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Diagnostic occlusion

What is a squint?

A squint is a misalignment of the eyes where one eye appears straight and the other eye drifts in a different direction. This can happen intermittently or all of the time.

Some squints appear larger when looking into the distance or close up, while others are the same at all distances. For some children the squint becomes more noticeable when they are tired, ill, focusing on near objects, looking into the distance, daydreaming, or in bright sunlight.

What are the symptoms of a squint?

Children with a squint rarely complain of any problems, although some are conscious of when their eye is drifting. Occasionally, children may complain of double vision or are aware when their eye is drifting. This sometimes results in them closing one eye.

How is a squint treated?

There are a variety of treatments, depending on:

  • the type of squint
  • the underlying cause
  • the amount that the eye drifts
  • how often the eye drifts
  • how well a person can control their eyes

These include the use of glasses, exercises, and surgery to help straighten the eyes. Your orthoptist and ophthalmologist will advise which of these is appropriate for you.

What is diagnostic occlusion?

Diagnostic occlusion is the covering up of one eye with a patch for a period of time on the day of your next appointment.

What is the purpose of diagnostic occlusion?

By stopping the eyes from working together as a pair for an extended period of time, diagnostic occlusion allows us to measure the maximum amount that the eyes drifts. It also allows us to fully assess the underlying cause of the squint.

We will use this information to make decisions about how best to treat the squint. If your child is having surgery, these measurements will be used by your ophthalmologist to decide on the type and amount of surgery required.

What do you need to do?

  • Your orthoptist will give you an eye patch which you will need to keep safe until your next appointment.

Please put the patch on 1 eye hour(s) before your next appointment. Make sure that it is fully stuck down on the face and there are no holes to peep through.

  • It does not matter which eye is covered.
  • Do not remove the patch when you attend your appointment as normal – your orthoptist needs to see you with the patch in place, and will remove it in clinic for you.
  • If the patch is removed before the appointment or if your child tries to peep around the patch during the appointment, we will have to repeat the diagnostic occlusion. Your child will have to wear a patch for another period of time and another appointment may be required.

Contact us

If you have any questions, or if you lose your patch before your appointment, please contact us on 0114 271 7468.

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Please note: this is a generic information sheet relating to care at Sheffield Children’s NHS FT. These details may not reflect treatment at other hospitals. This information is not intended as a substitute for professional medical care. Always follow your healthcare professionals’ instructions. If this resource relates to medicines, please read it alongside the medicine manufacturer’s patient information leaflet. If this information has been translated into another language from English, efforts have been made to maintain accuracy, but there may still be some translation errors. If you are unsure about any of the guidance in this resource or have specific questions about how it relates to your child, always ask your healthcare professional for further advice.

Resource number: EYE45

Resource Type: Article

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