Soft lens lubricants and prelens tear film stability

Soft contact lens wearers complaining of "dry eye" are frequently prescribed rewetting drops, although the mode of action and efficacy of this treatment have not been established. Enhancement of prelens tear film (PLTF) stability could provide a basis for symptomatic relief with solution instillation. Thirty symptomatic hydroxyethyl methacrylate (HEMA) lens wearers participated in 4 separate trials of no solution (baseline), saline, and 2 soft lens lubricants. Solutions were applied for a 6-h adaptation period, and PLTF noninvasive break-up time (NIBUT) was monitored for 1 h after a final instillation. PLTF NIBUT was significantly elevated 1 min after instillation of all solutions (p less than 0.001, logrank test) but this effect persisted for less than 5 min. The transient enhancement of PLTF stability arising from the instillation of these rewetting solutions is unlikely to provide a basis for prolonged symptomatic relief.