Visually Impairing Conditions
For whom is this information intended?
The information contained in this document is intended for use primarily by parents, other members of the family and older children with visual impairment. The information will also be of use to interested health professionals, carers and teachers.
The purpose of each information document
The purpose of the information is to explain:
- The way the eyes and brain normally work to make 'vision'
- The reason why vision may become impaired by a specific condition
- The cause of the condition
- How the condition is diagnosed
- The effects of the condition on the child's vision
- What can be done to help?
This document is written with the minimum use of medical terms and jargon. It is impossible to avoid all medical terms but where we have used them we have attempted to explain them as clearly as we can. Although the information is intended to describe most aspects of the condition each child is different and there will always be exceptions to the rule. As far as we can determine these pages are true and accurate and have been written in good faith. Inevitably there will be some mistakes. We apologise for this.
What this information is not for
This document is not a substitute for a consultation with a Health Professional and should not to be used as a means of diagnosing a condition. It is not a means to access a 'second opinion' particularly in any medico-legal cases. We hope the information will help you.
After reading the information we hope you will:
- Have a better understanding of the condition
- Know what tests and treatments are normally available
- Know when to seek professional advice
- Be able to discuss the condition in a more informed way
- Make the most of consultations with carers, teachers and health professionals
- Be reassured and more able to cope
Due to staffing limitations we are not able to offer telephone or email advice to parents of children who are not notified with VI Scotland.
These pages represent the consensus of opinion of many different people who include Parents of Visually Impaired Children, Visually Impaired Children themselves, Community Paediatricians, Ophthalmologists, Educationalists and Psychologists. The main author and person responsible for their content is Dr Andrew Blaikie who is an Ophthalmology Research Fellow with Visual Impairment Scotland and a member of the Royal College of Ophthalmologists.
We are very keen that parents and children feedback to VI Scotland about
these information documents.
Visual Impairment, Scotland Scottish Sensory Centre, The University of Edinburgh, Holyrood Road, Edinburgh EH8 8AQ
Telephone Number: 0131 651 6078
Fax Number: 0131 651 6502
Textphone: 0131 651 6067
What we see is made in the brain from signals given to it by
What we see is in fact made in the brain. The brain makes sight from signals given to it by the eyes.
What is the normal structure of the eye?
The eye is made of three parts.
- A light focusing bit at the front (cornea and lens).
- A light sensitive film at the back of the eye (retina).
- A large collection of communication wires to the brain (optic nerve).
A curved window called the cornea first focuses the light. The light then passes through a hole called the pupil. A circle of muscle called the iris surrounds the pupil. The iris is the coloured part of the eye. The light is then focused onto the back of the eye by a lens. Tiny light sensitive patches (photoreceptors) cover the back of the eye. These photoreceptors collect information about the visual world. The covering of photoreceptors at the back of the eye forms a thin film known as the retina. Each photoreceptor sends its signals down very fine wires to the brain. The wires joining each eye to the brain are called the optic nerves. The information then travels to many different special ‘vision’ parts of the brain. All parts of the brain and eye need to be present and working for us to see normally.
Very rarely when a baby is growing in the womb an eye (ophthalmia) may
not grow to its full size. It may instead be smaller (micro) than it should
be. This is known as Microphthalmia. Very rarely an eye may not grow at
all. This is known as Anophthalmia. Usually both eyes are affected.
Most cases of Anophthalmia occur by chance.
There is no good evidence that Anophthalmia is caused by prescription, recreational drugs or chemicals.
If both eyes have almost completely failed to grow properly then the child will have severely reduced vision. The child may only see bright lights and large shapes. Some children will be blind and not even see bright light.
Are their any conditions associated with Anophthalmia?
If only one eye appears to be affected it is important to have the other eye examined. Sometimes the other eye is slightly smaller than normal. This can lead to problems with:
- Raised pressure in the eye (glaucoma)
- A cloudy lens (cataract)
- Poor vision because the retina is not working properly
See the VI Scotland information on Glaucoma and Cataract. Occasionally when the baby is in the womb parts of the face and mouth do not grow correctly. The most common problem is cleft palate where the nose or lips do not form properly.
Learning difficulties can sometimes also occur along with Anophthalmia.
What is the chance of the same parents having another
child with Anophthalmia?
There is an increased chance of the same parents having another child with Anophthalmia. Experts suggest that on average there is about a 1 in 8 chance. This can be as high as 1 in 4, especially if the parents are originally from a certain part of the world, such as the Middle East.
Very rarely even though there does not appear to be an eye present small parts of the eye can still have grown. The small parts of the eye that are present even if they are under the skin can help the child see bright lights and shapes. Special tests and careful observation of the child’s behaviour can help tell if some vision is present.
Growth abnormalities of the face and lip such as cleft palate can be corrected surgically.
Prosthetic (artificial) implants can be placed in the bony orbital cavity. This can help the face grow normally and symmetrically.
If other problems develop in the other eye, such as cataract or glaucoma, an ophthalmologist can usually offer treatment to help.
It is important that the parents seek genetic counselling.
How can parents, family, friends and teachers make a difference?
Children with Anophthalmia and poor vision need early and specialist care from the local visual impairment support team.
Even if a child has very poor vision many useful and practical things can be done to improve the ability of the child to get around, interact with other children and learn.