An interventional study of PiXL in Myopia and Corneal Crosslinking, sponsored by Umeå University. Completed at 1 site in Sweden. Open to participants aged 18 Years to 35 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2020-12-11.
Sponsored by Umeå University · Not applicable, Interventional, and Treatment
To evaluate the improvement in myopic refractive error and the corneal endothelial safety with a corneal crosslinking treatment regimen for mild myopia. The treatment involves a 4-mm central treatment zone in high oxygen environment without corneal epithelial debridement.
The study is designed as a prospective, single-masked intraindividually comparing randomized controlled trial involving healthy volunteers ≥18 years of age of both genders with mild myopia, performed at the Department of Clinical Sciences / Ophthalmology, Umeå University Hospital, Umeå, Sweden. The study involves 23 persons with a myopia of -0.5 to -2.5 diopters (D) and astigmatism of ≤0.75 D. All participants are treated with phototherapeutic intrastromal corneal collagen cross-linking (PiXL) without epithelial debridement (epi-on), after topical riboflavin. For myopia of less than 1.0D, 10 J/cm2 will be used, for higher levels of myopia 15J/cm2 will be used, and the treatment involves continuous delivery of oxygen around the eye using an oxygen mask to achieve an oxygen concentration of ≥90% during treatment. Participants will be randomized to receive ultraviolet (UV) light according to PiXL Protocol A in one eye and PiXL Protocol B in the other, which is masked to the participant. Both eyes will be treated during the same visit.
Protocol A: UV irradiation in a central 4 mm homogenous zone of the cornea. Protocol B: UV irradiation in a central ring-shaped 4 mm area of the cornea. Patients are randomized utilizing a computer list of unique random numbers between 1 and 23; an even number will be treated with a homogeneous zone in the right eye; an uneven number with a homogeneous zone in the left eye. All patients are informed about the procedures and provide oral and written consent before inclusion in the study.
At baseline, before treatment, each eye is evaluated with slit-lamp examination, subjective refraction, determination of uncorrected (UCVA) and best corrected (BSCVA) visual acuities using the LogMAR fast protocol and intraocular pressure (IOP) using Goldmann applanation tonometry. Each eye is photographed using the "25 pictures" program with the Pentacam HR® (Oculus, Inc. Lynnwood, WA) under standardized, mesopic light conditions. Keratometry readings, central corneal thickness and the average corneal densitometry values (corneal light backscatter), expressed as standardized gray scale units, GSU) is determined with the Pentacam HR®. Central corneal endothelial photographs are taken with the Topcon SP-2000P specular microscope (Topcon Europe B.V., Capelle a/d Ijssel, the Netherlands), and the corneal endothelial cell count is calculated from a cluster of 25 cells from each photograph.
All the above mentioned investigations are repeated at 1, 3, 6,12 and 24 months after the treatment. At 1 week after treatment, UCVA is registered and a slit-lamp examination, a subjective comparison of discomfort and visual performance in each eye and an autorefractometer measurement are performed. One day after treatment the latter 3 examinations are performed.
984 studies on the registry are indexed under Myopia; 210 are open to participants now.
This study's enrollment of 23 is below the median of 80 across 783 interventional studies indexed under Myopia.
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Exclusion Criteria:
PiXL treatment with UV irradiation in a central 4 mm homogenous zone of the cornea. For myopia of less than 1.0D, 10 J/cm2 will be used, for higher levels of myopia 15J/cm2 will be used.
Procedure: PiXL
PiXL treatment with UV irradiation in a central ring-shaped 4-mm area of the cornea. A central 2-mm zone is left untreated, and the energy is higher towards the periphery of the ring-shaped area, reaching its maximum at 2 mm from the corneal centre. For myopia of less than 1.0D, a maximum of 10 J/cm2 will be used, for higher levels of myopia a maximum of 15J/cm2 will be used.
Procedure: PiXL
Phototherapeutic intrastromal corneal collagen cross-linking (PiXL) performed in a high-oxygen environment without corneal epithelial debridement, for treatment of mild myopia.
Change from baseline in uncorrected visual acuity
Change from baseline in distance uncorrected visual acuity
Time frame: 1, 3, 6 and 12 months after treatment
Change from baseline in spherical equivalent
Change from baseline in spherical equivalent on subjective distance refraction
Time frame: 1, 3, 6 and 12 months after treatment
Change from baseline in corneal endothelial cell density
Change from baseline in central corneal endothelial cell density
Time frame: 12 months after treatment
Plan to share: No
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This study is completed, as verified in Dec 2020. You cannot join it, but the record below documents what was studied.
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Umeå University