Clinical Trial Details
— Status: Completed
Administrative data
NCT number |
NCT03197272 |
Other study ID # |
PiXLMYOP-I |
Secondary ID |
|
Status |
Completed |
Phase |
N/A
|
First received |
|
Last updated |
|
Start date |
April 21, 2016 |
Est. completion date |
November 30, 2020 |
Study information
Verified date |
December 2020 |
Source |
Umeå University |
Contact |
n/a |
Is FDA regulated |
No |
Health authority |
|
Study type |
Interventional
|
Clinical Trial Summary
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.
Description:
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.