For our first post of 2023 I thought I'd make it a clinical one and talk a little about an eye disease that everyone has heard of but not many know what it actually is - Glaucoma.
Now Glaucoma is a little tricky to even explain what it is, there are a few different types of Glaucoma (or "the Glaucomas") which makes it even more difficult. But here goes!
What we would class as “normal” Glaucoma is usually characterised by a high pressure within the eye which will damage the nerves of the back of the eye well it will actually damage the blood supply to the nerves of the back of the eye resulting in nerve loss and therefore damage to the optic nerve and loss of the visual field which is our peripheral vision or what we can see around us. I can talk about other types or subsets of Glaucoma another time.
So what do we actually do to look for glaucoma in an eye examination? Well first of all we've all had the old pressure test which is usually a puff of air in most High Street opticians. Admittedly, it's not the most pleasant of experiences but it doesn’t hurt and it’s an essential way of checking the pressure within the eye. If the pressure is high, that could be a sign of Glaucoma. Next we look at the nerve had to decide if the optic nerve itself looks healthy and to see if there any signs of Glaucoma. Then the third thing we normally do is the visual field test - which is checking just how much you can see around you in that peripheral part of the vision that could be damaged.
We've been doing these tests for many years - probably using the same sort of methods for 40 or 50 years now, yes, the machines to do these tests have improved over time and we are better than ever at finding and diagnosing Glaucoma with them but what I really want to mention today is the improvements that have come forward in technology. We can now scan through the layers of your retina with an OCT scan and look at the nerve cells to check for Glaucoma. We now know that certain nerve cells are going to be damaged first in Glaucoma, there's a layer of cells called ganglion cells which are going to be the first to go and these new modern scanners can check the ganglion cell layer and see if these are shrinking over time, now that is invaluable in checking for Glaucoma. Next, we are going to scan around the top of the optic nerve where we're going to look at the thickness of the nerves that are coming into the optic nerve and again if these nerve cells are thinning that could be due to Glaucoma. Because we can measure the thickness of these nerve cells these modern OCT scans can actually detect Glaucoma, in some cases, years before the traditional methods. For example, visual field checking - you're only going to see a problem with peripheral vision once the damage has started so these new scans can to help protect and preserve sight for the future.
So my advice to you is if someone is offering you an OCT scan have it. It's the best way to look for Glaucoma and this is especially important for anyone who has a family history of Glaucoma, if you can have these scans and build up a picture over time looking for any changes in the nerve layers, then all the better. I hope this does help you make a decision about having scans in the future, I would always highly recommend it to everybody not just those with a family history of Glaucoma; it's definitely worth it for everyone!