Adult squint (strabismus) surgery

A squint (strabismus) is a condition where the eyes are misaligned or crossed. One eye can turn in (convergent), out (divergent), up, or down. In adults, you might have had squint as a child, or it may come on later in life and cause double vision. Surgery may be recommended if there is a chance of restoring your ability to use the eyes together, to reduce double vision, or in improving the appearance of the two eyes. Surgery can be carried out at any age.

What does squint surgery involve?

While you are asleep under general anaesthetic, the surgeon will open your eyelids. They will not cut around the eye so there are no scars on the eyelids. On the white part of the eye (sclera) there is a layer like cling-film called the conjunctiva. When this is cut the surgeon can see the eye muscles. These muscles control the position and movement of the eyes. The surgeon will move these muscles to make them stronger or weaker.

Often in adults, the surgery will include using adjustable sutures. This means that when you wake up, the surgeon will put drops in your eye to numb it and measure eye position (as the orthoptist did before the operation). If the eye is over or under-corrected, the surgeon will be able to pull the stitch to get the eye position exactly right. This procedure is not painful, takes about 10 minutes and ensures the best possible result.

What to expect?

On the day

You will be admitted to your own private room and meet the anaesthetist and surgeon before the operation to answer any questions you may have. The surgery is usually carried out under general anaesthetic, which means you are asleep for the operation. It is common to wake up with an eye pad on one eye which you can remove the day after the operation. However, it will be taken off temporarily to check the position of your eyes if you are having adjustable surgery.

Most squint surgery is done as a day case operation, and takes on average about an hour. When you are awake and have eaten and drunk and been to the toilet you will be allowed home, usually three to four hours after the operation. We usually recommend someone escort you home, as you may still feel sleepy. You can stay overnight if you wish, or if it is deemed necessary.

After the surgery

After the operation, most people experience some discomfort, mainly a scratchy feeling, for a day or two. Normal painkillers like paracetamol are helpful in managing this. You will also be given some eye drops to put in for a couple of weeks afterwards to help healing and to prevent infection. The white of the eye will be quite red and this will take some weeks to fully settle, gradually fading.

We usually recommend about a week off work to recover, but you can use your eyes as normal straight away. You can drive after 24 hours if you do not have double vision and feel safe, though it is best to plan to take it reasonably gently initially. You can bath or shower the next day, although we recommend you try not to get soap or water in your eyes. Light exercise is fine, but it is usually recommended not to swim for four weeks after squint surgery.

Risks of squint surgery

Complications from squint surgery are rare. They may include over or under-correction of the squint, double vision (which may or may not settle), or very rarely an infection or inflammatory reaction, which would need further treatment. In rare cases, a further operation may be needed if, for example, the muscle were to slip. The risk to your sight is minimal (around one in 10,000) as the surgeon does not go inside the eye itself.

Some patients require more than one operation before their eyes appear straight – this is quite common if the squint is severe.

A general anaesthetic carries a very slight risk of complications.

Alternative treatments

Other treatments for squint may involve some or all of the following:

• glasses
• patching
• exercises
• prisms
• Botox injections.

An orthoptist (a health professional trained in visual development and eye movement) and ophthalmologist (a doctor trained in the diagnosis, treatment and prevention of diseases of the eye and visual system) can advise when surgery is appropriate.