Keratoconus
Conditions
Brief summary
In keratoconus (KC) corneal thinning and protrusion can cause myopia and irregular astigmatism, affecting vision. The biomechanical properties of the cornea is maintained by an intricate collagen network, which is responsible for its shape and function. In KC this collagen network is disrupted resulting in the cornea losing its shape and function. Keratoconic changes are focal and localised to certain regions of the cornea and the early detection of these changes is challenging. Screening methods include corneal topography (evaluation of anterior corneal surface curvature), tomography (assessing the morphological features of the anterior segment) and aberrometry (measuring the optical aberrations of the eye). More recent research suggests that the biomechanical destabilization of the cornea may precede topographic and tomographic evidence of KC. Management of KC depends on disease severity with severe cases being treated with keratoplasty and less severe cases with cornealcollagencrosslinking (CXL). CXL is an emerging technique, which aims to increase the biomechanical strength of the keratoconic cornea. Despite strong evidence of changes in the biomechanical properties in human corneas following CXL, there is a significant need for accurate measures of biomechanical changes in vivo pre and post CXL. Until recently technical limitations have restricted the ability to assess the biomechanical properties of the whole cornea in vivo. With the introduction of the CorvisST (Oculus) it is now possible to assess regional biomechanical behaviour of the cornea. The output from the device provides a variety of parameters to indicate the cornea's biomechanical strength. To date, the association between the deflection behaviours in various regions of the cornea in keratoconic eyes preand post CXL has not been studied. In order to effectively assess the clinical benefits of CXL such information is vital. The primary goal of this investigation is to investigate regional biomechanical properties of the keratoconic eye before and after CXL.
Interventions
PROCEDURECorneal Cross-linking
All participants recruited for the study will be scheduled for corneal crosslinking treatment
Sponsors
University of Plymouth
Study design
Observational model
COHORT
Time perspective
PROSPECTIVE
Eligibility
Sex/Gender
ALL
Age
18 Years to No maximum
Healthy volunteers
No
Inclusion criteria
* Adult subjects over the age of 18 with keratoconus who are enrolled for collagen crosslinking treatment
Exclusion criteria
* Any patient who has had surgical complications will also be excluded from participation in the study. Determination during enrolment: * Pregnancy or breastfeeding during the study * Any kind of systemic disease which affect collagen and the body water regulation system (Marfan syndrome, osteogenesis imperfect, pseudozanthoma elasticum, EhlersDanlos, diabetes, rosacea, acne, cardiovascular disease, thyroid disease)
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Change of the corneal hysteresis following corneal crosslinking (mmHg) | Up to 3 months prior to corneal collagen crosslinking treatment and at 3-6 months after treatment | Corneal hysteresis as measured using the CorvisST |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Axial Length prior to corneal crosslinking (mm) | Up to 3 months prior to corneal collagen crosslinking treatment | Axial length determined with the LenStar |
| Axial Length axial length following corneal crosslinking (mm) | At 3-6 months after treatment | Axial length determined with the LenStar |
| Change of refractive error following corneal crosslinking (LogMAR) | Up to 3 months prior to corneal collagen crosslinking treatment and at 3-6 months after treatment | Refractive error measured using objective refraction |
| Tear break up time prior to corneal crosslinking (s) | Up to 3 months prior to corneal collagen crosslinking treatment | Tear break up time determined using the Oculus K5 |
| Tear break up time following corneal crosslinking (s) | At 3-6 months after treatment | Tear break up time determined using the Oculus K5 |
| Change in corneal curvature following corneal crosslinking (mm) | Up to 3 months prior to corneal collagen crosslinking treatment and at 3-6 months after treatment | Corneal curvature assessed with the Pentacam HR |
Countries
United Kingdom
Contacts
Primary ContactPhillip Buckhurst, PhD
Backup ContactDaniela Oehring, MSc
Outcome results
None listed