Capsaicin-induced pain sensitivity in short tear break-up time dry eye

Minako Kaido; Sachiko Inoue; Motoko Kawashima; Reiko Ishida; Shigeru Nakamura; Kazuo Tsubota

doi:10.1016/j.jtos.2020.07.008

Capsaicin-induced pain sensitivity in short tear break-up time dry eye

Ocul Surf. 2020 Oct;18(4):620-626. doi: 10.1016/j.jtos.2020.07.008. Epub 2020 Jul 24.

Authors

Minako Kaido¹, Sachiko Inoue², Motoko Kawashima³, Reiko Ishida⁴, Shigeru Nakamura³, Kazuo Tsubota⁵

Affiliations

¹ Department of Ophthalmology, Keio University School of Medicine, Tokyo, Japan; Wada Eye Clinic, Chiba, Japan; Ishida Eye Clinic, Shizuoka, Japan. Electronic address: tomoulton777@ff.em-net.ne.jp.
² Department of Ophthalmology, Keio University School of Medicine, Tokyo, Japan; Haneginomori Eye Clinic, Tokyo, Japan.
³ Department of Ophthalmology, Keio University School of Medicine, Tokyo, Japan.
⁴ Department of Ophthalmology, Keio University School of Medicine, Tokyo, Japan; Ishida Eye Clinic, Shizuoka, Japan.
⁵ Department of Ophthalmology, Keio University School of Medicine, Tokyo, Japan; Tsubota Laboratory Inc., Tokyo, Japan.

PMID: 32712260
DOI: 10.1016/j.jtos.2020.07.008

Abstract

Purpose: To evaluate transient receptor potential vanilloid 1 (TRPV1)-mediated pain sensitivity in patients with short tear break-up time (TBUT) dry eye (DE) by using the capsaicin stimulus test.

Methods: This prospective cross-sectional comparative study included 22 eyes of 22 patients with short TBUT DE and 11 eyes of 11 non-DE control subjects. Patients were divided into two groups based on response to standard DE treatments: 10 non-responders (intractable DE) and 12 responders (responsive DE). Mechanical touch (M-touch) and mechanical pain (M-pain) were measured using a Cochet-Bonnet esthesiometer. Capsaicin-induced pain (C-pain) and C-pain duration (C-pain DT) were measured using a capsaicin stimulus test. Psychological distress was also assessed.

Results: M-touch sensitivity was similar among all three groups. M-pain sensitivity was higher in the responsive DE group than in the intractable DE and control groups (P < .001). C-pain sensitivity was lower (P < .001) in the intractable DE group than in the responsive DE and control groups, and C-pain DT was shorter (P = .006) in the intractable DE group than in the responsive DE group. Psychological distress was higher in the intractable DE group than in the control group (P < .001).

Conclusions: Patients with intractable short TBUT DE were less sensitive to the effects of capsaicin than patients with responsive short TBUT DE and controls. Altered neural activation may contribute to the development of DE symptoms in the short TBUT DE subjects. The capsaicin stimulus test may be used to better understand pain sensitivity in short TBUT DE patients.

Keywords: Capsaicin; Depression; Dry eye; Pain sensitivity; TRPV1; Tear break up time.

MeSH terms

Capsaicin / adverse effects*
Cross-Sectional Studies
Dry Eye Syndromes* / chemically induced
Humans
Pain / chemically induced*
Prospective Studies
Tears

Substances

Capsaicin