A Quantitative Index that Characterizes Optic Nerves at Risk of Glaucoma
Discs at Risk: Novel Optic Nerve Head Phenotyping in Glaucoma
The lamina cribrosa is a structure in the optic nerve that is altered in glaucoma, resulting in vision loss. The aim of this project is to identify early signs of changes in lamina cribrosa integrity before nerve fibers are damaged and vision is lost. These signs will be used to determine a novel quantitative index that will be used to determine which optic nerves are at risk of developing disease.
Glaucoma can be difficult condition to detect in the earliest stages, and it is vital that treatment is given as soon as possible to prevent further damage to the eye. Clinical instruments are available to examine the optic nerve head which aim to detect the presence of glaucoma and to monitor its progression. These machines are able to examine the front surface of the optic nerve head, but only a few are able to provide information on what is happening below the surface. Important changes occur under the surface of the optic nerve head in glaucoma and Drs. Julie Albon, James Morgan, Rachel North, Wolfgang Drexler, Michael Girard, and colleagues will use a new machine (a novel type of optical coherence tomography or OCT), which is able to examine both the front surface and parts below the surface in detail. As the optic nerve leaves the eye, it travels through holes (or pores) in the lamina cribrosa. In glaucoma there are changes to these pores and the shape and structure of the lamina cribrosa. Detecting these changes could be an important sign that glaucoma is developing or getting worse. Currently it is not possible for your eye doctor to examine the lamina cribrosa. Dr. Albon and colleagues will develop methods to analyze these changes in the lamina cribrosa so that as the novel technology becomes more available, researchers and eye doctors will be able to detect more rapidly changes to the optic nerve head due to glaucoma.
Dr. Albon and colleagues have been working with a novel imaging device, a type of "optic coherence tomography" or "OCT," which produces highly detailed images or pictures of important structures which lie under the surface of the optic nerve. As glaucoma progresses, potentially damaging changes occur within these important structures. One of these structures is called the lamina cribrosa (LC). The optic nerve fibers leave the back of the eye via the LC to take messages to the brain to be interpreted into vision. The LC is a sieve-like structure with a series of holes or 'pores' through which the bundles of optic nerve fibers pass as they leave the eye.
Dr Albon and colleagues are using OCT to view the detailed structure within the lamina cribrosa, which has not been possible to do in the clinic before now. This team has been using this novel OCT to take three dimensional images of the back of the eye of people with healthy eyes and of people with glaucoma. From these images, the changes in the glaucomatous LC, compared to those with healthy eyes, can be found and documented. Dr. Albon’s team is working to develop new methods to analyze and interpret these images, so that more is understood about how the LC alters in glaucoma. The new analysis methods will be used to supplement the findings of current clinical tests to aid in the detection and monitoring of glaucoma.
About the Researcher
Dr. Julie Albon is a lecturer in the Visual Neurscience and Molcular Biology Group at the School of Optometry and Vision Sciences in Cardiff University. Following her degrees in Applied Biological Sciences, she completed her Ph.D. in the University of Bristol studying age-related changes in the connective tissue of the human lamina cribrosa. Her research team is now focusing on understanding the connective tissue, cellular and structural changes that occur in the aging process, and glaucoma to identify what makes an optic nerve susceptible to the development of glaucomatous optic neuropathy.
Mortlock KE, Flynn B, Tumlinson A, Fergusson JR, Povazay B, Drexler W, Morgan JE, North RV, Albon J (2012) Three Dimensional (3D) Segmentation of normal and glaucomatous optic nerve heads in 1050nm optical coherence tomography (OCT) datasets. ARVO Meeting Abstracts 53:2142.
First published on: July 6, 2011
Last modified on: March 22, 2013