A word of caution for your dry eye patients who can’t keep their noses out of a book: sustained gazing—from activities such as silent reading—may negatively impact their visual performance, according to a study in the American Journal of Ophthalmology.

Researchers from the Wilmer Eye Institute found little difference in reading speeds between dry eye patients and a control group when both were at rest. However, investigators observed a decreased reading speed in dry eye patients following a period of sustained gazing, which they correlated to corneal staining severity at baseline.

The study included 176 patients with dry eye and 33 controls. All participants were aged 50 or older. The investigators assessed dry eye symptoms and clinical parameters and measured subjects’ out-loud reading speed using the International Reading Speed Test (IReST) based on words per minute. Subjects then read a different excerpt and were tested again following 30 minutes of silent reading.

At baseline, dry eye patients and controls had about the same reading speeds (172 wpm vs. 180 wpm, respectively) and took approximately the same amount of time to read the excerpt (33 seconds vs. 30 seconds, respectively). However, after silent reading, the dry eye patients had a decrease in their reading speed and an increase in the length of time it took them to read the passage compared with the first test (161wpm vs. 172wpm, 38 seconds vs. 33 seconds, respectively). The controls’ results were about the same in both tests, the study noted.

 Comparing the results after sustained reading, the researchers also found major differences between the two groups: 161wpm for the controls vs. 188wpm for the dry eye group, and 38 seconds vs. 31 seconds for the control and dry eye groups, respectively. Additionally, each one-point increase in the baseline corneal staining score was tied to a 5wpm reduction in reading speed.