Miss Stephanie Campbell
Research Topics and Related Projects:
This PhD project aims to characterise the Down's syndrome (DS) cornea clinically and biomechanically and investigate why the ectatic condition 'keratoconus' seems to be more prevalent in this group. Keratoconus causes a thinning and protrusion of the paracentral cornea, generally asymmetrically bilateral, appearing in the second or third decade and may progress until useful vision in that eye is lost.
Patients who have DS are unlikely to report early changes in vision both because of their communicative limitations, and because the DS visual system is inherently less sensitive than that in typically developing young people. It is for this reason that keratoconus is often not diagnosed until the disease process is well established, with vision already affected and irregular astigmatism present to the extent at which it cannot be corrected with spectacles.
The social detriment of vision loss for an individual with DS is profound. Since sensory impairments of hearing and motor control are common in this group, compounded visual loss has a dramatic impact upon communicative ability and quality of life. With the advent of collagen crosslinking (CXL), the opportunity is now available to provide early treatment to stabilise the cornea and prevent progression of the disease, in a less invasive and less risky procedure.
Often patients with DS do not present in clinics with keratoconus until it is in its moderate to late stages, when the window for CXL therapy had passed. The new CXL therapy requires a minimal residual corneal thickness of 400 microns, but since the DS cornea is typically 15-20% thinner than normal, the window for monitoring for change is much smaller than usual.
One goal of this project is to provide clinical diagnostic guidelines with an aim to early diagnosis, and subsequent early treatment of the disease. Such early treatment has previously not been available on the NHS via NICE guidelines until Autumn 2013, so it really is a very relevant and exciting time indeed.
Victor Tybulewicz, National Institute for Medical Research: use of Down’s syndrome mouse model
Nikki Hafezi, Light for Sight, Geneva: Collagen cross-linking for keratoconus in Down’s syndrome