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Using synthesized onion lachrymatory factor to measure age-related decreases in reflex-tear secretion and
Hisayo Higashihara1, Norihiko Yokoi, Morihiro Aoyagi
1Department of Ophthalmology, Kyoto Prefectural University of Medicine, Kyoto, Japan.
Purpose:
To use synthesized onion lachrymatory factor (SOLF) to investigate age-related changes in reflex-tear secretion and ocular-surface sensation.
Methods:
We separated 91 healthy volunteers into four groups: groups A, age 20-29 years; B, 30-39; C, 40-49; and D, older than 50 years. We exposed one eye of each subject to SOLF and measured the elapsed time until the subject's limit of irritation tolerance (TLI) was reached and an increase in the tear meniscus radius (DeltaR). After the SOLF stimulus, corneal sensitivity was examined by Cochet-Bonnet esthesiometry (CB), and reflex-tear secretion was examined by the Schirmer I-test (ST).
Results:
TLI was significantly shorter in group A than in the other groups (P < 0.0001), and the groups B and D also differed significantly from each other (P = 0.0013). The increase in DeltaR was significantly greater in group A than in group C (P = 0.0306) or D (P < 0.0001), and groups B (P = 0.0002) and C (P = 0.0308) also differed significantly from group D. There were no significant intergroup differences in the CB and ST results.
Conclusions:
An age-related decrease in reflex-tear secretion and ocular-surface sensation was revealed by the SOLF test but could not be detected by either CB or the ST.
Insights
Synthesized onion lachrymatory factor (SOLF) revealed age-related declines in tear secretion and ocular sensation. Standard tests like Cochet-Bonnet esthesiometry and Schirmer I-test did not detect these changes.
Area of Science:
- Ophthalmology
- Neuroscience
- Gerontology
Background:
- Ocular surface sensation and tear secretion are crucial for maintaining eye health.
- Age-related changes can impact these functions, potentially leading to discomfort and visual disturbances.
- Existing diagnostic methods may not fully capture subtle age-related alterations.
Purpose of the Study:
- To evaluate age-related differences in reflex tear secretion and ocular surface sensation using synthesized onion lachrymatory factor (SOLF).
- To compare the efficacy of SOLF testing with conventional methods like Cochet-Bonnet esthesiometry and Schirmer I-test in detecting age-related changes.
Main Methods:
- Ninety-one healthy volunteers were stratified into four age groups (20-29, 30-39, 40-49, and >50 years).
- Subjects were exposed to SOLF, measuring limit of irritation tolerance (TLI) and tear meniscus radius increase (DeltaR).
- Corneal sensitivity (Cochet-Bonnet) and reflex tear secretion (Schirmer I-test) were assessed post-stimulus.
Main Results:
- SOLF testing showed a significantly shorter TLI in younger adults compared to older groups.
- A significantly greater DeltaR was observed in the youngest group compared to older groups.
- No significant differences in corneal sensitivity or Schirmer I-test results were found across age groups.
Conclusions:
- SOLF effectively identified age-related decreases in reflex tear secretion and ocular surface sensation.
- Conventional tests (Cochet-Bonnet, Schirmer I-test) were less sensitive in detecting these age-related changes.
- SOLF represents a promising tool for assessing age-related functional decline in the ocular system.
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