Changes in the Tear Film With Scleral Contact Lens Wear for Keratoconic Eyes

Study Overview
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Brief Summary
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The purpose of this study is to investigate changes in the level of inflammatory mediators in the tear film of scleral contact lens wearers in a keratoconic population.

Detailed Description
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Scleral contact lenses are rigid gas permeable lenses designed to rest on the sclera while vaulting over the cornea with a fluid reservoir. The use of scleral contact lenses has become the current standard of practice as a nonsurgical management of corneal ectasia and ocular surface diseases. Cases have been recently presented of scleral lens wearers exhibiting adverse corneal findings and conjunctival injection from lens wear. These findings are likely associated with the mechanical and hypoxic effects due to poor fitting characteristics at the limbal area. Tear film analysis detecting changes in the levels of proteinases and cytokines have helped researchers gain a better understanding of the pathophysiology of complications in soft contact lenses wearers, dry eye, and keratoconus. Ultimately, this study will provide insights in relating scleral lens fitting characteristics and corneal and limbal physiological responses.

Official Title
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Protease and Cytokine Composition in Post Lens Tear Reservoir of Scleral Lenses for Keratoconic Eyes

Conditions
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Keratoconus

Intervention / Treatment
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* Device: ZenLens


Participation Criteria
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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. 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 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.

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: ZenLens with Low limbal clearance<br>Scleral contact lens designed to provide approximately 25 microns of limbal clearance. | Device: ZenLens<br>* The ZenLens™ semi-scleral lenses are manufactured by Alden Optic Laboratories Inc., Lancaster, NY. They will be made in Boston XO material.<br>|
| Active Comparator: ZenLens with High limbal clearance<br>Scleral contact lens designed to provide approximately 80 microns of limbal clearance. | Device: ZenLens<br>* The ZenLens™ semi-scleral lenses are manufactured by Alden Optic Laboratories Inc., Lancaster, NY. They will be made in Boston XO material.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Tear Protein | To measure the level proteases and cytokines in each of the samples using Meso Scale Discovery system (MSD-ECL). | 2 weeks of lens wear with daily schedule of 6-8 hours. | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Comfort | Participants will be asked to rate their ocular comfort, dryness, burning and vision with the contact lenses. | 2 weeks of lens wear with daily schedule of 6-8 hours. | 
| Bulbar and limbal hyperemia | The eyes of the participants will be imaged using the Keratograph® 5. | 2 weeks of lens wear with daily schedule of 6-8 hours. | 
| Corneal thickness | Their corneal thickness will be measured with the Visante OCT. | 2 weeks of lens wear with daily schedule of 6-8 hours. | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Scleral Contact Lens, Tear Proteases, Tear Cytokines