Squint/Strabismus Surgery

Squint, Deviation or Misalignment of Eyes and their surgical management

What is a squint?
A squint (strabismus) is when the eyes are not looking in the same direction, i.e. the eyes do not appear straight. The squint can be there all the time or just some of the time, such as when the eyes are tired.

What are the main types of squint?
It is mainly divided in two groups: Phoria (Hidden Squint) A binocular vision problem. This is a tendency for one eye to move horizontally or vertically away from the point of focus. Phoria can cause discomfort and headaches associated with the use of the eyes at distances, close up, or both. Some patients with phorias will see double when they get tired. Phoria can be detected with a cover test. Tropia( Manifest squint) is defines as manifest squint which is obvious all the time. An eye may turn in (convergent squint) or out (divergent squint) or one eye can be higher or lower than the other (vertical squint). A squint might be in one eye or swap between the eyes.

What is Squint surgery?
Squint surgery is a time-honored method to correct eye misalignment. It is the procedure of choice for some types of squint, for children and for those who dislike undergoing surgery while awake.

What are the expected benefits of the operation?
Squint surgery is carried out for different reasons. The surgeon will discuss them with you when your child is listed for surgery or at the pre-assessment.

The main goals of squint surgery are:

• Change the position of the eye(s)
• Reduce double vision
• Reduce an abnormal head posture (tilt, face turn, chin up/down etc.)

What are the main advantages of Squint Surgery?
Advances in strabismus surgery now provide benefits to most adults as well as children. Treating adults with strabismus can help improve depth perception (3D vision) and enlarge the field of vision. Most patients report improved self-esteem, communication skills, job opportunities, reading and driving after squint surgery. Alternatives to strabismus surgery are available for some patients, such as prism glasses, botulinum toxin injections or special contact lenses. Your consultant will discuss all option at the time of listing for surgery. Do not hesitate to ask for further clarification if needed.

What happens before the operation?
Once an operation date has been arranged, your child will be given a date to come in for pre-operative assessment by the anesthetist. The concerned doctor will ensure that your child is fit for surgery and will advise you about how to prepare for the surgery.

What happens on the day of surgery?
Please bring your child to our Eye Centre on time. Your child will be having a general anesthetic on the day so they should not eat or drink anything from midnight, otherwise the operation will be cancelled. Your surgeon will see yourself and your child on the day of surgery for a final review and signing the consent form.

What happens during the operation?
During the operation your child will be asleep. The surgery will involve tightening up, slackening off or moving some of the 6 muscles around the eye to a new position. The eye is not removed during surgery. At the end of the procedure, the eye is patched with an eye pad.

How long will the operation take?
On average, it takes about 20 minutes per muscle. This figure depends also on the age of the patient, his/her tendency to bleed, the size and position of the eyeball and whether it is the first operation or not. Patients that have undergone squint surgery previously have more scarring around the muscles, making further surgery more difficult. At times, the surgeon has to deal with unexpected findings and this will prolong the operation time.

Will my child need to stay overnight?
No, unless your child feels unwell or vomits after the general anesthetic. Our patients are usually able to go home in the afternoon after they have had something to eat and drink.

What happens after my child leaves the hospital?
You might notice that your child’s pupils are bigger than usual and your child may complain of blurred vision – this is a common side effect of the drops used during the operation to minimise bleeding. The pupils will get back to normal in about 4-6 hours. Your child may also complain of some discomfort, it is normal to experience this due to the superficial sutures (“stitches”) used in the operation. These sutures may need to be removed later on. Your child will be wearing a patch over the operated eye for two hours. We avoid patching if your child has had surgery on both eyes, or we cover one eye only. You will be given eye drops to put in to your child’s eye(s) for 2 weeks and we will arrange a post-operative appointment next day after surgery. Please keep this appointment as it is very important to assess the position of the eye and to monitor the healing process. Do not worry if your child complains of double vision after the surgery; it is normal for this to happen as the brain adjusts to a new eye position. If your child does not mention double vision there is no need to ask.

When will my child be able to resume to normal activities?
Most children go back to school or to their usual leisure activities, including sports, one week after surgery. The only exception is swimming, which should be avoided for 4 weeks’ after surgery. Please bear this in mind when booking holidays after your child’s strabismus surgery (there is no contraindication to travelling, including flying). Your child can use their glasses as normal, watch TV, read etc. straight away, if they feel up to it. However, no contact lenses can be worn whilst the eye is still red. The eyes can remain red up to 8 weeks after surgery; however, this varies from each individual. If you are concerned and/ or your child is experiencing double vision which is troublesome or getting worse, please contact us.

What are the common problems after squint surgery?

Common problems after surgery are:

• Nausea: This is possible after general anesthetic. It can be relieved by medication.
• Pain: Pain and discomfort last for a few weeks and can be relieved by simple pain killers.
• Gritty eye sensation is usually caused by the sutures (stitches) and this settles after few weeks. Please stop your child from touching or rubbing the eye(s).
• Swelling: It is common to notice mild swelling of the area around the eyes. This usually lasts 1-2 months.
• Watering is very common for the first few weeks. Blood can be seen on the tissue when the eye is wiped.
• Allergic reaction to the eye drops: Drops should be stopped and a different type of antibiotic might be given.
• Blurred vision: This is common in the operated eye and it will usually improve over several weeks. New glasses can be required.
• Persistent visual problems: This surgery does not correct long standing visual problems from strabismus (“lazy eye”) or the cause of strabismus. Glasses and/or prisms may still need to be worn after surgery.
• Double vision: Some children may experience double vision while the brain adapts to the new alignment. The double vision usually disappears in a few days in children and up to a fortnight in young adults; in some patients it may persist even longer, come back or be permanent. Patients can usually learn to ignore one of the images. If not, prism glasses or may be prescribed.

Can there be any complications after squint surgery?
Surgery has risks. Occasionally a complication will arise from the surgery carried out. Complications can happen right away or days, months, even years later. The risk for complications is different for each person, and depends on how long your child has had the squint, whether they have already had surgery for strabismus previously, how well they heal, whether they have diseases of the eye or other parts of the body, and any medications.The major risks are listed:

• Under/over correction: this might improve with time. It takes at least two months for the results of the operation to become stable. Further treatment (special glasses, botulinum toxin injection, or more surgery) may be necessary. It might not be possible to achieve perfect alignment.
• Scarring: every operation causes scarring. It is usually present over the white portion of the eye and it can fade away with time. Usually it is not noticeable after some months. In rare cases, or if the eye has had more than one operation, the scarring might be severe and require further surgery.
• Change in eyelid position: this is not very common and it happens more frequently in older patients. Another operation might be needed to correct the lid position.
• Retained suture: this is a late reaction to a stitch, which is not fully reabsorbed and often needs to be removed.
• Change in focus of the eye: this means that you might need glasses or a change in your present glasses.
  Rarer complications such as infection, abnormal thinning of the eye (scleritis), lost muscle, retinal detachment and endophthalmitis may also occur occasionally.
• Loss of vision is another rare complication and this can result from an infection or damage to the retina.
• This operation is carried out under general anesthesia, which carries some risk. Your Anesthetist will discuss these risks with you before the operation.