To prospectively evaluate the effect of benzalkonium chloride (BAK)-preserved latanoprost on ocular surface damage and identify the associated risk factors among treatment-naive glaucoma patients.
The basal Schirmer’s test results, corneal Oxford staining score, non-invasive keratograph tear-breakup time, oculus hyperemia index score (objective metrics), and ocular surface disease index (OSDI) questionnaire (subjective metric) were evaluated at baseline, 1 month, and 4 months after receiving latanoprost eye drops. Associated risk factors were assessed by multivariate linear regression.
Seventy-four eyes (44 patients) were enrolled. Basal Schirmer’s test tear-flow and Oxford scores gradually deteriorated (β = -0.14, P = 0.001 and β = 0.1, P < 0.001, respectively). The percentage of unstable tear-film (breakup time < 10 s) increased significantly at 4 months (6.21% vs 9.11%, P = 0.042). Hyperemic scores increased significantly at 1 month and normalized at 4 months (P = 0.01 and P = 0.16, respectively); total OSDI scores tended to improve (β = -0.76, P = 0.06). Older age was associated with additional corneal Oxford staining (P = 0.005); female sex was associated with increased unstable tear-film scores (P = 0.01). Artificial tear use was associated with a smaller decrease in basal Schirmer's test values (P = 0.01) and a smaller increase in unstable tear-film scores (P = 0.02).
Preserved latanoprost eye drops affected ocular surface changes in glaucoma patients through decreased basal tear secretion. Artificial tears represent an early intervention in vulnerable glaucoma patients with reduced tear secretion and impaired tear-film stability.

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