Scleral vs Corneal RGP contact lenses in irregular cornea disorders
Research type
Research Study
Full title
A randomised controlled research to compare the visual quality, clinical performance and effect on vision related quality of life of Rigid Gas Permeable (RGP)Scleral contact lenses to Corneal RGP contact lenses in participants with Keratoconus and other Irregular Cornea disorders (IC)
IRAS ID
162888
Contact name
Alexander Levit
Contact email
Clinicaltrials.gov Identifier
Clinicaltrials.gov Identifier
N/A, N/A
Duration of Study in the UK
2 years, 0 months, 1 days
Research summary
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 for irregular cornea in hospital contact lens practice are Keratoconus (kc) and related cornea thinning disorders. These conditions cause mild to marked impairment of vision due to corneal irregularity which degrades 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.
Ideally corneal lenses should fit in alignment over a large area of a normal cornea, in keratoconus corneal lenses commonly bear on the cone area of the cornea. This lens 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 (VQoL)compared to wearers who have no KC.
In cases where corneal lenses are not well tolerated, cause corneal insult, reduced visual performance or poor physical fitting, the large diameter Scleral RGP contact lenses (scleral lenses) may be used as a problem solver. Unlike the corneal lenses, scleral lenses completely bridge over the cornea and stabilise by evenly distributing their weight on the tough and insensitive sclera (the white part of the eye).
The aim of this research is to investigate the performance of scleral lenses in participants with irregular cornea who habitually wear corneal lenses and compare the performance of both contact lens types.
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?REC name
London - Camden & Kings Cross Research Ethics Committee
REC reference
15/LO/1067
Date of REC Opinion
31 Jul 2015
REC opinion
Further Information Favourable Opinion