Corneal Thickness Changes With Scleral Contact Lenses

NCT ID: NCT03249233

Last Updated: 2020-04-10

Study Results

Results pending

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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Recruitment Status

UNKNOWN

Clinical Phase

NA

Total Enrollment

40 participants

Study Classification

INTERVENTIONAL

Study Start Date

2017-06-22

Study Completion Date

2020-12-31

Brief Summary

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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.

Detailed Description

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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.

This will be a prospective, dispensing study design. The study will involve up to 20 keratoconic participants and up to 20 age matched controls. Participants will attend 1 screening/fitting visit wearing their habitual contact lenses where the two test lens designs (350 and 450microns) will be fitted. There will then be a delivery visit for each design (randomly selected) and a single follow up visit after 8-10 hours of scleral lens wear, three weeks later. A washout period of a minimum of 48 hours will be applied between the cross-over of each lens design. Lenses to be worn in this study will be made of Boston XO material and are approved by Health Canada. The lenses will have a diameter of 14.8-17.0mm with a high and low sagittal depth in the corneal zone. As to which of the two lenses is being assessed, both the investigator and the participant will be masked as the assistant will provide the lenses in an unlabeled case. Masking the investigator will prevent bias when measuring corneal thickness and analyzing the data. The objectives of this study are 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. Secondary objectives include comparing ocular physiological outcomes between the two test lens designs. 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.

Conditions

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Keratoconus Healthy Controls

Study Design

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Allocation Method

RANDOMIZED

Intervention Model

PARALLEL

Primary Study Purpose

TREATMENT

Blinding Strategy

DOUBLE

Participants Investigators

Study Groups

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Keratoconics wearing ZenLens with high central clearance

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

Group Type EXPERIMENTAL

ZenLens™

Intervention Type 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 low central clearance

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

Group Type EXPERIMENTAL

ZenLens™

Intervention Type DEVICE

The ZenLens™ 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 clearance

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

Group Type ACTIVE_COMPARATOR

Zen™ RC

Intervention Type DEVICE

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 low central clearance

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

Group Type ACTIVE_COMPARATOR

Zen™ RC

Intervention Type DEVICE

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

Interventions

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ZenLens™

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

Intervention Type DEVICE

Zen™ RC

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

Intervention Type DEVICE

Eligibility Criteria

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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.


* 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.

Exclusion Criteria

* 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.
* Has any known allergies or sensitivity to the diagnostic pharmaceuticals or products, such as fluorescein, used in this study.
Minimum Eligible Age

18 Years

Eligible Sex

ALL

Accepts Healthy Volunteers

Yes

Sponsors

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Bausch & Lomb Incorporated

INDUSTRY

Sponsor Role collaborator

University of Waterloo

OTHER

Sponsor Role lead

Responsible Party

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Luigina Sorbara

Associate Professor

Responsibility Role PRINCIPAL_INVESTIGATOR

Principal Investigators

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Luigina Sorbara, OD MSc

Role: PRINCIPAL_INVESTIGATOR

University of Waterloo

Locations

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University of Waterloo School of Optometry and Vision Science

Waterloo, Ontario, Canada

Site Status RECRUITING

Countries

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Canada

Central Contacts

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Kirsten S Carter, BSc OD

Role: CONTACT

5193018487

Facility Contacts

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Kirsten S Carter, BSc OD

Role: primary

5193018487

Luigina Sorbara, OD MSc

Role: backup

519-888-4567 ext. 33085

References

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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.

Reference Type BACKGROUND
PMID: 24631015 (View on PubMed)

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.

Reference Type BACKGROUND
PMID: 11004256 (View on PubMed)

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.

Reference Type BACKGROUND
PMID: 26341076 (View on PubMed)

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.

Reference Type BACKGROUND
PMID: 16814055 (View on PubMed)

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

Reference Type BACKGROUND
PMID: 9071523 (View on PubMed)

Other Identifiers

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22186

Identifier Type: -

Identifier Source: org_study_id

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