Study Results
The study team has not published outcome measurements, participant flow, or safety data for this trial yet. Check back later for updates.
Basic Information
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COMPLETED
NA
90 participants
INTERVENTIONAL
2019-09-01
2019-11-30
Brief Summary
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Detailed Description
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Current knowledge about human corneal sensitivity is limited, as applied methods for ocular surface sensation measurement are limited with regards to reproducibility / accuracy.
Corneal sensitivity represents a neurological response from the free nerve endings within the epithelium. They are sensitive to mechanical, electrical, chemical or thermal stimuli and hence have a protective function for the cornea. Corneal nerves play an important role in cell growth and proliferation of epithelial cells, wound healing and repair. In experimental studies, corneal denervation has been reported to result in epithelial changes: increased permeability, decreased proliferation, changed appearance and delayed wound healing. Therefore, intact corneal innervation is required to maintain the integrity of a normal corneal epithelium. Corneal sensory nerves are believed to play an important role in maintaining the resting tear flow, as their afferent impulses from the ocular surface lead to a reflex response, best described by the lacrimal functional unit: an integrated system comprising the ocular surface tissues (cornea, corneal limbus, conjunctiva, conjunctival blood vessels, and eyelids), the tear secreting components (main and accessory lacrimal glands, meibomian glands, conjunctival goblet, and epithelial cells), and the sensory and motor nerves that connect them.
Current knowledge about ocular surface sensitivity is insufficient, as currently available measurement possibilities lack repeatability and accuracy. Before a new instrument can be developed, more research is required, in order to find a suitable concept for precise sensitivity measurement. For this purpose, two new different concepts with different / new stimulus types will be applied repeatably on healthy eyes in this study. The aim is to find out more about how corneal sensory fibres react to different types of stimuli (liquid / tactile / nylon thread) and how this can be consciously perceived by the individual. Is it possible to generate a stimulus that delivers a repeatable and reliable response within a useful stimulus force range which allows an interpretation / evaluation of normal / expected activity of superficial nerve fibres in the cornea? The study group will be divided into two age groups, as sensitivity changes are thought to occur in dependence of age. In vivo confocal microscopy has shown that the density of corneal nerve fibres in the sub-basal nerve plexus decreases with age, which consequently would suggest that sensitivity should also decrease. A very interesting research question is to find out, if such sensitivity differences can be detected with the nature of the stimuli applied in this study.
Conditions
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Keywords
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Study Design
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NON_RANDOMIZED
PARALLEL
BASIC_SCIENCE
NONE
Study Groups
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Group 'young age'
Group 'young age': 18 - 30 years of age; healthy eyes
Liquid Jet Esthesiometer Prototype
Balanced salt solution with a pH value similar to the tear film uesd as a liquid jet stimulus for corneal sensation threshold measurement
Tactile Esthesiometer Prototype
A round plastic nozzle (1.8mm diameter) used as a stimulus for corneal sensation threshold measurement
Cochet Bonnet esthesiometer
A nylon thread (0.12mm diameter) used as a stimulus for corneal sensation threshold measurement
Group 'advanced age'
Group 'advanced age': 50 - 70 years of age; healthy eyes
Liquid Jet Esthesiometer Prototype
Balanced salt solution with a pH value similar to the tear film uesd as a liquid jet stimulus for corneal sensation threshold measurement
Tactile Esthesiometer Prototype
A round plastic nozzle (1.8mm diameter) used as a stimulus for corneal sensation threshold measurement
Cochet Bonnet esthesiometer
A nylon thread (0.12mm diameter) used as a stimulus for corneal sensation threshold measurement
Interventions
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Liquid Jet Esthesiometer Prototype
Balanced salt solution with a pH value similar to the tear film uesd as a liquid jet stimulus for corneal sensation threshold measurement
Tactile Esthesiometer Prototype
A round plastic nozzle (1.8mm diameter) used as a stimulus for corneal sensation threshold measurement
Cochet Bonnet esthesiometer
A nylon thread (0.12mm diameter) used as a stimulus for corneal sensation threshold measurement
Eligibility Criteria
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Inclusion Criteria
* Group 'advanced age': 50 - 70 years of age; healthy eyes with Ocular Surface Disease Index Score \</= 13
Exclusion Criteria
* Injury and history of operations on the anterior segment of the eye
* regular application of systemic or ocular medication known to affect the tear film, specifically on the day of measurement
* rigid gas permeable contact lens wear
* soft contact lens wear less than 48 hours before study visit
18 Years
70 Years
ALL
Yes
Sponsors
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Daniela Nosch
OTHER
Responsible Party
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Daniela Nosch
Clinical Professor
Locations
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Institute of Optometry, FHNW
Olten, Canton of Solothurn, Switzerland
Countries
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References
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Nosch DS, Kaser E, Bracher T, Joos RE. Clinical application of the Swiss Liquid Jet Aesthesiometer for corneal sensitivity measurement. Clin Exp Optom. 2024 Jan;107(1):14-22. doi: 10.1080/08164622.2023.2191782. Epub 2023 Apr 5.
Other Identifiers
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2019-01252
Identifier Type: -
Identifier Source: org_study_id