Noninvasive, Objective, Multimodal Tear Dynamics Evaluation of 5 Over-the-Counter Tear Drops in a Randomized Controlled Trial

Abstract

To assess the ability of a noninvasive, objective, multimodal system to compare the efficacy and optical quality of 4 different groups of 5 over-the-counter tear drops. Wavefront sensing and optical coherence tomography (OCT) were used to objectively assess visual quality and tear volume, respectively, after the over-the-counter tear drops [2 polyethylene glycol (PEG)-400, 1 carboxymethyl cellulose (CMC), 1 polyvinyl alcohol/PEG-400 (PVA), and 1 glycerine/polysorbate-80] were administered to 23 patients with aqueous-deficient dry eye in a randomized, controlled, double-masked trial. Measurements at each of the 5 visits were taken from both eyes at baseline and 5, 20, and 40 minutes after drop instillation. At 5 minutes after drop instillation, the 2 PEG drops showed significant worsening of visual quality (-128.87%, P = 0.001) compared with CMC, PVA, and glycerine drops. Tear volume was elevated significantly with PEG and CMC drops at 5 minutes (+33.2%, P = 0.002; +29.9%, P < 0.001) compared with the other groups. Subjects with a Schirmer score of less than 5 mm at 5 minutes showed improvement in visual quality with PEG drops, whereas those with a fluorescein staining score of 1 to 2 showed improvement with both PEG and CMC drops. A trend toward decreasing visual quality with increasing tear meniscus was noted. Noninvasive multimodal imaging has the potential to evaluate tear dynamics and the efficacy of artificial tears objectively. Certain artificial tear components and the temporary increase in tear volume after instillation of artificial tears may contribute to transient reduction of visual quality.