Skip to main content


My main research interests range from visual fields to understanding the molecular organisation of fibrous proteins, in particular that of collagens forming networks and that of the proteins in the muscle sarcomere.

Perimetry is a powerful tool, in association with others, for the diagnosis and assessment of many eye conditions including maculopathies, optic neuropathies and intra-cranial lesions. I am particularly interested in the ocular toxicity of the anti-epileptic drug vigabatrin. Although an extremely effective drug at containing the symptoms of epilepsy, it is associated with irreversible visual field loss. In collaboration with Professor John Wild, I am developing a staging system to recognise and characterise vigabatrin associated visual field loss, which should prove fundamental in managing patients treated with the drug (

Network forming collagens do not form fibrils, but their general role appears to be to provide both mechanical strength and filtering properties. In some cases the open networks that they form are ordered enough that their structure can be analysed both by X-ray diffraction and by electron microscopy to reveal the basic molecular packing arrangements. I have taken advantage of the remarkably good order in the network-like structure of the egg case walls of the dogfish to reveal an open, body-centred, collagen molecular assembly. Intriguingly, something similar to this has been found in the human eye associated with a condition known as full thickness macular holes. In this case it appears to be collagen Type VI that is forming the aggregates. I am continuing to explore the nature of such collagen aggregates in the eye, especially in relation to Sorsbys Fundus Dystrophy and Age-Related Macular Degeneration. I also carry out theoretical analyses of collagen amino acid sequences to try to understand the general principles that link collagen structures and functions.

The cornea is another system where collagen is organised as a network that possesses incredible optical properties. My aim is to understand which physical mechanisms are responsible for this organisation and how corneal optical properties arise. At present we are pursuing this by means of three-dimensional electron microscopy.

In collaboration with the Cell Signalling and Cell Biology Section at the University of Bristol, I am studying the ultrastructure of the myosin and actin filaments using X-ray fibre diffraction. In particular, we are following dynamic molecular changes in active muscle by means of fast (millisecond) time-resolved X-ray diffraction using very powerful X-ray beams from synchrotron X-ray sources, particularly the Advance Photon Source, at Argonne National Laboratory, in the US.
















Book sections


Why are corneas transparent?

Mammalian corneas, like much of the extracellular matrix, are made essentially of collagen and proteoglycans. However, unlike the rest of the extracellular matrix, they are exquisitely transparent. To understand why we need first to understand how light interacts with each collagen fibril in the cornea.


Lewis PN, Pinali C, Young RD, Meek KM, Quantock AJ, Knupp C. (2010) Structural interactions between collagen and   proteoglycans are elucidated by three-dimensional electron tomography of bovine cornea.
Structure. 18(2), 239-245.

Knupp C, Pinali C, Lewis PN, Parfitt GJ, Young RD, Meek KM, Quantock AJ (2010) The architecture of the cornea and structural basis of its transparency.
Advances in protein chemistry and structural biology,78, 25-49.