Comparing preserved and preservative-free artificial tear drops on tear film stability and flow rate in dry eye

Aim: To compare the effect of preservative-containing artificial tears and preservative-free artificial tears on tear film stability among adults with dry eye syndrome. Methods: A randomized controlled trial was conducted on 80 participants (40 females and 40 males), aged 19 to 69 years, who were randomly selected after completing the Ocular Surface Disease Index (OSDI) questionnaire, with only those with OSDI scores of 13 and above included in the study. Participants were divided into two groups. One group received artificial tears containing 0.3% hydroxypropyl methylcellulose preserved with 0.01% benzalkonium chloride (Hypromellose eye drops, manufactured by Martindale Pharmaceuticals), and the other group received preservative-free artificial tears containing 0.5% carboxymethylcellulose sodium and 0.9% glycerin (Refresh eye drops, manufactured by AbbVie). Each participant was instructed to instill one drop in each eye, four times daily, for four weeks. Tear film stability, measured using Tear Break-Up Time (TBUT), and Tear Flow Rate assessed with Schirmer’s test, were recorded for each participant before and after the application of the respective artificial tear eye drops. Paired T-test and one-way ANOVA were employed to analyze data using the Statistical Package for Social Sciences (SSPS version 22.0) Results: Both groups showed statistically significant increases in tear film stability and tear flow rate post-treatment, as evidenced by paired T-tests (p < 0.05). However, the comparison using ANOVA indicated no significant differences in the tear film stability and tear flow rate after four weeks (p > 0.05). Conclusion: There was no notable difference between preservative-containing artificial tears eye drops and preservative-free artificial tears eye drops on tear film stability and tear flow rate, therefore clinicians can confidently recommend both non-preservative-free and preservative-free artificial tears as effective management options for dry eye.