The macula is responsible for all our central vision, most of our colour vision and the fine detail of what we see, so although macular holes are typically smaller than a pinhead, they can cause a substantial loss of sight. Macular holes affects around 3 in 1,000 people over the age of 55 and are more common in women than men.
What causes macular hole?
Our eyeballs are filled with a jelly called “vitreous humour”. As we get older, this jelly shrinks and pulls away from the retina at the back of the eye. This process is called posterior vitreous detachment (PVD) and for most people it is harmless. However, for others, the vitreous humour sticks to the retina. As it shrinks, the jelly pulls off a bit of the retina, leaving a hole.
What are the symptoms?
In the early stages you may notice distortion, blurred vision, straight lines appearing wavy and reading becoming difficult. Late symptoms include gaps in your central vision. Nine times out of ten it will only affect one eye, so you may not notice sight loss immediately. Macular holes do not affect peripheral sight but the sooner they are treated, the more sight you are likely to regain.
If you suddenly see flashing lights or floaters, or notice your vision fading, you should seek urgent medical help as this can be a sign of retinal detachment.
Some macular holes can seal themselves and do not require any treatment. Alternatively, you may be offered a one-off injection, however, this treatment is not effective for everyone and has a number of side effects, including floaters and disturbance of colour vision.
Vitrectomy surgery is successful in repairing macular holes 90 per cent of the time, and nine out of ten people will see their vision improve. A tiny cut is made in the eye and the vitreous gel is replaced with a bubble of gas. To begin with, the bubble will block your sight, but it is naturally absorbed over several weeks.
One common side-effect of this treatment is cataract: within two years of a vitrectomy, most people will need cataract surgery. If you need a vitrectomy, you may be offered cataract surgery at the same time, if you have not already had it.
After surgery, you may be asked to lie face-down for several days (called “posturing”) to help the eye heal properly.
Researchers are looking at ways to make the surgery even more effective, such as using silicon oil instead of a gas bubble. They are also investigating how long people might need to “posture” for to gain the best results. Clearer images of the retina mean you can now have a better idea of how much of your vision you might regain after surgery.