To demonstrate the effects of prolonged silent reading on tear film and ocular surface parameters, researchers from Johns Hopkins University evaluated 177 patients with dry eye (DE) and 34 healthy patients. The team found that quantifying DE after having patients perform visually straining activities, such as prolonged silent reading, may help researchers better understand patient symptomatology. They add that evaluating tear film and ocular surface parameters at rest may cause researchers to miss clinical findings brought about by common everyday tasks, leading to discordance between patient-reported symptoms and clinician-observed signs.

In this prospective observational clinical study, the Maryland researchers first evaluated patient symptoms using the Ocular Surface Disease Index (OSDI) questionnaire. They then performed a series of five tests—automated noninvasive tear break-up time (TBUT), surface asymmetry and regularity indices, Schirmer's testing without anesthesia, corneal staining using fluorescein and conjunctival staining using lissamine green—both before and after patients read a 30-minute validated passage silently.

The team observed that all parameters, with the exception of surface asymmetry index, worsened after the reading task in all patients. They note that the worsening was statistically significant for corneal and conjunctival staining in the DE group and for corneal staining in the control group.

At baseline, the team found that OSDI scores correlated only with corneal and conjunctival staining scores, and among postreading measurements, with TBUT and corneal and conjunctival staining. They note that changes in TBUT and Schirmer's test correlated significantly with their respective baseline values, indicating that the more unstable the tear film and the lower the aqueous tear secretion, the worse they become after the prolonged reading task. They add that worsening in corneal staining directly correlated with the baseline conjunctival staining and surface regularity index.

Karakus S, Agrawal D, Hindman HB, et al. Effects of prolonged reading on dry eye. Ophthalmology. 2018;125(10):1500-5.