Considering that tears play the role of a lubricant, it is speculated that in the pathophysiology of dry eye, increased friction during blinking results in corneal and conjunctival damage, which may subsequently affect the blink. The purpose of this study was to investigate the relationship between ocular surface epithelial damage, tear abnormalities, and blinks in patients with dry eye.
This study involved 45 eyes of 45 female patients with dry eye (mean age: 57.6 years). In all eyes, tear meniscus radius (mm), spread grade of the tear film lipid layer (SG: 1-5: 1 being the best), fluorescein breakup time (FBUT, seconds), corneal and bulbar conjunctival epithelial damage (CED: 15 points maximum and CONJUNCTIVAL EPITHELIAL DAMAGE (CjED): 6 points maximum, respectively), and Schirmer I test (ST1, mm) were evaluated. Blink rate (BR, blinks per minute), palpebral aperture height (mm), upper-eyelid opening-phase amplitude/upper-eyelid closing-phase amplitude (mm), upper-eyelid opening-phase duration/upper-eyelid closing-phase duration (ms), and upper-eyelid opening-phase maximum velocity/upper-eyelid closing-phase maximum velocity (mm/s) were measured using a custom-made high-speed blink analyzer. Finally, the factors that determine CED and CjED were investigated by multiple regression analysis, in which the parameters were chosen using the stepwise procedure.
CED and CjED were found to be described as 2.687 + (1.816 × SG) − (0.937 × FBUT) (R2 = 0.656, P < 0.0001) and 0.684 + (0.801 × SG) − (0.526 × FBUT) − (0.041 × ST1) + (0.010 × upper-eyelid closing-phase maximum velocity) (R2 = 0.714, P < 0.0001), respectively.
Although CED was significantly related to only tear abnormalities, CjED was significantly related to tear abnormalities and blinking.
*Department of Ophthalmology, Kyoto Prefectural University of Medicine, Kyoto, Japan; and
†Frontier Medical Science and Technology for Ophthalmology, Kyoto Prefectural University of Medicine, Kyoto, Japan.
Correspondence: Norihiko Yokoi, MD, PhD, Department of Ophthalmology, Kyoto Prefectural University of Medicine, 465 Kajii-cho, Hirokoji-agaru, Kawaramachi-dori, Kamigyo-ku, Kyoto 602-0841, Japan (e-mail: firstname.lastname@example.org).
Supported in part by Grants-in-Aid for scientific research from the Japanese Ministry of Education, Culture, Sports, Science and Technology (grant number: 16K11269).
N. Yokoi is a consultant for Rohto Co Ltd. S. Kinoshita is a consultant for Santen Pharmaceutical Co Ltd and Otsuka Pharmaceutical Co Ltd. The remaining authors have no conflicts of interest to disclose.
Received August 01, 2018
Accepted November 09, 2018