Glasses and testing for glasses (Hospital Refraction)
Information for patients from the Orthoptics Department
Your orthoptist has decided that your child needs to be tested for glasses. We hope this leaflet answers some of the questions you may have. If you have any further questions or concerns, please speak to your orthoptist.
Why do people need glasses?
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Glasses are needed when light rays do not come to a common focus on the retina (back of the eye). For example, the image of the object is not sharply defined.
The ability to see starts when light rays pass through the eye. Rays pass the cornea (the clear surface on the front of the eye) and the lens inside the eye. The lens helps bend and focus the light rays.
Any irregularities in corneal or eye shape results in a visual defect. This is known as a refractive error, and includes hypermetropia, myopia, and astigmatism.
What are hypermetropia, myopia, and astigmatism?
Hypermetropia is also known as long-sightedness. It means that you are more likely to see better at long distance than short distance. Some children have hypermetropia and need glasses. These children often struggle to see things at long and short distance.
Myopia is also known as short-sightedness. It means that you are more likely to see better at short distance than long distance.
Astigmatism is the term given to an eye that has an irregular curvature of the cornea. Rather than the uniform curving (like a football), the eye is more curved in one direction than the other (like a rugby ball). Light rays passing through the eye will not have a common focus. This will cause blurred vision at all distances.
Who will arrange my child's refraction appointment?
A refraction appointment is generally arranged by the orthoptist as a routine assessment.
What will happen when we arrive for my child’s appointment?
Please report to the Outpatient reception. They will direct you to the Eye Department.
All children will have seen the orthoptist at a previous appointment or on the same day, for their usual orthoptic tests.
You will stay with your child for each part of their assessment.
What will happen at my child's refraction appointment?
An orthoptist or optometrist will dilate (enlarge) your child's pupil with Cyclopentolate drops. The drops will also relax your child's focussing. This will enable the optometrist or ophthalmologist to:
gain an accurate test for glasses; and
assess your child's eye health.
The drops will take at least 30 minutes to work. During this time, you can have something to eat or drink, or your child can play in the waiting area.
If your child has dark eyes, we may need to instill two sets of drops.
When your child’s pupil is enlarged, the optometrist or ophthalmologist will have a clear view of the back of your child’s eye. By moving a line of light across their retina, they will be able to judge what strength of glasses your child needs.
If your child needs glasses, we will give you a prescription to take to your local optician. They will make up the glasses for you. For more information, please read the How to get your child’s glasses leaflet.
The drops take at least 30 minutes to take effect. Allow at least 1 hour for your whole appointment.
Will the drops hurt?
The drops may sting slightly when they are first put in. This is normal and nothing to worry about.
On a bright day, a peaked hat or sunglasses may make your child more comfortable after their test. Dilated pupils are more sensitive to light.
Will my child need a follow-up appointment?
Yes. The hospital will arrange a follow-up orthoptic appointment. At this appointment we can check your child’s vision with their new glasses.
How long will my child’s eyes be affected by the drops?
Your child’s vision will be blurred for up to 6 hours after dilation.
Your child’s pupils will be enlarged for 24 to 48 hours.
This is normal and nothing to worry about.
Will my child “grow out” of their glasses?
This depends on:
the general changes with growth of your child’s eye shape and size; and
what prescription strength your child needs.
Each case is different. Most will need glasses throughout childhood, whilst their visual system is maturing, and into their adult years. Contact lenses may be an alternative to glasses in adulthood.
Some children may “grow out” of the need for glasses. We will discuss this with you at your child's regular check-ups.
What happens if my child does not wear the glasses?
We encourage your child to wear the glasses full time, and allow your child to “settle into” the glasses. Most children with a visual weakness will happily wear their glasses. However, some of those who manage to compensate for the weakness may need more time to “settle into” theirs. In the worst-case scenarios, we may prescribe drops to encourage this. You can discuss this with your child's orthoptist.
What are the benefits of glasses?
If found and corrected early enough, your child will be able to see well and their eyesight will develop normally.
Any residual weakness in your child’s eyesight may be treated more effectively. For example, they may receive occlusion (patching) treatment.
Your child will avoid eye strain.
Are there any risks?
If your child has a significant refractive error that is not corrected at an early enough age, there is the risk:
that their eyesight will not develop normally; and
they will never be able to see well.
This may mean they cannot drive. A child’s eyesight is still in its developmental stages up to around 8 years of age.
Problems with eyesight may also affect your child’s ability to concentrate. It may affect learning and schoolwork.
As with all medication, there may be side effects with the eye drops. Although rare, they may cause a slight rise in body temperature and general irritability.
What if I have any questions or concerns?
We hope that this leaflet has answered your questions. However, if you still have concerns that you would like to discuss with your orthoptist, please telephone 01227 868615.
Further information
[Web site last accessed 13 March 2026]
Glossary
An ophthalmologist is a doctor who specialises in the diagnosis and treatment of eye diseases.
An orthoptist is a person who specialises in the detection and management of eye movement disorders.
An optometrist is a person who specialises in investigating the need for glasses. They check the health of the eyes and visual system.
An optician is a person who dispenses glasses.
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