A Randomised Controlled Research to Asses the Clinical Performance and Effect on Vision Related Quality of Life of Rigid Gas Permeable Scleral Versus Corneal Contact Lenses for Keratoconus and Other Irregular Cornea Disorders
试验速览
- 阶段
- 不适用
- 状态
- 已完成
- 入组人数
- 30
- 试验地点
- 1
- 主要终点
- Monocular Best Corrected Visual Acuity (BCVA)
研究概览
简要总结
The most common causes for irregular cornea (IC) in hospital contact lens practice are Keratoconus (KC) and related cornea thinning disorders. These conditions cause mild to marked impairment of vision and cannot be effectively corrected by spectacles and soft contact lenses. The gold standard in the management of KC is Corneal Rigid Gas Permeable contact lenses (corneal lenses), which correct approximately 90% of the corneal irregularity.
Compared with a normal cornea, the cornea in KC is irregular and this results in a compromise to the fit of rigid corneal lenses. Specifically, they bear on the cornea and this, together with the vulnerability of the cornea in KC, are implicated in corneal scarring, and disease progression as well as a significantly reduced vision related quality of life (QoL) in KC compared with corneal lens wearers who have no KC.
In cases where the compromise fit of corneal lenses proves problematic, large diameter Scleral RGP contact lenses (scleral lenses) may be used as a problem solver. Unlike the smaller corneal lenses which bear on the cornea, the scleral lenses completely bridge over the cornea and bear on the sclera.
The aim of this research is to investigate the performance of scleral lenses in KC participants who habitually wear corneal lenses.
The research question: is there a measurable difference in the visual performance and visual quality of life in participants with Irregular cornea disorders like keratoconus and other related conditions, who habitually wear corneal lenses in comparison with scleral lenses.
详细描述
The cornea is the transparent, fixed focus lens at the front of the eye. The cornea's curvature should be regular for good vision. The most common causes of irregular cornea (IC) in hospital contact lens practice are Keratoconus (KC) and related cornea thinning disorders. These conditions cause mild to marked impairment of vision due to High Order optical Aberrations (HOA), which degrade the retinal image quality and cannot be effectively corrected by spectacles and soft contact lenses. The gold standard in the management of KC are Corneal Rigid Gas Permeable contact lenses (corneal lenses), which correct approximately 90% of the corneal irregularity.
The corneal lenses fit differently in patients with a normal cornea compared to KC where they bear on the cornea. This fitting characteristic and the vulnerability of the cornea in KC are implicated in corneal scarring and disease progression as well as a significantly reduced vision related quality of life (QoL) in KC compared with corneal lens wearers who have no KC.
In cases where corneal lenses are not well tolerated, cause corneal insult, reduced visual performance or poor physical fitting characteristic, the large diameter Scleral RGP contact lenses (scleral lenses) may be used as a problem solver. Unlike the smaller corneal lenses which bear on the cornea, the scleral lenses completely bridge over the cornea and bear on the sclera.
The aim of this research is to investigate the performance of scleral lenses in participants who habitually wear corneal lenses.
Methodology The proposed quantitative experimental methodology is a randomised controlled trial (RCT) with cross over. The experimental intervention is a scleral RGP contact lens fitted from a fitting set and manufactured to exact specifications to optimise its physical fitting characteristics and optical performance. The control intervention is conventional design Corneal Rigid Gas Permeable contact lenses (corneal lenses). These lenses are considered the gold standard in the management of the visual disability caused by keratoconus and other IC disorders (Robertson, Cavanagh 2011).
研究设计
- 研究类型
- Interventional
- 分配方式
- Randomized
- 干预模型
- Crossover
- 主要目的
- Treatment
- 盲法
- Single (Investigator)
盲法说明
The practitioner who measures the visual outcomes is naive to the type of lens the participant is wearing
入排标准
- 年龄范围
- 18 Years 至 69 Years（Adult, Older Adult）
- 性别
- All
- 接受健康志愿者
- 是
入选标准
- •Diagnosis of keratoconus or related corneal irregularity
- •Age 18 years to 69 years.
排除标准
- •Good visual quality with soft contact lenses and or spectacles
研究组 & 干预措施
Scleral rigid gas permeable contact lenses
The experimental intervention is the Scleral Rigid Gas Permeable contact lens (SRGPcl), Zenlens™. These lenses are designed to bridge the cornea and fit in alignment with the sclera, thus avoiding any detrimental effects associated with corneal contact.
干预措施: Scleral rigid gas permeable contact lenses (SRGPcl) (Zenlens™) (Device)
Scleral rigid gas permeable contact lenses
The experimental intervention is the Scleral Rigid Gas Permeable contact lens (SRGPcl), Zenlens™. These lenses are designed to bridge the cornea and fit in alignment with the sclera, thus avoiding any detrimental effects associated with corneal contact.
干预措施: Corneal Rigid gas Permeable contact lenses (CRGPcl) (Rose K2) (Device)
Corneal rigid gas permeable contact lenses
The control intervention is the RoseK2™ Corneal Rigid Gas Permeable contact lens (CRGPcl). Corneal lenses are considered the gold standard in the management of the visual disability due to keratoconus and other related irregular cornea disorders.
干预措施: Scleral rigid gas permeable contact lenses (SRGPcl) (Zenlens™) (Device)
Corneal rigid gas permeable contact lenses
The control intervention is the RoseK2™ Corneal Rigid Gas Permeable contact lens (CRGPcl). Corneal lenses are considered the gold standard in the management of the visual disability due to keratoconus and other related irregular cornea disorders.
干预措施: Corneal Rigid gas Permeable contact lenses (CRGPcl) (Rose K2) (Device)
结局指标
主要结局
Monocular Best Corrected Visual Acuity (BCVA)
时间窗: Baseline and after a minimum of 6 weeks of wear of each contact lens type, report at study completion
High contrast BCVA will be measured by the specially constructed crowded, Logarithmic Minimum Angle of Resolution (LogMAR), Early Treatment Diabetic Retinopathy Survey (ETDRS) letter charts. An average score of 3 different, randomly presented charts will be taken as the final acuity score. It will be performed utilising the CSV1000E, under the established recommended standardised testing conditions utilised in a multitude of research protocols.
次要结局
- The final lens choice(At study completion after 6-12 months)
- Contrast Sensitivity Function(Measure at recruitment (Baseline), subsequent measurement after 6 weeks of wear, of lens 1 and 6 weeks of wear of lens 2. Study completion after 6-12 months.)
- The National Eye Institute-Visual Function Questionnaire (NEI-VFQ)(Measure at recruitment (Baseline), subsequent measurement after 6 weeks of wear, of lens 1 and 6 weeks of wear of lens 2. Study completion after 6-12 months.)
- The Levit Subjective Comfort and Vision Scales(Measure at recruitment (Baseline), subsequent measurement after 6 weeks of wear, of lens 1 and 6 weeks of wear of lens 2. Study completion after 6-12 months.)