Of all the conditions that I was taught to look for as a student, all those years ago, glaucoma stands out for the way that our understanding of its causes has changed so much over the years. As students we were taught a simple basic mechanical cause for the condition, which at the time was the basis for the treatments that were available. These consisted of eye drops that closed the pupil right down to a pin-hole and, if you also had cataracts, nearly obliterated your remaining vision. I had been in practice a little over a year when a new type of drop appeared on the market that didn’t close the pupil so much and was hailed as a major advance.
After about ten years I went to a refresher lecture by one of my erstwhile fellow students at University who had become an expert on glaucoma – this began: “Everything that we have taught you about glaucoma you should now forget – it isn’t like that at all”! Ever since then there has been a steady upgrading of our understanding about the condition, or more accurately collection of conditions, and consequently a steady improvement in our abilities to diagnose and treat them.
We have gone from “feeling” how hard the eye is (as taught in my student days) to measuring the pressure within the eye in ever more subtle ways involving resting a probe against the (anaesthetised) eyeball, then blowing at it with a puff of air and now bouncing a very light probe off the front of the eye – a procedure that amazingly is usually undetected by the patient. We have also gone from looking at the back of the eye in two dimensions using a very basic ophthalmoscope and guessing the contours of the optic nerve head (which is about two millimetres across) through ever-improving types of optical viewing devices to stereoscopic viewing and finally to 3D modelling using the OCT.
The advent of the OCT has revealed a whole new set of ways to look at the physical changes in the eye that accompany the onset of glaucoma and we are having to learn all over again new theories about exactly what is happening.
How this will change in the next forty years I cannot imagine – but that I suppose is the point of this article. As technology improves we get better and better understanding of the causes and best treatment for conditions, and long may it continue.
VAO have just received another boxful of over 200 old pairs of spectacles you donated, please keep on bringing them in.