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Technology has moved on and we now use much smaller instruments in the eye. This is surgery carried out with 23Guage instruments and the smaller size means the guillotine part of the vitreous cutter is very close to the edge and so can be used just on top of the retina. This is my preferred method of delamination now. (Delamination means separating tissues)The aim of surgery is to remove the gel which is pulling the retina off the wall of the eye resulting in loss of vision. At its worst the retina totally detaches and all sight is lost and the eye becomes painful as well as blind. Thankfully this is rare these days with good screening and effective laser treatments. In this video I start over the macula and clear the gel to gain access to the retina. I then remove all the traction and folds through the macula with an ILM Peel. Remember the macular is the only part of the retina we can see detail with. From here I move outwards to separate all the attachments of the gel from the retina. It is challenge to free up connections to remove the gel and once the edge of the gel is found I keep moving round to free it to ensure no gel is left. Surgery went well and was carried out nder a local anaesthetic with the patient feeling no pain.
How does diabetes effect the eye?
It is all about supply and demand and a help signal. The eye is lined by a light sensitive tissue, the retina. This is just like the film in a camera except it is a very hungry tissue and needs lots of nutrients to work. The nutrients are brought in by blood vessels. All is well.
Diabetes causes two problems, it causes the blood vessels to leak and to block. Leakage is not a problem unless the leakage happens at the centre of the retina, the macula. The centre of the macula has a dip, the fovea, and this is the only part of the retina that enables you to see detail. Just try looking at a clock and then look 1m to the side and try to read the numbers, you cannot. If fluid leaks at the centre the retina does not work as well and the vision drops. This is the most common cause of poor sight in diabetes and treatment is very difficult. We use lasers and injections.
If the blood vessels block then, unlike the leakage, you will not notice a thing at first. The hungry retina does not get enough nutrients and so starts to call for help and this help signal is spelt VEGF (Vascular endothelial growth factor). VEGF causes blood vessels to grow. You (and the retina) may think this is a good idea but it is disasterous and if left alone results in a painful blind eye. The blood vessels are hopeless, they bleed and grow in all the wrong places including on the coloured part of the eye and on the surface of the retina and into the Jelly of the eye. Once they have grown onto the jelly they can bleed into the jelly causing vitreous haemorrhage and loss of sight and more worryingly, after they bleed they scar and then, as all scars do, they contract pulling the retina off the wall of the eye (Retinal detachment) causing loss of sight. Blood vessels that grow over the coloured part of the eye can prevent drainage of fluid from the eye causing a very high pressure and loss of sight.
What can be done?
Firstly it is essential that you achieve excellent blood sugar control and blood pressure control. If you smoke, stop. For the leakage, gentle laser can be applied and now a variety of injection treatments also used to treat macular degeneration are available, the so called 'anti-VEGFs' (Avastin, Lucentis) and sometimes steroid. The laser is painless and its main aim is to halve your chances of loosing three lines of vision on the test chart.
I mainly get involved on the surgical side of diabetes where the retina is detaching as a result of scar tissue pulling the retina off. Surgery is done under a local anaesthetic and is completely comfortable. If you wanted to have some 'chemical courage', sedation can be given to relax you. The jelly is removed by vitrectomy where a tiny guillotine cuts the jelly into fragments 5000 times a minute and then sucks them away. The eye is kept inflated by a salty drip. This surgery is the most challenging we do as it is difficult to predict what will need to be done until we get into the eye. The aim of surgery is simple, to separate the Jelly from the retina, close any holes or tears and support the retina whilst it settles. Surgery is difficult because it can be very difficult to get between the jelly and the retina and the retina is very thin and liable to tear.
Sometimes surgery is much more straightforward. If the Jelly has detached but caused a bleed in the eye, the blood stained jelly can be removed and more laser applied to the eye and risks of surgery are less but still include a 3% risk of retinal detachment and it is very likely that a cataract (clouding of the lens) will develop over a couple of years.
Should I have it done?
Nobody jumps out of a second floor window, If a Lion walked into the room most would jump! The decision for surgery varies from no real choice to a decision that could go either way depending on your approach to and understanding of risk. Generally indications for surgery are coming down as technology improves and surgery becomes safer. It was always said that if the retina is coming off at the centre or if bleeding is not going away then an operation was necessary. Many surgeons will offer surgery before this time in order to prevent the risk of advanced disease. Each decision is individual! We will make it together.