Investigation in Corneal Sensation and Contact Lens Wear

Investigation in Variability and Repeatability of Corneal Sensation in a Normal Population and Contact Lens Wearers

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.

Study Overview

• Status: Completed
• Conditions: Cornea; Sense Loss; Cornea
• Intervention / Treatment: Device: Liquid Jet Esthesiometer Prototype; Device: Tactile Esthesiometer Prototype; Device: Cochet Bonnet esthesiometer

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.

• Study Type: Interventional
• Enrollment (Actual): 111
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Switzerland
  • Solothurn
    • Olten, Solothurn, Switzerland, 4600
      • Institute of Optometry, FHNW

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 50 years (ADULT)
• Accepts Healthy Volunteers: Yes
• Genders Eligible for Study: All

Description

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

Study Plan

How is the study designed?

Design Details

• Primary Purpose: BASIC_SCIENCE
• Allocation: NON_RANDOMIZED
• Interventional Model: PARALLEL
• Masking: NONE

Number of Arms

3

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
EXPERIMENTAL: Group A: SiHy CL; Silicone hydrogel (SiHy) CL wear at least 3 days per week and at least 8 hours per day;	Device: 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; Device: Tactile Esthesiometer Prototype; A round plastic nozzle (1.8mm diameter) used as a stimulus for corneal sensation threshold measurement; Device: Cochet Bonnet esthesiometer; A nylon thread (0.12mm diameter) used as a stimulus for corneal sensation threshold measurement
EXPERIMENTAL: Group B: RGP CL; Rigid gas permeable (RGP) CL wear at least 3 days per week and at least 8 hours per day;	Device: 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; Device: Tactile Esthesiometer Prototype; A round plastic nozzle (1.8mm diameter) used as a stimulus for corneal sensation threshold measurement; Device: Cochet Bonnet esthesiometer; A nylon thread (0.12mm diameter) used as a stimulus for corneal sensation threshold measurement
EXPERIMENTAL: Group C: no CL wear; No current CL wear for at least 3 months;	Device: 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; Device: Tactile Esthesiometer Prototype; A round plastic nozzle (1.8mm diameter) used as a stimulus for corneal sensation threshold measurement; Device: Cochet Bonnet esthesiometer; A nylon thread (0.12mm diameter) used as a stimulus for corneal sensation threshold measurement

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Repeatability of mechanical corneal sensation thresholds with the Cochet Bonnet esthesiometer	Evaluation of repeatability of mechanical corneal sensation thresholds for the measurement with the Cochet Bonnet instrument (in mN): the corneal sensation thresholds will be obtained with the double staircase method (with forced choice) and the stimulus represents a nylon thread, whereby its force is proportional to the length of the nylon thread applied to the corneal surface.	two weeks
Repeatability of mechanical corneal sensation thresholds with the liquid jet protoype esthesiometer	Evaluation of repeatability of mechanical corneal sensation thresholds for the measurement with the liquid jet esthesiometer prototype instrument (in mbar): the corneal sensation thresholds will be obtained with the double staircase method (with forced choice) and the stimulus represents a liquid jet (consisting of isotonic saline solution).	two weeks
Repeatability of mechanical corneal sensation thresholds with the tactile prototype esthesiometer	Evaluation of variability / repeatability of mechanical corneal sensation thresholds for the measurement with the tactile esthesiometer prototype instrument (in mN): the corneal sensation thresholds will be obtained with the double staircase method (with forced choice) and the stimulus represents a small, round plastic ball.	two weeks

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Correlation between corneal sensation thresholds with the Cochet Bonnet esthesiometer	Correlation between corneal sensitivity thresholds (in mN) obtained with the Cochet Bonnet esthesiometer	one day
Correlation between corneal sensation thresholds with the liquid jet prototype esthesiometer	Correlation between corneal sensitivity thresholds (in mbar) obtained with the liquid jet prototype esthesiometer	one day
Correlation between corneal sensation thresholds with the tactile prototype esthesiometer	Correlation between corneal sensitivity thresholds (in mN) obtained with the tactile prototype esthesiometer	one day
Comparison of corneal sensation thresholds, obtained with the Cochet Bonnet esthesiometer, between the three groups in the study population	Comparison of corneal sensation thresholds obtained with the Cochet Bonnet esthesiometer between the three groups in the study population	two weeks
Comparison of corneal sensation thresholds, obtained with the liquid jet prototype esthesiometer, between the three groups in the study population	Comparison of corneal sensation thresholds, obtained with the liquid jet prototype esthesiometer, between the three groups in the study population	two weeks
Comparison of corneal sensation thresholds, obtained with the tactile prototype esthesiometer, between the three groups in the study population	Comparison of corneal sensation thresholds, obtained with the tactile prototype esthesiometer, between the three groups in the study population	two weeks

Collaborators and Investigators

• Sponsor: Daniela Nosch
• Investigators: Principal Investigator: Daniela S Nosch, PhD, University of Applied Sciences and Arts Northwestern Switzerland FHNW

Publications and helpful links

General Publications

• 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.
• Bergenske PD, Polse KA. The effect of rigid gas permeable lenses on corneal sensitivity. J Am Optom Assoc. 1987 Mar;58(3):212-5.
• 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.
• 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.
• 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. Erratum In: Exp Eye Res. 2003 Aug;77(2):253.
• 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.
• 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.
• 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.
• 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.
• 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.

Study record dates

Study Major Dates

• Study Start (ACTUAL): May 1, 2021
• Primary Completion (ACTUAL): December 20, 2021
• Study Completion (ACTUAL): December 20, 2021

Study Registration Dates

• First Submitted: March 11, 2021
• First Submitted That Met QC Criteria: March 15, 2021
• First Posted (ACTUAL): March 18, 2021

Study Record Updates

• Last Update Posted (ACTUAL): March 17, 2022
• Last Update Submitted That Met QC Criteria: March 16, 2022
• Last Verified: March 1, 2022

More Information

Terms related to this study

• Keywords: cornea; corneal sensitivity; contact lens wear; ocular surface sensation
• Additional Relevant MeSH Terms: Eye Diseases; Corneal Diseases
• Other Study ID Numbers: 2021-00438

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No