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Impact of Scleral Contact Lens Wear on Corneal Nerves in Keratoconus

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ClinicalTrials.gov Identifier: NCT03091101
Recruitment Status : Completed
First Posted : March 27, 2017
Last Update Posted : June 11, 2018
Sponsor:
Collaborator:
Precision Technology Services Ltd
Information provided by (Responsible Party):
Edward Lum, University of Waterloo

Brief Summary:
The purpose of this study is to investigate changes in corneal innervation during scleral contact lens wear in a keratoconic population. Specifically, changes in corneal sensitivity and nerve fiber density from baseline in the central and mid-peripheral corneal locations will be measured over a 6-month lens wear period. An additional aim of the study is to investigate the impact of scleral lens wear on corneal inflammation within the same study group. This will be achieved by comparing dendritic cell density change from baseline over the study period.

Condition or disease Intervention/treatment Phase
Keratoconus Device: Scleral lens wearing keratoconics Not Applicable

Detailed Description:

The human cornea is a densely innervated tissue that provides a high level of sensitivity to foreign objects or noxious substances. The innervation of the cornea also plays an important role in the tropic maintenance and repair of the corneal surface. Any alterations to the normal innervation of the cornea not only lessen the ability to detect foreign objects that could damage the ocular surface, but also reduce its wound healing ability. Previous studies have shown rigid contact lens wear reduces corneal sensitivity and nerve fiber density in keratoconic subjects. Scleral contact lenses are large diameter rigid gas permeable lenses that rests on the sclera while vaulting over the cornea with a fluid reservoir. The use of scleral contact lenses is becoming one of the current standard nonsurgical management of corneal dystrophies such as keratoconus, mainly due to the improved comfort and vision quality compared to conventional rigid lenses. Despite these patient benefits, little is known about the impact of scleral contact lens wear on corneal sensitivity and nerve morphology in keratoconus.

The purpose of this study is to investigate changes in corneal innervation during scleral contact lens wear in a keratoconic population. Specifically, changes in corneal sensitivity and nerve fiber density from baseline in the central and mid-peripheral corneal locations will be measured over a 6-month lens wear period. An additional aim of the study is to investigate the impact of scleral lens wear on corneal inflammation within the same study group. This will be achieved by comparing dendritic cell density change from baseline over the study period.

The investigators propose to take a sample of keratoconic participants and fit them in scleral lenses and:

  1. Measure corneal sensitivity at two corneal locations before and after 1-month, 3-months and 6-months of scleral lens wear.
  2. Capture images of the sub-basal nerve plexus in vivo using laser-scanning confocal microscopy at similar corneal locations and study visits.
  3. Calculate nerve morphology parameters and dendritic cell density from these captured images.

Up to 15 participants will be enrolled.


Study Type : Interventional  (Clinical Trial)
Actual Enrollment : 8 participants
Intervention Model: Single Group Assignment
Masking: None (Open Label)
Primary Purpose: Other
Official Title: Impact of Scleral Contact Lens Wear on Corneal Sensitivity, Nerve Morphology and Inflammation in Keratoconic Eyes
Actual Study Start Date : March 15, 2017
Actual Primary Completion Date : March 21, 2018
Actual Study Completion Date : March 21, 2018

Resource links provided by the National Library of Medicine

MedlinePlus related topics: Eye Wear

Arm Intervention/treatment
Experimental: Scleral lens wearing keratoconics
Newly diagnosed keratoconics with no previous rigid lens wear fitted with Sceral contact lenses
Device: Scleral lens wearing keratoconics
Cohort of keratoconics fitted with scleral lenses and monitored over 6 months




Primary Outcome Measures :
  1. Corneal sensitivity [ Time Frame: 6-month lens wear period ]
    Indication of functional change in corneal innervation from scleral lens wear by measuring change in sensitivity threshold (grams/sq.mm) over time

  2. Subbasal nerve fiber density [ Time Frame: 6-month lens wear period ]
    Indication of morphological change in corneal innervation from scleral lens wear by measuring nerve fiber density changes (mm/sq.mm) in the central subbasal nerve fiber layer location over time.


Secondary Outcome Measures :
  1. Corneal inflammation [ Time Frame: 6-month lens wear period ]
    Changes in dendritic cell density (number/sq.mm) as a marker of corneal inflammation



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Ages Eligible for Study:   18 Years and older   (Adult, Older Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   Yes
Criteria

Inclusion Criteria:

  • Had been diagnosed with keratoconus in at least one eye.
  • Is at least 18 years of age and has full legal capacity to volunteer.
  • Has read and understood the information consent letter.
  • Is willing and able to follow instructions and maintain the appointment schedule.

Exclusion Criteria:

  • Have worn rigid corneal lenses for more than several days over the past year
  • Is using any topical medications that will affect ocular health.
  • Has any ocular pathology or systemic disease that may lead to severe insufficiency of lacrimal secretion (severe dry eyes) or corneal hypoesthesia which would affect the wearing of contact lenses.
  • Has persistent, clinically significant corneal or conjunctival staining using sodium fluorescein dye.
  • Has any clinically significant lid or conjunctival abnormalities and active neovascularization.
  • Is aphakic.
  • Has undergone any corneal surgery.
  • Is participating in any other type of eye related clinical or research study.
  • Has any known allergies or sensitivity to the diagnostic pharmaceuticals or products, such as fluorescein and topical anesthetics, used in this study.

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT03091101


Locations
Canada, Ontario
School of Optometry and Vision Science
Waterloo, Ontario, Canada, N2T2T3
Sponsors and Collaborators
University of Waterloo
Precision Technology Services Ltd
Investigators
Principal Investigator: Edward Lum, PhD Univerity of Waterloo

Responsible Party: Edward Lum, Post-Doctorial Fellow, University of Waterloo
ClinicalTrials.gov Identifier: NCT03091101     History of Changes
Other Study ID Numbers: ORE#21910
First Posted: March 27, 2017    Key Record Dates
Last Update Posted: June 11, 2018
Last Verified: June 2018
Individual Participant Data (IPD) Sharing Statement:
Plan to Share IPD: Undecided

Studies a U.S. FDA-regulated Drug Product: No
Studies a U.S. FDA-regulated Device Product: No
Product Manufactured in and Exported from the U.S.: No

Keywords provided by Edward Lum, University of Waterloo:
keratoconus
corneal innervation
scleral contact lenses

Additional relevant MeSH terms:
Keratoconus
Corneal Diseases
Eye Diseases