Photorefractive Intrastromal Crosslinking (PiXL) for the Treatment of Progressive Keratoconus

NCT ID: NCT03990506

Last Updated: 2023-09-01

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

COMPLETED

Clinical Phase

NA

Total Enrollment

32 participants

Study Classification

INTERVENTIONAL

Study Start Date

2019-04-02

Study Completion Date

2023-01-24

Brief Summary

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The purpose of this study is to evaluate the efficacy, safety and postoperative ocular discomfort by comparing individually customized Photorefractive intrastromal crosslinking (PiXL) for progressive Keratoconus. The study compares two different protocols, PiXL with corneal epithelium debridement (Epi-off) and PiXL without epithelium debridement in high oxygen environment (Epi-on), with the hypothesis that Epi-on gives less postoperative ocular discomfort.

Detailed Description

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The study is designed as a prospective, single-masked intraindividually comparing randomized clinical trial involving participants of both genders aged 18-35 years with Keratoconus planned for routine corneal crosslinking at the Department of Ophthalmology, Umeå University Hospital, Umeå, Sweden. The study includes 32 participants with bilateral Keratoconus, receiving Epi-off PiXL (n=32) in one eye and Epi-on PiXL in high oxygen environment (n=32) in the fellow eye. The participants are randomized to epi-on PiXL utilizing block randomization with a sample size of 16 in each block; 16 right eyes and 16 left eyes. All participants are informed about the procedures before consenting to participate in the study.

At baseline, before treatment, each eye is examined with slit-lamp microscopy, subjective refraction, determination of uncorrected (UCVA), low contrast visual acuity at 2.5 percentage contrast and 10 percentage contrast and best corrected (BSCVA) visual acuities using the LogMAR fast protocol and intraocular pressure (IOP) using Goldmann applanation tonometry. Under standardized, mesopic light conditions each eye is evaluated by keratometry readings and central corneal thickness using Schemipflug camera measurements, Pentacam HR® (Oculus, Inc. Lynnwood, WA).

Endothelial cellcount is assessed (SP-2000P, Topcon, Inc) and total ocular wavefront is measured with iTrace (Tracey Technologies, Inc.).

Ocular discomfort is subjectively evaluated in each eye by a specific visual analogous rating scale at 4h, 8h 24h and thereafter daily up to 1 week postoperatively.

All the above mentioned examinations are repeated at 1, 3, 6, 12 and 24 months after treatment. At 1 day and 1 week after treatment, solely UCVA, Auto-refractor measurements and slit-lamp examination are evaluated.

Conditions

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Keratoconus Corneal Crosslinking Corneal Biomechanics Corneal Densitometry Scheimpflug Photography Corneal Disease Eye Diseases

Study Design

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Allocation Method

RANDOMIZED

Intervention Model

PARALLEL

Prospective, single-masked intraindividually comparing randomized controlled trial. Participants will be randomized to receive Epi-off PiXL in one eye and Epi-on PiXL in the other, which is masked to the participant. The participant can choose to treat in eye at a time or both eyes during the same visit.
Primary Study Purpose

TREATMENT

Blinding Strategy

SINGLE

Participants
The participants are not aware which eye will receive the Epi-off PiXL treatment and which eye will receive the Epi-on PiXL treatment.

Study Groups

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Epi-on PiXL

Photorefractive intrastromal corneal crosslinking without epithelium debridement during humidified high oxygen flow.

Group Type EXPERIMENTAL

Epi-on PiXL

Intervention Type PROCEDURE

Photorefractive intrastromal crosslinking (PiXL) After local anaesthetics, the cornea is soaked in Riboflavin by repeated topical application during 10 minutes. For masking purposes, epithelial debridement is simulated by moving a scraping instrument in front of the cornea. A Riboflavin soaked sponge is used to lightly disrupt the epithelium tight junctions, without epithelium debridement. The cornea is illuminated with PiXL under 16:40 minutes during continuously delivery of humidified high oxygen via specific oxygen goggles. The UV-dosage is individually customized based upon Kmax; \< 45D, 7.2J/cm2; 45-50D, 10J/cm2; \> 50D, 15 J/cm2.

Epi-off PiXL

Photorefractive intrastromal corneal crosslinking with epithelium debridement.

Group Type ACTIVE_COMPARATOR

Epi-Off PiXL

Intervention Type PROCEDURE

Photorefractive intrastromal crosslinking (PiXL) After local anaesthetics, the corneal epithelium is debrided and the cornea is soaked in Riboflavin by repeated topical application during 10 minutes. The cornea is then illuminated with individually customized topography-guided PiXL under 16:40 minutes. The UV-dosage is individually customized based upon Kmax; \< 45D, 7.2J/cm2; 45-50D, 10J/cm2; \> 50D, 15 J/cm2.

Interventions

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Epi-on PiXL

Photorefractive intrastromal crosslinking (PiXL) After local anaesthetics, the cornea is soaked in Riboflavin by repeated topical application during 10 minutes. For masking purposes, epithelial debridement is simulated by moving a scraping instrument in front of the cornea. A Riboflavin soaked sponge is used to lightly disrupt the epithelium tight junctions, without epithelium debridement. The cornea is illuminated with PiXL under 16:40 minutes during continuously delivery of humidified high oxygen via specific oxygen goggles. The UV-dosage is individually customized based upon Kmax; \< 45D, 7.2J/cm2; 45-50D, 10J/cm2; \> 50D, 15 J/cm2.

Intervention Type PROCEDURE

Epi-Off PiXL

Photorefractive intrastromal crosslinking (PiXL) After local anaesthetics, the corneal epithelium is debrided and the cornea is soaked in Riboflavin by repeated topical application during 10 minutes. The cornea is then illuminated with individually customized topography-guided PiXL under 16:40 minutes. The UV-dosage is individually customized based upon Kmax; \< 45D, 7.2J/cm2; 45-50D, 10J/cm2; \> 50D, 15 J/cm2.

Intervention Type PROCEDURE

Eligibility Criteria

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Inclusion Criteria

* Patients planned for corneal crosslinking.
* Progressive keratoconus documented with a consistent decrease of best corrected visual acuity with no other explanation, an unquestionable historical progression, or a progression documented with the Pentacam Scheimpflug camera with at least 2 of the following: progressive anterior and/or posterior corneal steepening and/or progressive corneal thinning and/or increased rate of corneal thickness change from the periphery to the center.
* A keratoconus diagnosis based on abnormal posterior elevation, abnormal corneal thickness distribution and clinical noninflammatory corneal thinning using the "Belin/Ambrósio enhanced ectasia" measurements of the Pentacam Scheimpflug camera.
* Minimum corneal thickness of 400 µm at the thinnest point before epithelial removal.
* 18-35 years of age
* No ocular abnormalities except keratoconus
* No previous ocular surgery
* No cognitive insufficiency interfering with the informed consent.

Exclusion Criteria

* Age under 18 or over 35
* Any corneal abnormalities except keratoconus
* Pregnancy or lactation
* Previous ocular surgery
* Cognitive insufficiency
Minimum Eligible Age

18 Years

Maximum Eligible Age

35 Years

Eligible Sex

ALL

Accepts Healthy Volunteers

No

Sponsors

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Glaukos Corporation

INDUSTRY

Sponsor Role collaborator

Umeå University

OTHER

Sponsor Role lead

Responsible Party

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Anders Behndig

Principal Investigator

Responsibility Role PRINCIPAL_INVESTIGATOR

Principal Investigators

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Anders Behndig, MD, PhD

Role: PRINCIPAL_INVESTIGATOR

Department of Clinical Sciences/Ophthalmology, Umeå University

Locations

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Department of Clinical Sciences/Ophthalmology, Umeå University

Umeå, , Sweden

Site Status

Countries

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Sweden

Other Identifiers

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PiXLKC-I

Identifier Type: -

Identifier Source: org_study_id

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