Patients with tear dysfunction may not experience a decrease in blink rate, according to a study in Eye & Contact Lens that used video display viewing (VDV). a decrease has been observed in normal eyes. researchers compared blink rates during conversation and VDV and correlated them with signs and symptoms of dry eye. They note that previous studies have observed decreased blink rates during VDV, although a lack of comprehensive data exists on blink rates in those with tear dysfunction.
The study measured blink rate in 18 patients in a control group and in those with tear dysfunction using an infrared blink sensor while watching a video and also during conversation. Participants with meibomian gland dysfunction (MGD, n=23), conjunctivochalasis (CCH, n=19) and aqueous tear deficiency (n=52) were included in the tear dysfunction group. Participants also completed questionnaires assessing irritation frequency, severity and blink frequency as well as an ocular surface evaluation.
The study found that blink rates for both conversation and VDV were significantly higher for the CCH and aqueous tear deficiency groups than for the control group (P ≤.005). Additionally, in the control group, the VDV blink rate was significantly lower than the conversation blink rate (P =.006), although this difference was not observed in the tear dysfunction groups. Finally, all tear dysfunction groups self-reported higher blink frequency overall than the control group, and blink rates for both activities had a significant correspondence with irritation frequency and severity.
The study explains that, for patients with tear dysfunction, increased blink rate may disrupt function and quality of life, and that it should be explored further as it is a common complaint among this cohort.
“The greater blink rate while video viewing in eyes with tear dysfunction may be compensatory to maintain quality vision or comfort because of tear instability or irritation symptoms,” the research says. “Many office workers spend most of their day viewing a video display. Tear dysfunction in these individuals could cause more frequent or forceful blinking that could place greater frictional stress on the ocular surface, worsening irritation and fatigue, and amplifying severity of ocular surface epithelial disease.”
Mitchell T, Murri M, Pflugfelder S. Video viewing blink rate in normal and dry eyes. Eye & Contact Lens. Published online April 20, 2021. doi:10.1097/ICL.0000000000000791.