Changes in Corneal Thickness in Keratoconic Eyes With Variation in Scleral Contact Lens Central Clearance
试验速览
- 阶段
- 不适用
- 入组人数
- 40
- 试验地点
- 1
- 主要终点
- Corneal Thickness
研究概览
简要总结
The purpose of this study is to investigate changes in the corneal thickness of scleral contact lens wearers in a keratoconic (KC) population and compare to age-matched controls. The hypothesis is that scleral contact lens wear is associated with low levels of corneal hypoxia including measurable changes in corneal thickness. Corneal thickness will be altered post scleral lens wear compared to pre-lens wear and the amount of alteration will correlate to the fitting characteristics in the central zone of the scleral lenses. We propose to take a sample of keratoconic and control participants, fit them in scleral lenses, and to measure topographic corneal thickness after 8-10 hours of scleral lens wear after three weeks of wear, to compare two instruments in the measurement of corneal thickness, and to compare the effects of varying central corneal clearance of the scleral lens on corneal thickness.
详细描述
The purpose of this study is to investigate changes in the corneal thickness of scleral contact lens wearers in a keratoconic (KC) population and compare to age-matched controls. The hypothesis is that scleral contact lens wear is associated with low levels of corneal hypoxia including measurable changes in corneal thickness.
This will be a prospective, dispensing study design. The study will involve up to 20 keratoconic participants and up to 20 age matched controls. Participants will attend 1 screening/fitting visit wearing their habitual contact lenses where the two test lens designs (350 and 450microns) will be fitted. There will then be a delivery visit for each design (randomly selected) and a single follow up visit after 8-10 hours of scleral lens wear, three weeks later. A washout period of a minimum of 48 hours will be applied between the cross-over of each lens design. Lenses to be worn in this study will be made of Boston XO material and are approved by Health Canada. The lenses will have a diameter of 14.8-17.0mm with a high and low sagittal depth in the corneal zone. As to which of the two lenses is being assessed, both the investigator and the participant will be masked as the assistant will provide the lenses in an unlabeled case. Masking the investigator will prevent bias when measuring corneal thickness and analyzing the data. The objectives of this study are to take a sample of keratoconic and control participants, fit them in scleral lenses, and to measure topographic corneal thickness after 8-10 hours of scleral lens wear after three weeks of wear, to compare two instruments in the measurement of corneal thickness, and to compare the effects of varying central corneal clearance of the scleral lens on corneal thickness. Secondary objectives include comparing ocular physiological outcomes between the two test lens designs. Corneal thickness will be altered post scleral lens wear compared to pre-lens wear and the amount of alteration will correlate to the fitting characteristics in the central zone of the scleral lenses.
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
- Double (Participant, Investigator)
入排标准
- 年龄范围
- 18 Years 至 —（Adult, Older Adult）
- 性别
- All
- 接受健康志愿者
- 是
入选标准
- •(Test Group):
- •Had been diagnosed with keratoconus in at least one eye.
- •Is at least 18 years of age and has full legal capacity to volunteer.
- •Has read and understood the information consent letter.
- •Is willing and able to follow instructions and maintain the appointment schedule.
- •Inclusion Criteria (Control Group)
- •Had been NOT diagnosed with keratoconus in at least one eye.
- •Is at least 18 years of age and has full legal capacity to volunteer.
- •Has read and understood the information consent letter.
- •Is willing and able to follow instructions and maintain the appointment schedule.
排除标准
- •(Test Group):
- •Is using any topical medications that will affect ocular health.
- •Has any ocular pathology or severe insufficiency of lacrimal secretion (severe dry eyes) that would affect the wearing of contact lenses.
- •Has persistent, clinically significant corneal or conjunctival staining using sodium fluorescein dye.
- •Has any clinically significant lid or conjunctival abnormalities and active neovascularization.
- •Is aphakic.
- •Has undergone penetrating keratoplasty.
- •Is participating in any other type of eye related clinical or research study.
- •Has any known allergies or sensitivity to the diagnostic pharmaceuticals or products, such as fluorescein, used in this study.
- •Exclusion Criteria (Control Group):
- •Is using any topical medications that will affect ocular health.
- •Has any ocular pathology or severe insufficiency of lacrimal secretion (severe dry eyes) that would affect the wearing of contact lenses.
- •Has persistent, clinically significant corneal or conjunctival staining using sodium fluorescein dye.
- •Has any clinically significant lid or conjunctival abnormalities and active neovascularization.
- •Is aphakic.
- •Has undergone any corneal surgery.
- •Is participating in any other type of eye related clinical or research study.
- •Has any known allergies or sensitivity to the diagnostic pharmaceuticals or products, such as fluorescein, used in this study.
研究组 & 干预措施
Keratoconics wearing ZenLens with high central clearance
Scleral contact lenses designed to provide approximately 450 microns of central clearance.
干预措施: ZenLens™ (Device)
Keratoconics wearing ZenLens with low central clearance
Scleral contact lenses designed to provide approximately 350 microns of central clearance.
干预措施: ZenLens™ (Device)
Healthy controls wearing ZenLens with high central clearance
Scleral contact lenses designed to provide approximately 450 microns of central clearance.
干预措施: Zen™ RC (Device)
Healthy controls wearing ZenLens with low central clearance
Scleral contact lenses designed to provide approximately 350 microns of central clearance.
干预措施: Zen™ RC (Device)
结局指标
主要结局
Corneal Thickness
时间窗: 6 weeks
Corneal thickness after 8-10 hours of scleral contact lens wear will be measured with the Spectralis OCT and Oculus Pentacam
次要结局
- Conjunctival redness(6 weeks)
- Tear biochemistry: cell count(6 weeks)
- Tear biochemistry: proteases and cytokines(6 weeks)
- Visual acuity(6 weeks)
- Corneal and conjunctival staining(6 weeks)
研究者
Luigina Sorbara
Associate Professor
University of Waterloo