Clinical trial NCT04804592: Investigation in Corneal Sensation and Contact Lens Wear
Official title: Investigation in Variability and Repeatability of Corneal Sensation in a Normal Population and Contact Lens Wearers
Study type: INTERVENTIONAL
Overall status: COMPLETED
Phase: NA
Conditions: Cornea
Sense Loss; Cornea
Keywords: cornea
ocular surface sensation
corneal sensitivity
contact lens wear
Lead sponsor: University of Applied Sciences and Arts Northwestern Switzerland
Sponsor class: OTHER
First posted: 2021-03-18
Enrollment: 111
Sex: ALL
Minimum age (years): 18
Maximum age (years): 50
Standard ages: ADULT
Accepts healthy volunteers: yes
Allocation: NON_RANDOMIZED
Intervention model: PARALLEL
Primary purpose: BASIC_SCIENCE

Brief summary: 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 three groups of individuals: two groups with different types of contact lenses (CL) and one without CL, as sensitivity changes are thought to occur with CL wear. 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.

Detailed description: The aim of this study is to gain more physiological knowledge about ocular surface sensation (corneal sensitivity), with application of three different concepts employing different types of stimuli for triggering a response from the pain sensitive nerve endings in the superficial cornea: 1) tactile method: a round plastic nozzle (2 mm diameter) is applied to the ocular surface with a defined, low force for a duration of 100ms. 2) liquid jet method: a liquid jet (isotonic saline) of a temperature to match ocular surface temperature is applied to the ocular surface with low pressure and low volume, from a distance of 15 mm.3) commercially available Cochet Bonnet esthesiometer (nylon thread). The study group will be divided into three groups of individuals: two groups with different types of contact lenses (CL) and one without CL, as sensitivity changes are thought to occur with CL wear. 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.

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 three groups of individuals: two groups with different types of contact lenses (CL) and one without CL, as sensitivity changes are thought to occur with CL wear.

Eligibility criteria: Inclusion Criteria:

Group A:

Silicone hydrogel (SiHy) CL wear at least 3 days per week and at least 8 hours per day; 18 - 50 years of age; healthy eyes with OSDI \</= 13

Group B:

Rigid gas permeable (RGP) CL wear at least 3 days per week and at least 8 hours per day; 18 - 50 years of age; healthy eyes with OSDI \</= 13

Group C:

No current CL wear for at least 3 months; 18 - 50 years of age; healthy eyes with OSDI \</= 13

Exclusion Criteria:

* Systemic disease that may affect ocular health, such as diabetes
* 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

Primary outcomes:
measure: Repeatability of mechanical corneal sensation thresholds with the liquid jet protoype esthesiometer
timeFrame: two weeks
measure: Repeatability of mechanical corneal sensation thresholds with the tactile prototype esthesiometer
timeFrame: two weeks
measure: Repeatability of mechanical corneal sensation thresholds with the Cochet Bonnet esthesiometer
timeFrame: two weeks
Secondary outcomes:
measure: Correlation between corneal sensation thresholds with the Cochet Bonnet esthesiometer
timeFrame: one day
measure: Correlation between corneal sensation thresholds with the liquid jet prototype esthesiometer
timeFrame: one day
measure: Correlation between corneal sensation thresholds with the tactile prototype esthesiometer
timeFrame: one day
measure: Comparison of corneal sensation thresholds, obtained with the Cochet Bonnet esthesiometer, between the three groups in the study population
timeFrame: two weeks
measure: Comparison of corneal sensation thresholds, obtained with the liquid jet prototype esthesiometer, between the three groups in the study population
timeFrame: two weeks
measure: Comparison of corneal sensation thresholds, obtained with the tactile prototype esthesiometer, between the three groups in the study population
timeFrame: two weeks
Other outcomes:
Locations:
city: Olten
country: Switzerland
facility: Institute of Optometry, FHNW
state: Solothurn
Study officials:
affiliation: University of Applied Sciences and Arts Northwestern Switzerland FHNW
name: Daniela S Nosch, PhD
role: PRINCIPAL_INVESTIGATOR
References:
citation: Belmonte C, Acosta MC, Gallar J. Neural basis of sensation in intact and injured corneas. Exp Eye Res. 2004 Mar;78(3):513-25. doi: 10.1016/j.exer.2003.09.023.
citation: Bergenske PD, Polse KA. The effect of rigid gas permeable lenses on corneal sensitivity. J Am Optom Assoc. 1987 Mar;58(3):212-5.
citation: Knoll HA, Williams J. Effects of hydrophilic contact lenses on corneal sensitivity. Am J Optom Arch Am Acad Optom. 1970 Jul;47(7):561-3. doi: 10.1097/00006324-197007000-00007. No abstract available.
citation: Millodot M. Does the long term wear of contact lenses produce a loss of corneal sensitivity? Experientia. 1977 Nov 15;33(11):1475-6. doi: 10.1007/BF01918817.
citation: Muller LJ, Marfurt CF, Kruse F, Tervo TM. Corneal nerves: structure, contents and function. Exp Eye Res. 2003 May;76(5):521-42. doi: 10.1016/s0014-4835(03)00050-2.
citation: Golebiowski B, Chao C, Stapleton F, Jalbert I. Corneal Nerve Morphology, Sensitivity, and Tear Neuropeptides in Contact Lens Wear. Optom Vis Sci. 2017 Apr;94(4):534-542. doi: 10.1097/OPX.0000000000001063.
citation: Stapleton F, Chao C, Golebiowski B. Topical Review: Effects of Contact Lens Wear on Corneal, Conjunctival, and Lid Margin Sensitivity. Optom Vis Sci. 2019 Oct;96(10):790-801. doi: 10.1097/OPX.0000000000001429.
citation: Golebiowski B, Papas EB, Stapleton F. Factors affecting corneal and conjunctival sensitivity measurement. Optom Vis Sci. 2008 Apr;85(4):241-6. doi: 10.1097/OPX.0b013e3181694f96.
citation: Stapleton F, Golebiowski B, Skotnitsky C, Tan ME, Holden BA. Corneal and conjunctival sensitivity in intolerant contact lens wearers. J Optom. 2015 Jan-Mar;8(1):62-3. doi: 10.1016/j.optom.2014.05.004. Epub 2014 Jun 7. No abstract available.
citation: Golebiowski B, Papas EB, Stapleton F. Corneal and conjunctival sensory function: the impact on ocular surface sensitivity of change from low to high oxygen transmissibility contact lenses. Invest Ophthalmol Vis Sci. 2012 Mar 9;53(3):1177-81. doi: 10.1167/iovs.11-8416.