NCT03249233

Brief Summary

The purpose of this study is to investigate changes in the corneal thickness of scleral contact lens wearers in a keratoconic (KC) population and compare to age-matched controls. The hypothesis is that scleral contact lens wear is associated with low levels of corneal hypoxia including measurable changes in corneal thickness. Corneal thickness will be altered post scleral lens wear compared to pre-lens wear and the amount of alteration will correlate to the fitting characteristics in the central zone of the scleral lenses. We propose to take a sample of keratoconic and control participants, fit them in scleral lenses, and to measure topographic corneal thickness after 8-10 hours of scleral lens wear after three weeks of wear, to compare two instruments in the measurement of corneal thickness, and to compare the effects of varying central corneal clearance of the scleral lens on corneal thickness.

Trial Health

43
At Risk

Trial Health Score

Automated assessment based on enrollment pace, timeline, and geographic reach

Trial has exceeded expected completion date
Enrollment
40

participants targeted

Target at P25-P50 for not_applicable

Timeline
Completed

Started Jun 2017

Longer than P75 for not_applicable

Geographic Reach
1 country

1 active site

Status
unknown

Health score is calculated from publicly available data and should be used for screening purposes only.

Trial Relationships

Click on a node to explore related trials.

Study Timeline

Key milestones and dates

First Submitted

Initial submission to the registry

June 15, 2017

Completed
7 days until next milestone

Study Start

First participant enrolled

June 22, 2017

Completed
2 months until next milestone

First Posted

Study publicly available on registry

August 15, 2017

Completed
3.3 years until next milestone

Primary Completion

Last participant's last visit for primary outcome

December 1, 2020

Completed
Same day until next milestone

Study Completion

Last participant's last visit for all outcomes

December 1, 2020

Completed
Last Updated

April 10, 2020

Status Verified

April 1, 2020

Enrollment Period

3.4 years

First QC Date

June 15, 2017

Last Update Submit

April 8, 2020

Conditions

KeratoconusHealthy Controls

Outcome Measures

Primary Outcomes (1)

  • Corneal Thickness

    Corneal thickness after 8-10 hours of scleral contact lens wear will be measured with the Spectralis OCT and Oculus Pentacam

    6 weeks

Secondary Outcomes (5)

  • Visual acuity

    6 weeks

  • Conjunctival redness

    6 weeks

  • Corneal and conjunctival staining

    6 weeks

  • Tear biochemistry: proteases and cytokines

    6 weeks

  • Tear biochemistry: cell count

    6 weeks

Study Arms (4)

Keratoconics wearing ZenLens with high central clearance

EXPERIMENTAL

Scleral contact lenses designed to provide approximately 450 microns of central clearance.

Device: ZenLens™

Keratoconics wearing ZenLens with low central clearance

EXPERIMENTAL

Scleral contact lenses designed to provide approximately 350 microns of central clearance.

Device: ZenLens™

Healthy controls wearing ZenLens with high central clearance

ACTIVE COMPARATOR

Scleral contact lenses designed to provide approximately 450 microns of central clearance.

Device: Zen™ RC

Healthy controls wearing ZenLens with low central clearance

ACTIVE COMPARATOR

Scleral contact lenses designed to provide approximately 350 microns of central clearance.

Device: Zen™ RC

Interventions

ZenLens™DEVICE

The ZenLens™ semi-scleral lenses are manufactured by Alden Optic Laboratories Inc., Lancaster, NY. They will be made in Boston XO material.

Keratoconics wearing ZenLens with high central clearanceKeratoconics wearing ZenLens with low central clearance
Zen™ RCDEVICE

The Zen™ RC semi-scleral lenses are manufactured by Alden Optic Laboratories Inc., Lancaster, NY. They will be made in Boston XO material.

Healthy controls wearing ZenLens with high central clearanceHealthy controls wearing ZenLens with low central clearance

Eligibility Criteria

Age18 Years+
Sexall
Healthy VolunteersYes
Age GroupsAdult (18-64), Older Adult (65+)

You may qualify if:

  • 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.
  • Had been NOT 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.

You may not qualify if:

  • Is using any topical medications that will affect ocular health.
  • Has any ocular pathology or severe insufficiency of lacrimal secretion (severe dry eyes) that 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 penetrating keratoplasty.
  • 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, used in this study.
  • Is using any topical medications that will affect ocular health.
  • Has any ocular pathology or severe insufficiency of lacrimal secretion (severe dry eyes) that 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.
  • +1 more criteria

Contact the study team to confirm eligibility.

Sponsors & Collaborators

Study Sites (1)

University of Waterloo School of Optometry and Vision Science

Waterloo, Ontario, N2L3G1, Canada

RECRUITING

Related Publications (5)

  • van der Worp E, Bornman D, Ferreira DL, Faria-Ribeiro M, Garcia-Porta N, Gonzalez-Meijome JM. Modern scleral contact lenses: A review. Cont Lens Anterior Eye. 2014 Aug;37(4):240-50. doi: 10.1016/j.clae.2014.02.002. Epub 2014 Mar 12.

    PMID: 24631015BACKGROUND

  • Romero-Rangel T, Stavrou P, Cotter J, Rosenthal P, Baltatzis S, Foster CS. Gas-permeable scleral contact lens therapy in ocular surface disease. Am J Ophthalmol. 2000 Jul;130(1):25-32. doi: 10.1016/s0002-9394(00)00378-0.

    PMID: 11004256BACKGROUND

  • Walker MK, Bergmanson JP, Miller WL, Marsack JD, Johnson LA. Complications and fitting challenges associated with scleral contact lenses: A review. Cont Lens Anterior Eye. 2016 Apr;39(2):88-96. doi: 10.1016/j.clae.2015.08.003. Epub 2015 Sep 2.

    PMID: 26341076BACKGROUND

  • Ucakhan OO, Ozkan M, Kanpolat A. Corneal thickness measurements in normal and keratoconic eyes: Pentacam comprehensive eye scanner versus noncontact specular microscopy and ultrasound pachymetry. J Cataract Refract Surg. 2006 Jun;32(6):970-7. doi: 10.1016/j.jcrs.2006.02.037.

    PMID: 16814055BACKGROUND

  • Liesegang TJ. Contact lens-related microbial keratitis: Part I: Epidemiology. Cornea. 1997 Mar;16(2):125-31.

    PMID: 9071523BACKGROUND

MeSH Terms

Conditions

Keratoconus

Condition Hierarchy (Ancestors)

Corneal DiseasesEye Diseases

Study Officials

  • Luigina Sorbara, OD MSc

    University of Waterloo

    PRINCIPAL INVESTIGATOR

Central Study Contacts

Kirsten S Carter, BSc OD

CONTACT

5193018487kirsten.carter@uwaterloo.ca

Study Design

Study Type
interventional
Phase
not applicable
Allocation
RANDOMIZED
Masking
DOUBLE
Who Masked
PARTICIPANT, INVESTIGATOR
Purpose
TREATMENT
Intervention Model
PARALLEL
Sponsor Type
OTHER
Responsible Party
PRINCIPAL INVESTIGATOR
PI Title
Associate Professor

Study Record Dates

First Submitted

June 15, 2017

First Posted

August 15, 2017

Study Start

June 22, 2017

Primary Completion

December 1, 2020

Study Completion

December 1, 2020

Last Updated

April 10, 2020

Record last verified: 2020-04

Data Sharing

IPD Sharing
Will not share

Locations

CA(1)