Development of a Retinal Ganglion Model for Glaucoma
Other pages for this project
Basic Description of Glaucoma
Glaucoma is an ophthalmological condition characterised by increased intraocular pressure and retinal ganglion cell death. The resulting symptoms vary between the acute and chronic forms of the condition, but invariably eventuate in some level of vision loss if untreated (Elkington and Khaw, 1988). There are two major types of Glaucoma - each consisting of primary and secondary causes. Only the basic pathophysiology is covered below.
Acute Closed Angle Glaucoma
This type of glaucoma is predisposed to by old age and long-sightedness as well as a narrow anterior chamber (Elkington and Khaw, 1988). It occurs when in mid-dilation of the pupil, the iris adheres abnormally to the lens posterior to it. This prevents flow of the aqueous humour (produced by the ciliary body) from the posterior chamber of the eye (between the iris and the lens and including the ciliary body) to the anterior chamber (between the iris and the cornea). The build up of aqueoud behind the iris causes a anterior bulge which may contact the inner endothelial layer of the cornea. This may effectively block fluid drainage through the lateral Schlemm Canal. The build up of aqueous causes a rapid pressure increase characterised by pain, red eye, oedema of the cornea (causing a hazy cornea on inspection and a blue-green iris) and often the patient experience of seeing haloes around light sources. Such attacks of acute glaucoma may occur more frequently in the evening when the eye is more dilated, and may be relieved somewhat by sleeping - due to pupil contraction (Trevor-Roper, 1980).
Simple (or Chronic) Open Angle Glaucoma
This more chronic glaucoma is predisposed to in older diabetics and those with short-sightedness. It is different from closed angle glaucoma as the name suggests. In open angle glaucoma, there is no blockage of aqueous drainage through the Schlemm Canal. Whilst the pathology is not completely known, it is believed by some that age imparts a sclerotic process on the episcleral veins and upon the trabeculae in the Canal of Schlemm. This is believed to impair aqueous reabsorption and thus cause an increase in pressure. The effects however, are far more insidious than with closed angle glaucoma. Often there are no symptoms of red eye or pain. In open angle glaucoma, effects may occur over years, with the consequence that by the time the patient presents with vision loss, it is often irreversible (Trevor-Roper, 1980).
Retinal Ganglion Cells
There are many theories as to what processes and pathways induce the retinal cell ganglion apoptosis seen in glaucoma. Most theories centre around indirect and direct effects of increased intraocular pressure. See Literature Review Topics and Recommended References for more about the topics that will be covered in the literature review.
I am currently trawling through the literature. I have downloaded around 50 articles so far on the apoptotic mechanisms of retinal ganglion cells in glaucoma. This section will now be continued in Supervisor Meeting Minutes and Current Activities
- The following references will be amended once a particular style is decided upon for the literature review.
- I hope to add many more articles and references as I complete my literature review. They will be added on this page: Literature Review Topics and Recommended References
- Elkington, A.R. & Khaw, P.T. (1992). ABC of Eyes - a collection from articles published in the British Medical Journal. Published by the British Medical Association, London.
- Trevor-Roper, P.D. (1980). Lecture notes on Ophthalmology 6th edn. Published by Blackwell Scientific Publications.