Squints and Squint Surgery in Adults

Patient Experience

  • Reference Number: HEY-730/2023
  • Departments: Ophthalmology Department, Orthoptic
  • Last Updated: 31 May 2023


This leaflet has been produced to give you general information.  Most of your questions should be answered by this leaflet.  It is not intended to replace the discussion between you and the healthcare team, but may act as a starting point for discussion.  If after reading it you have any concerns or require further explanation, please discuss this with a member of the healthcare team.

What Is A Squint?

A squint is the common name for ‘strabismus’, which is the medical term to describe eyes that are not pointing in the same direction. A squint is sometimes called ‘lazy eye’.

The squint may be present all of the time or only some of the time. It may be in one eye only, both eyes, or may alternate between the two eyes. Squints can be present from childhood (congenital) or may develop in adulthood due to an underlying medical condition (acquired).

If you are diagnosed with a squint, glasses or prisms may be necessary. Sometimes surgery may also be needed.

What Is Squint Surgery?

Squint surgery involves adjusting the position of the eyes by moving the muscles on the outside of the eyeball (this does not involve removing the eye). Usually two muscles are adjusted, where one muscle is strengthened and the other is weakened. The surgeon may choose to operate on one eye or both eyes to achieve the best outcome. Your surgeon will discuss this with you at the time of consent. 

Why Do I Need Squint Surgery?

Surgery may be necessary to:

  • make the eyes look straighter (termed a rehabilitative case)
  • or to enable the eyes to work as a pair (termed a functional case)

The Ophthalmologist and Orthoptist will discuss this with you at the time of listing you for surgery, if you choose to go ahead.

You should be clear in your mind as to the purpose of the surgery. Surgery may or may not be the only option available to you; this will be discussed with you by your healthcare team.

Does It Matter If The Squint Is Not Treated?

Not all squints need an operation but a squint should always be assessed. Dependent on the type of squint you have, it may be causing you problems such as double vision, headaches, or concern due to the appearance of the eyes. Your Orthoptist and Ophthalmologist will give you advice on the options you have available in terms of your treatment. The options may include wearing glasses, the use of prisms, surgery or a combination of these treatments. The type of squint you have will determine the most appropriate treatment options available to you.

Can There Be Any Complications or Risks?

Squint surgery is very safe; complications are rare and in most cases can be treated effectively.

General Anaesthetic – The operation is performed under general anaesthetic and providing you are generally healthy, the risk of things going wrong due to the anaesthetic is small. Adverse reaction to the anaesthetic occurs in 1: 20,000.

Double Vision – There is a small risk you may develop double vision after the operation. This may clear up on its own if it does not, the Orthoptist will decide whether changing your glasses, prescribing prisms, eye exercises or further surgery is needed.

Cosmesis (straighten the eye for cosmetic reasons) – There is a risk the squint may be over or under corrected and sometimes further surgery is needed (approximately 20: 100 cases).

Infection – There is a very small risk of infection in the eye which can lead to loss of vision (1: 30,000)

Allergy – Some patients might have a mild reaction to drops prescribed after surgery. This results in itching / irritation and some redness and puffiness of the eyelids. It usually settles very quickly when the drops are stopped.

Redness and scarring – Your eye will be very red after the surgery. The redness in your eye and most of the scarring is not noticeable after three months. Occasionally, the eye does not completely return to its normal colour and mild visible scars may remain, particularly in cases of repeated operations.

Lost or slipped muscle. Rarely one of the eye muscles might slip back from its new position during the operation or shortly afterwards. If this occurs, the eye is less able to move around and, if severe, further surgery may be required. The risk of slipped muscle requiring further surgery is about 1: 5,000.

How Do I Prepare For The Squint Operation?

Your Consultant will discuss with you whether surgery is necessary in your case. When you see the Consultant, if you are in agreement, you may be offered a date for the surgery; it is more usual for you to be placed on the waiting list for surgery.

We will ask you to inform us at the earliest opportunity of any holiday arrangements that you may have already or if at a later date you make whilst you are on the waiting list. We would also ask you ensure we have your current telephone number and inform us of any change to this or your address.

You will usually be given about 2 weeks notice of the date of your surgery. You need to know that there will be a number of appointments we will need you to attend before and after the surgery date. You will be asked to attend for:

  • Pre-operative assessment – usually 1-2 weeks before the surgery date. You will see the Orthoptist and the doctor. Details of the surgery will be confirmed at this visit.
  • You will be required to visit the ward where you will have a general health check ensuring you are fit for surgery.
  • Date of the operation. You will receive detailed instructions when you attend for your pre-operative visit. You should not eat or drink at least 6 hours before the operation. You will need to arrive at the hospital early. The operation is usually a day case procedure but occasionally you may need to stay overnight.
  • It is advised you arrange for someone to collect you from the hospital rather than using public transport. You will not be able to drive yourself home.
  • Post-operative assessment. You will have an appointment to see the Orthoptist and the doctor 1-2 weeks after the operation.

It also important to plan that you will need to be off work for up to 2 weeks after the operation date and you will need to put drops in your eyes 4 – 6 times a day for approximately 1 week following the surgery. 

What Will Happen?

  • On the day you will need to arrive at the hospital early in the morning.
  • You will have an opportunity to speak with the Consultant and the Anaesthetist.
  • You will be undergoing general anaesthesia, which means you will be asleep during the operation. The operation will last between 40 minutes to 1 hour.
  • When you return from the theatre the eye that has been operated on will be covered with a cotton pad. The pad is there to prevent accidental rubbing of the eye and can be taken off later during the day.
  • The eye may be quite red, feel sore and be weeping. This is all normal. If you feel the eye is too painful the nurse will be able to provide pain relief.
  • Before you go home, you will be shown how to effectively bathe the eye and how to put drops into your eye. You will be given the number of the ward so you can contact them should you experience any problems following your surgery.

What Happens Afterwards?

  • When you are at home it is important that you follow the instructions given to bathe your eye and instill drops into your eye in order to prevent the eye from becoming infected.
  • You will need to avoid rough sports and swimming for at least 4 weeks following the operation. It is also important you avoid dirty, dusty environments for at least 2 weeks after the operation or until the eye has had chance to heal.
  • Most people feel well enough to return to work after 1-2 weeks. You may need to plan to take longer if you have a heavy manual job or need to work in a dirty, dusty environment.
  • You will need to attend a post-operative appointment. This appointment will be arranged for you and given to you by the team looking after you.

General Advice and Consent

Most of your questions should have been answered by this leaflet, but remember that this is only a starting point for discussion with the healthcare team.

Consent to treatment

Before any doctor, nurse or therapist examines or treats you, they must seek your consent or permission. In order to make a decision, you need to have information from health professionals about the treatment or investigation which is being offered to you. You should always ask them more questions if you do not understand or if you want more information.

The information you receive should be about your condition, the alternatives available to you, and whether it carries risks as well as the benefits. What is important is that your consent is genuine or valid. That means:

  • you must be able to give your consent
  • you must be given enough information to enable you to make a decision
  • you must be acting under your own free will and not under the strong influence of another person

Information about you

We collect and use your information to provide you with care and treatment. As part of your care, information about you will be shared between members of a healthcare team, some of whom you may not meet. Your information may also be used to help train staff, to check the quality of our care, to manage and plan the health service, and to help with research. Wherever possible we use anonymous data.

We may pass on relevant information to other health organisations that provide you with care. All information is treated as strictly confidential and is not given to anyone who does not need it. If you have any concerns please ask your doctor, or the person caring for you.

Under the General Data Protection Regulation and the Data Protection Act 2018 we are responsible for maintaining the confidentiality of any information we hold about you. For further information visit the following page: Confidential Information about You.

If you or your carer needs information about your health and wellbeing and about your care and treatment in a different format, such as large print, braille or audio, due to disability, impairment or sensory loss, please advise a member of staff and this can be arranged.

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