Comparative Effectiveness of Artificial Tears With and Without Preservatives in Patients With Dry Eye Disease: A Randomized Clinical Trial

Dry Eye Disease (DED) is a common, chronic ocular surface disorder characterized by tear film instability, ocular discomfort, and visual disturbance. Artificial tears are the first-line treatment for DED; however, many formulations contain preservatives such as benzalkonium chloride (BAK) and stabilized oxychloro complex (SOC) which may cause ocular surface toxicity with long-term use. Preservative-free artificial tears are considered safer alternatives, but comparative clinical evidence from Nepal is limited. This study aims to compare the clinical efficacy and safety of preservative-free versus preserved carboxymethylcellulose (CMC) artificial tears in patients with Dry Eye Disease. This will be a hospital-based, randomized, double-blinded controlled clinical trial conducted in the ophthalmology outpatient department of a tertiary care hospital in Nepal. A total of 80 adult patients diagnosed with Dry Eye Disease will be enrolled and randomly allocated in a 1:1 ratio to receive either preservative-free CMC artificial tears or preserved CMC artificial tears for a duration of eight weeks. Participant, investigators, outcome assessors and data analysts will remain blinded to minimize assessment bias. Baseline assessments will include the Ocular Surface Disease Index (OSDI) questionnaire, Tear Film Break-Up Time (TBUT), Schirmer's test (without anesthesia), and corneal fluorescein staining. These outcomes will be reassessed at four and eight weeks. Safety and tolerability will be evaluated by documenting patient-reported adverse effects. Data will be analyzed using appropriate statistical methods, with a p-value of less than 0.05 considered statistically significant. The study is expected to demonstrate superior safety and improved ocular surface outcomes with preservative-free artificial tears compared to preserved formulations. Findings from this research will provide local evidence to guide rational prescribing practices and improve the management of Dry Eye Disease in Nepal.