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

University of Waterloo

Status: Completed

Conditions: Keratoconus

Treatments: Device: ZenLens

Study type: Interventional

Funder types: Other; Industry

Identifiers

NCT02806921

14620

Details and patient eligibility

About

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.

Full description

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.

Enrollment: 13 patients

Sex: All

Ages: 18+ years old

Volunteers: Accepts Healthy Volunteers

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.

Trial design

Primary purpose: Treatment

Allocation: Randomized

Interventional model: Crossover Assignment

Masking: Double Blind

---

13 participants in 2 patient groups

ZenLens with Low limbal clearance

Active Comparator group

Description:

Scleral contact lens designed to provide approximately 25 microns of limbal clearance.

Treatment:

Device: ZenLens

ZenLens with High limbal clearance

Active Comparator group

Description:

Scleral contact lens designed to provide approximately 80 microns of limbal clearance.

Treatment:

Device: ZenLens