Randomized Single-Masked Study of Preservative-Free Versus Preserved Hyaluronic Acid in Dry Eye Disease.

In 30 seconds

This randomized, single-masked, 6-month trial compared preservative-free hyaluronic acid (PF HA) with benzalkonium chloride-preserved hyaluronic acid (BAK HA) in 47 patients with dry eye disease; 43 completed the study. Both formulations improved signs and symptoms, but PF HA produced a greater reduction in Ocular Surface Disease Index (OSDI) score at month 6: adjusted change, -14.36 vs. -9.42 (P = 0.001). About 40% of PF HA-treated patients had normal OSDI scores at the final visit, compared with none receiving BAK HA. Several signs showed more favorable longitudinal changes with PF HA, although final-visit between-group differences in signs were not significant.

Key findings

• OSDI improvement at month 6 was greater with PF HA than BAK HA (adjusted change, -14.36 vs. -9.42; P = 0.001).
• Approximately 40% of PF HA-treated patients achieved normal OSDI scores at the final visit, compared with none in the BAK HA group.
• Longitudinal changes favored PF HA for OSDI (P < 0.001), NIBUT (P = 0.017), FCS (P = 0.002), and LCS (P < 0.001).
• PF HA was associated with lower instillation frequency (P < 0.001); no significant between-group differences in several signs were observed at the final visit.

Why it matters

The comparison isolates preservative content by using otherwise identical formulations, and suggests that preservative-free hyaluronic acid may provide greater symptom relief over six months. The distinction between symptom improvement and final-visit objective signs is clinically relevant when interpreting treatment response: the symptom advantage was clearer than differences in several measured ocular-surface outcomes.

What to keep in mind

The trial was small, with 47 patients randomized and 43 completing follow-up, and was single-masked. Several objective signs did not differ significantly between groups at the final visit.