Comparison of a 4-mm Ring Shaped and 3.5-mm Ring Shaped PiXL Protocol for Low Grade Myopia
试验速览
- 阶段
- 不适用
- 状态
- 已完成
- 入组人数
- 27
- 试验地点
- 2
- 主要终点
- Change from baseline in spherical equivalent
研究概览
简要总结
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.
详细描述
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.
研究设计
- 研究类型
- Interventional
- 分配方式
- Randomized
- 干预模型
- Parallel
- 主要目的
- Treatment
- 盲法
- Single (Participant)
盲法说明
The participants are not aware which eye will receive the 4.0-mm ring-shaped zone treatment and which eye will receive the 3.5-mm ring-shaped zone treatment.
入排标准
- 年龄范围
- 18 Years 至 35 Years（Adult）
- 性别
- All
- 接受健康志愿者
- 是
入选标准
- •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.
排除标准
- •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.
结局指标
主要结局
Change from baseline in spherical equivalent
时间窗: 1, 3, 6, 12 and 24 months after treatment
Change from baseline in spherical equivalent on subjective distance refraction
Change from baseline in uncorrected visual acuity
时间窗: 1, 3, 6, 12 and 24 months after treatment
Change from baseline in distance uncorrected visual acuity
次要结局
- Change from baseline in corneal endothelial cell density(12 and 24 months after treatment)
- Change from baseline in best corrected visual acuity(1, 3, 6, 12 and 24 months after treatment)
研究者
Anders Behndig
Principal Investigator
Umeå University