvement in ST than Group 1 at week 1 (P = 0.018) and week 4 (P = 0.000). Patients in Group 3 exhibited significant improvement in ST than those i
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