MyopiaNCT03987880
Photorefractive Intrastromal Corneal Crosslinking as a Treatment for Low Grade Myopia
A study testing 4.0 mm treatment and 3.5 mm treatment in people with Myopia and Corneal Crosslinking, run by Umeå University at 1 site in Sweden.
Trial summary
To assess the improvement in refractive error and the corneal endothelial safety with a customized corneal crosslinking treatment regimen for low grade myopia. The study compares two treatment protocols, a 4.0-mm central ring-shaped zone with a 3.5-mm central ring-shaped zone in high oxygen environment without corneal… Read more about this study
- Who is it for?
- Ages 18 to 35 yearsHealthy volunteers can take part
- Conditions the study is for
- Myopia, Corneal Crosslinking, Refractive Errors
- What is being tested?
- 4.0 mm treatment and 3.5 mm treatment
- Type of treatment
- Surgery or procedure
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 27 participants
- Where
- 1 siteSweden
- Study dates
- 22 Jan 2018to 15 Oct 2020
- Phase
- Interventional
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 35 years
- All sexes
- Healthy volunteers accepted
- Adult
Who may be able to join
- Spherical equivalent on distance subjective refraction between -0.50D and -2.50D.
- Astigmatism ≤ 0.75D
- Stable myopia. Maximum change in refraction of 0.50D in the last 2 years.
- Best corrected visual acuity of at least 0.00 logMAR (ETDRS chart).
- Thinnest pachymetry reading ≥ 440 μm.
- No previous ocular surgery.
- No cognitive insufficiency interfering with the informed consent.
Who cannot join
- History of or current condition, disease, surgery or medication with ocular effects that could affect the outcomes of the treatment.
- Allergy to any substance or device used in the study.
- Cognitive insufficiency interfering with the informed consent.
Trial locations and contacts
1 site in 1 country.
Sweden1 site
Department of Clinical Sciences/Ophthalmology, Umeå University
Umeå, 901 85
About this study
Official title: Comparison of a 4-mm Ring Shaped and 3.5-mm Ring Shaped PiXL Protocol for Low Grade Myopia
To assess the improvement in refractive error and the corneal endothelial safety with a customized corneal crosslinking treatment regimen for low grade myopia. The study compares two treatment protocols, a 4.0-mm central ring-shaped zone with a 3.5-mm central ring-shaped zone in high oxygen environment without corneal epithelial debridement.
Read the detailed description
The study design is a prospective, single-masked intraindividually comparing randomized controlled trial, conducted at the Department of Clinical Sciences / Ophthalmology, Umeå University Hospital, Umeå, Sweden. The study includes healthy men and women with low grade myopia, aged between 18-35 years and involves 27 participants with a myopia of -0.5 to -2.5 diopters (D) and astigmatism of ≤0.75D. All participants are treated with phototherapeutic intrastromal corneal collagen cross-linking (PiXL) without epithelial debridement (epi-on), after topical riboflavin. Both eyes are treated and randomized to receive ultraviolet (UV) light according to PiXL 4.0 mm treatment zone in one eye and PiXL 3.5 mm treatment zone in the other, which is masked to the participant. For myopia <0.75D, 10 J/cm^2 is used and for higher levels of myopia 15J/cm^2 is used. Throughout the treatment, humidified oxygen is continuously delivered around the eye using an oxygen mask to achieve an oxygen concentration of ≥95 percentage. All participants are informed about the procedures and provide oral and written consent before inclusion in the study.
At baseline, each eye is examined with slit-lamp microscopy, subjective refraction, determination of uncorrected (UCVA), low contrast visual acuity at 2.5 percentage 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, central corneal thickness and after treatment also the depth of demarcation lines, extracted from Schemipflug camera measurements, Pentacam HR® (Oculus, Inc. Lynnwood, WA). Central corneal endothelial photographs are taken with the Topcon SP-2000P specular microscope (Topcon Europe B.V., Capelle a/d Ijssel, the Netherlands), from which the corneal endothelial cell count is manually calculated from a cluster of 25 cells from each photograph. Total ocular wavefront is measured with iTrace (Tracey Technologies, Inc.).
All the above mentioned examinations are reassessed at 1, 3 and 6 and 12 months after treatment. At 1 day and 1 week after treatment, solely UCVA, Auto refractor measurements, slit-lamp examination and a subjective comparison of discomfort and visual performance in each eye are evaluated.
- Conditions
- Myopia, Corneal Crosslinking, Refractive Errors, Eye Diseases
- Being tested
- 4.0 mm treatment, 3.5 mm treatment
- Medical subject headings
- Myopia, Refractive Errors, Eye Diseases
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
4.0 mm treatmentProcedure or surgery
PiXL treatment with UV irradiation in a central 4.0-mm ring-shaped zone of the cornea.
3.5 mm treatmentProcedure or surgery
PiXL treatment with UV irradiation in a central 3.5-mm ring-shaped zone of the cornea.
| Study group | Role | What they receive |
|---|---|---|
| 4.0 mm zone | Active comparator | PiXL treatment with UV irradiation in a central 4.0-mm ring-shaped zone of the cornea. The area consist of three rings with a central 2-mm zone that is left untreated. The energy is higher towards the periphery of the ring-shaped area, reaching its maximum at 2-mm from the corneal centre. Pulsed UV-light, 1s on / 1s off; 30mW. For myopia of less than 0.75D, 10 J/cm2 is used, for higher levels of myopia 15J/cm2 is used. Receives: Procedure: 4.0 mm treatment |
| 3.5 mm zone | Experimental | PiXL treatment with UV irradiation in a central ring-shaped 3.5-mm zone of the cornea, with a central 1.5 mm zone that is left untreated. The illumination area consists of three rings, where the outer and inner ring are thinner than the middle ring. The maximum energy is distributed in the middle ring. Pulsed UV-light, 0.5s on / 1s off; 45mW. For myopia of less than 0.75D, a maximum of 10 J/cm2 is used, for higher levels of myopia a maximum of 15J/cm2 is used. Receives: Procedure: 3.5 mm treatment |
What is being measured
The primary outcome is the main question the study is designed to answer.
Change from baseline in uncorrected visual acuity
Change from baseline in distance uncorrected visual acuity
Measured: 1, 3, 6, 12 and 24 months after treatment
Change from baseline in spherical equivalent
Change from baseline in spherical equivalent on subjective distance refraction
Measured: 1, 3, 6, 12 and 24 months after treatment
Secondary outcomes (2)
Change from baseline in corneal endothelial cell density
Change from baseline in central corneal endothelial cell density
Measured: 12 and 24 months after treatment
Change from baseline in best corrected visual acuity
Change from baseline in best spectacle corrected distance visual acuity
Measured: 1, 3, 6, 12 and 24 months after treatment
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted17 Jun 2019
- Study start22 Jan 2018
- Primary completion15 Oct 2020
- Study completion15 Oct 2020
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for MyopiaStudies of the same condition, open and under way.
- More trials run by Umeå UniversityThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Model description
- Prospective, single-masked intraindividually comparing randomized controlled trial. Participants will be randomized to receive ultraviolet (UV) light according to protocol A in one eye and protocol B in the other, which is masked to the participant. Both eyes will be treated during the same visit. Participants are randomized utilizing a computer list of unique random numbers between 1 and 27; an even number will be treated with the 4.0-mm zone in the right eye; an uneven number with the 4.0-mm zone in the left eye.
- Masking
- Single blind
- Who is masked
- Participant
- Enrolment
- 27 participants (actual)
Sponsor and investigators
- Lead sponsor
- Umeå University
- Sponsor type
- University, hospital or other
- Collaborators
- Glaukos Corporation
- Responsible party
- Principal investigator, Anders Behndig, Umeå University
- Investigators
- Anders Behndig, MD, PhD, Principal investigator, Department of Clinical Sciences/Ophthalmology, Umeå University, Umeå, Sweden
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT03987880
- Sponsor's protocol ID
- PiXLMYOP-II
- Status last verified
- Dec 2020
- First submitted
- 12 Jun 2019
- Last updated
- 10 Dec 2020
- Results posted
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 10 Dec 2020. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Comparison of a 4-mm Ring Shaped and 3.5-mm Ring Shaped PiXL Protocol for Low Grade Myopia
- ClinicalTrials.gov ID
- NCT03987880
- Acronym / sponsor ID
- PiXLMYOP-II
- Conditions
- Myopia, Corneal Crosslinking, Refractive Errors, Eye Diseases
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 27 participants (actual)
- Lead sponsor
- Umeå UniversityUniversity, hospital or other
- Collaborators
- Glaukos Corporation
- Study start
- 22 Jan 2018 (actual)
- Primary completion
- 15 Oct 2020 (actual)
- Study completion
- 15 Oct 2020 (actual)
- First posted
- 17 Jun 2019 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
To assess the improvement in refractive error and the corneal endothelial safety with a customized corneal crosslinking treatment regimen for low grade myopia. The study compares two treatment protocols, a 4.0-mm central ring-shaped zone with a 3.5-mm central ring-shaped zone in high oxygen environment without corneal epithelial debridement.
Detailed description
The study design is a prospective, single-masked intraindividually comparing randomized controlled trial, conducted at the Department of Clinical Sciences / Ophthalmology, Umeå University Hospital, Umeå, Sweden. The study includes healthy men and women with low grade myopia, aged between 18-35 years and involves 27 participants with a myopia of -0.5 to -2.5 diopters (D) and astigmatism of ≤0.75D. All participants are treated with phototherapeutic intrastromal corneal collagen cross-linking (PiXL) without epithelial debridement (epi-on), after topical riboflavin. Both eyes are treated and randomized to receive ultraviolet (UV) light according to PiXL 4.0 mm treatment zone in one eye and PiXL 3.5 mm treatment zone in the other, which is masked to the participant. For myopia <0.75D, 10 J/cm^2 is used and for higher levels of myopia 15J/cm^2 is used. Throughout the treatment, humidified oxygen is continuously delivered around the eye using an oxygen mask to achieve an oxygen concentration of ≥95 percentage. All participants are informed about the procedures and provide oral and written consent before inclusion in the study.
At baseline, each eye is examined with slit-lamp microscopy, subjective refraction, determination of uncorrected (UCVA), low contrast visual acuity at 2.5 percentage 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, central corneal thickness and after treatment also the depth of demarcation lines, extracted from Schemipflug camera measurements, Pentacam HR® (Oculus, Inc. Lynnwood, WA). Central corneal endothelial photographs are taken with the Topcon SP-2000P specular microscope (Topcon Europe B.V., Capelle a/d Ijssel, the Netherlands), from which the corneal endothelial cell count is manually calculated from a cluster of 25 cells from each photograph. Total ocular wavefront is measured with iTrace (Tracey Technologies, Inc.).
All the above mentioned examinations are reassessed at 1, 3 and 6 and 12 months after treatment. At 1 day and 1 week after treatment, solely UCVA, Auto refractor measurements, slit-lamp examination and a subjective comparison of discomfort and visual performance in each eye are evaluated.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Single blind (participant)
- Number of arms
- 2
- Model description
- Prospective, single-masked intraindividually comparing randomized controlled trial. Participants will be randomized to receive ultraviolet (UV) light according to protocol A in one eye and protocol B in the other, which is masked to the participant. Both eyes will be treated during the same visit. Participants are randomized utilizing a computer list of unique random numbers between 1 and 27; an even number will be treated with the 4.0-mm zone in the right eye; an uneven number with the 4.0-mm zone in the left eye.
| Arm | Type | Receives |
|---|---|---|
| 4.0 mm zone | Active comparator | Procedure: 4.0 mm treatmentPiXL treatment with UV irradiation in a central 4.0-mm ring-shaped zone of the cornea. The area consist of three rings with a central 2-mm zone that is left untreated. The energy is higher towards the periphery of the ring-shaped area, reaching its maximum at 2-mm from the corneal centre. Pulsed UV-light, 1s on / 1s off; 30mW. For myopia of less than 0.75D, 10 J/cm2 is used, for higher levels of myopia 15J/cm2 is used. |
| 3.5 mm zone | Experimental | Procedure: 3.5 mm treatmentPiXL treatment with UV irradiation in a central ring-shaped 3.5-mm zone of the cornea, with a central 1.5 mm zone that is left untreated. The illumination area consists of three rings, where the outer and inner ring are thinner than the middle ring. The maximum energy is distributed in the middle ring. Pulsed UV-light, 0.5s on / 1s off; 45mW. For myopia of less than 0.75D, a maximum of 10 J/cm2 is used, for higher levels of myopia a maximum of 15J/cm2 is used. |
Who may qualify
- Ages
- 18 to 35 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult
Key inclusion criteria (7 listed)
- Spherical equivalent on distance subjective refraction between -0.50D and -2.50D.
- Astigmatism ≤ 0.75D
- Stable myopia. Maximum change in refraction of 0.50D in the last 2 years.
- Best corrected visual acuity of at least 0.00 logMAR (ETDRS chart).
- Thinnest pachymetry reading ≥ 440 μm.
Key exclusion criteria (3 listed)
- History of or current condition, disease, surgery or medication with ocular effects that could affect the outcomes of the treatment.
- Allergy to any substance or device used in the study.
- Cognitive insufficiency interfering with the informed consent.
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| 4.0 mm treatmentPiXL treatment with UV irradiation in a central 4.0-mm ring-shaped zone of the cornea. | Procedure or surgery | 4.0 mm zone |
| 3.5 mm treatmentPiXL treatment with UV irradiation in a central 3.5-mm ring-shaped zone of the cornea. | Procedure or surgery | 3.5 mm zone |
Primary outcome
Change from baseline in uncorrected visual acuity
Time frame: 1, 3, 6, 12 and 24 months after treatment
Change from baseline in distance uncorrected visual acuity
Change from baseline in spherical equivalent
Time frame: 1, 3, 6, 12 and 24 months after treatment
Change from baseline in spherical equivalent on subjective distance refraction
2 secondary outcomes
Change from baseline in corneal endothelial cell density
Time frame: 12 and 24 months after treatment
Change from baseline in best corrected visual acuity
Time frame: 1, 3, 6, 12 and 24 months after treatment
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 10 Dec 2020.
- Individual participant dataSharing planned: No
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Anders Behndig, MD, PhD principal investigator
Department of Clinical Sciences/Ophthalmology, Umeå University, Umeå, Sweden
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing 4.0 mm treatment and 3.5 mm treatment in people with Myopia and Corneal Crosslinking, run by Umeå University at 1 site in Sweden.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 7 inclusion and 3 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 10 Dec 2020. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Sweden. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Change from baseline in uncorrected visual acuity (time frame: 1, 3, 6, 12 and 24 months after treatment). The study lists 2 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 10 Dec 2020; AzTrials last refreshed its copy on 8 Nov 2026.