Macular Hole (Macular Cyst, Retinal Hole/Tear/Perforation)
A macular hole is a tiny opening in the macula, which is based in the middle of the retina at the back of the eye. The macula is a very important part of the retina; it sits at the back of the eye and when light floods into the eye, it passes through the cornea and lens and hits the retina. The retina contains cone and rod cells, which convert the light rays into electric signals that are then sent to the brain via the optic nerve. The macula has a high concentration of cone cells, which are used to process detailed images. Cone cells are predominantly used to produce colour vision and are involved in detailed activities, such as reading, watching television and sewing.
Macular holes usually only affect one eye but there is a 1 in 10 chance that both eyes will be affected. Macular holes are not identical to macular degeneration, which occurs when the macula becomes thinner and weaker over time.
What are the causes of a macular hole?
It is not fully understood why macular holes develop in some people and not others. As we get older the vitreous jelly can change and lose firmness, which may result in the vitreous humour part of the eye coming away from the back of the eye. In many cases, when the vitreous humour comes away from the back of the eye, this does not affect vision though it can cause floaters to develop.
In some cases the vitreous jelly remains connected to the back of the eye. But as it shrinks this can cause the macula to become detached from the retina, causing a macular hole. If aqueous fluid leaks into the hole this can cause blurred vision.
Symptoms of a macular hole
A macular hole is likely to affect central vision as this is generally controlled by the cone cells in the macula. When the central vision is affected, you may experience straight lines looking wavy and notice dots between horizontal and vertical lines. If the condition progresses you may experience a blank spot in your central vision. One of the first symptoms people notice is that they have increasing difficulty with detailed activities, such as reading and watching television. Symptoms usually vary according to the severity of the condition, which relates to the size of the hole and the layers of the eye that are affected.
Stages of a macular hole
There are three different stages of a macular hole. These are:
- Stage 1: Foveal detachment: in most cases early treatment can prevent progression.
- Stage 2: Partial-thickness hole: without treatment most cases of stage 2 macular holes progress to stage 3.
- Stage 3: Full-thickness hole: by this stage central vision will be severely affected.
How is a macular hole diagnosed?
If you experience symptoms or changes in your vision you should see an optometrist, who will examine your eyes and test your sight. If they suspect that you have a macular hole they will refer you to an eye specialist, called an ophthalmologist.
Treatment for a macular hole
In some cases the hole may seal independently, however, in the majority of cases surgery will be carried out. Surgery is usually performed under local anaesthetic, but in some cases general anaesthetic may be used. The aim of treatment is to prevent further damage to the eye and limit problems with sight. There are two key stages to treatment, with the first stage being surgery and the second stage is recovery.
The surgical procedure involves a surgeon using very small, delicate instruments to remove some of the vitreous jelly from the eye, as the removal of jelly allows space in front of the retina. Once there is enough space the surgeon will insert gas into the eye. The gas then floats upwards pressing the macula flat against the retina to seal the hole, which prevents further damage to the eye and the retina becoming detached from the back of the eye.
After the procedure
During the procedure it is common for the doctor to ask the patient to tilt their head downwards, which is to ensure that pressure is applied to the right part of the retina. This is known as posturing and patients are encouraged to adopt this position for a number of days to encourage the hole to heal. Posturing is important because the pressure from the gas must be placed on the right part of the retina in order for the macular hole to heal. If posturing is not done properly, this can cause the procedure to be unsuccessful. Your doctor will explain how long you need to posture for, but most recommend spending 50 minutes of every hour with your head down for a period of up to 7 days.
Tips for coping during the recovery period include:
- Sitting at a table.
- Leaning on a stool while sitting on a chair.
- Lying down.
As you will be restricted to what you can do around the house after the operation, it is a good idea to plan ahead and ask for somebody to give you a bit of help for a few days after the procedure. If you are panicking about housework, try to get as much done as possible before you have your operation and ask a friend or relative if they would mind helping out for a couple of hours a day during your recovery period. It is also a good idea to keep the things you need (for example, a radio, the telephone, tissues and a drink) close by so that you don’t have to keep getting up. You will not be able to travel abroad (by plane) for a period of time after the operation.
Risks of surgery
There are two main complications that can arise after surgery for a macular hole. These are:
- Cataracts: most people who have surgery for a macular hole develop a cataract. However, in most cases cataracts can be removed during a quick procedure.
- Retinal detachment (when the retina becomes detached): there is a risk that the retina can become detached from the back of the eye and if this occurs the surgeon will try to re-attach it as soon as possible.
Preventing a macular hole
It is not possible to prevent a macular hole, though attending regular eye tests (every 12 months if possible) will help to ensure that any problems are diagnosed and treated early, which will improve prognosis.