The purpose of this study is to evaluate the efficacy, safety and postoperative ocular discomfort by individually customized Photorefractive intrastromal crosslinking (PiXL) without epithelium debridement in high oxygen environment (Epi-on) for progressive Keratoconus.
The study is designed as a prospective, open-label, nonrandomized 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 30 participants with unilateral Keratoconus, receiving Epi-on PiXL in high oxygen environment (n=30). All patients 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, extracted from Schemipflug camera measurements, Pentacam HR® (Oculus, Inc. Lynnwood, WA) and AS-OCT (Fourier domain OCT CASIA2, Tomey Technology and vision, Germany). Central corneal endothelial photographs are taken with the Topcon SP-IP specular microscope (Topcon Europe B.V., Capelle a/d Ijssel, the Netherlands) 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, 12h, 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, slit-lamp examination are evaluated.
Study Type
INTERVENTIONAL
Allocation
NA
Purpose
TREATMENT
Masking
NONE
Enrollment
32
After local anaesthetics, the keratoconus cornea is soaked in Riboflavin by repeated topical application during 10 minutes. 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 googles. The UV-dosage is individually customized based upon Kmax; for \< 45 Diopters (D) 7.2J/cm\^2 will be used; for 45-50D 10J/cm\^2 will be used; for \> 50D 15 J/cm\^2 will be used.
Umeå University Hospital
Umeå, Sweden
Uncorrected Distance Visual Acuity (UDVA)
Change from baseline in Uncorrected Distance Visual Acuity
Time frame: 1, 3, 6, 12 and 24 months after treatment.
Keratometry readings
Change from baseline in Keratometry readings, Kmean (average), K1 (flat meridian), K2 (steep meridian) and Kmax (steepest radius of curvature) assessed with the Pentacam HR Scheimpflug camera
Time frame: 1, 3, 6, 12 and 24 months after treatment
Subjective Ocular Discomfort Scores
Change in a Ocular Discomfort Visual Analogous Scale after treatment.
Time frame: 4, 8h and 1, 2, 3, 4, 5, 6 and 7 days after treatment.
Manifest Refractive Spherical Equivalent (MRSE)
Change from baseline in Manifest Refractive Spherical Equivalent
Time frame: 1, 3, 6, 12 and 24 months after treatment.
Corneal Endothelial cell density (ECC)
Change from baseline in corneal endothelial cell density
Time frame: 12 and 24 months after treatment
Best Spectacle Distance Visual Acutiy (BSCVA)
Change from baseline in Best Spectacle Distance Visual Acutiy
Time frame: 1, 3, 6, 12 and 24 months after treatment.
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