Clinical characteristics of corneal hyperalgesia in patients with dry eye symptoms

Abstract

Purpose: We analyzed the clinical characteristics of corneal hyperalgesia patients with dry eye symptoms. Methods: Sixty-nine eyes of 69 adults (aged ≥ 20 years) who visited the hospital due to dry eye symptoms were analyzed. Using a Cochet-Bonnet esthesiometer, patients with ≥ 40 mm corneal sensitivity were designated as the corneal hyperalgesia group, and those with < 40 mm were designated as the control group. All patients were tested by slit lamp biomicroscopy. The tear film break-up time (TFBUT), tear secretion, meibography, tear lipid layer thickness, eye blink pattern and Ocular Surface Disease Index were assessed. The eye blink pattern was divided into four types, flat, uphill, downhill, and mixed, and the rate of partial eye blink was recorded. Results: We compared the 38 eyes in the corneal hyperalgesia group with the 31 eyes in the control group. The pain sensitivity was 51.18 ± 7.66 and 21.61 ± 9.25 mm in the corneal hyperalgesia and control groups, respectively. Tactile sensitivity was higher in the hyperalgesia group (59.21 ± 1.85 mm) than the control group (54.84 ± 10.12 mm) (p = 0.048), and the TFBUT in the hyperalgesia group (3.47 ± 0.80 seconds) was significantly shorter than the control group (4.10 ± 1.16 seconds) (p = 0.036). There was a significant difference in the proportions of the four eye blink patterns between the hyperalgesia and control groups (p = 0.023). In the hyperalgesia group, 35.1% were uphill types and 32.4% were flat types, while in the control group, 43.8% were downhill types. The other tests showed no significant group differences. Conclusions: The TFBUT was shorter in patients with dry eye symptoms than controls, and the proportions of the four eye blink patterns also differed between the groups. © 2021 The Korean Ophthalmological Society