Sustained gazing causes decline in visual function of dry eye patients
Sustained gazing has a negative impact on visual performance in dry eye patients, according to a recent study published in the American Journal of Ophthalmology.
“Visual disturbance caused by dry eye can interfere with many everyday activities. Patients with dry eye frequently complain of difficulty with visual tasks that require sustained gazing ... even when they have perfect visual acuity,” Esen K. Akpek, MD, Wilmer Eye Institute, and colleagues wrote. “This study sought to quantify the impact of sustained gazing on visual performance in patients with dry eye.”
In a prospective, comparative study, researchers evaluated 176 patients with dry eye and 33 control participants during a sustained gazing task for dry eye symptomology. Out-loud word per minute (wpm) reading speed and reading duration was measured, followed by a 30-minute silent reading session. No difference was found between the dry eye patients and control participants regarding reading speed (172 wpm vs. 180 wpm, respectively) or time to read the excerpt (33 seconds vs. 30 seconds) at baseline.
Study results showed a decrease in reading speed (161 wpm at baseline vs. 172 wpm; P = .002) and increase in reading duration in the dry eye group, compared with baseline measurements (30 seconds at baseline vs. 33 seconds; P .001); control participants saw no change (P > .05). Following sustained gazing, investigators observed differences in both the dry eye group and control group (161 wpm vs. 188 wpm, respectively; P = .006; and 38 seconds vs. 31 seconds, respectively; P = .003). Dry eye symptomology measurements showed corneal staining was associated with decreases in reading speed with each 1-point increase in staining score leading to a 5-wpm reduction (95% CI, –8 to –1; P = .01).
“This study was able to quantify the negative impact of sustained gazing through prolonged silent reading on vision in patients with dry eye,” Akpek and colleagues concluded. “The present authors propose prolonged silent reading as a relevant test and corneal fluorescein staining as a surrogate for vision-related quality of life.”
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Statistics show that dry eye can affect upward of 30% of the population older than 50 years. One of the predominant symptoms these patients experience relates to difficulty with visual tasks, especially during episodes of sustained gazing that may include tasks as routine as reading, driving or computer use. For the purposes of this study, however, sustained gazing is defined as a 30-minute period of silent reading.
The authors’ goal in this comparative before-and-after study was to evaluate the effects of sustained gazing on visual function in patients with dry eye. Perhaps as expected, those participants with dry eye experienced a significant decrease in reading speed compared with the control participants. Further, alterations in the tear film ultimately led to an increase in corneal staining, resulting in the negative impact on visual performance.
Because routine ocular examinations fail to accurately measure functional vision in patients with dry eye, this study proposes that prolonged silent reading and corneal fluorescein staining could act as a metric to determine the impact of dry eye on the vision-related quality of life in these patients.
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