University of Edinburgh
 

Medical Information on Septo-optic Dysplasia

by Dr Andrew Blaikie for VI Scotland

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.

What this information is not for

This document is not a substitute for a consultation with a Health Professional. It should not be used as a means of diagnosing a condition.

We hope the information will help you to:

  • 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.

Medical Information on Septo-optic Dysplasia

What we see is made in the brain from signals given to it by the eyes. 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 focussing 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.

What is Septo-optic dysplasia?

The brain is split into two halves, a right and left half. A thin wall known as a septum separates these halves. Very rarely when a baby is growing in the womb not all of the parts of the eye and brain grow correctly. When a part of the body does not grow correctly it is known as dysplasia. In children with Septo-optic dysplasia parts of the brain in and around this septum and the optic nerves do not grow fully while in the womb. Poor growth of the optic nerves is usually called Optic Nerve Hypoplasia. Septo-optic dysplasia is often also called De Morsier Syndrome, after the doctor who first described the condition.

What is Optic Nerve Hypoplasia?

If a part of the eye does not grow to its full size this is known as hypoplasia. Hypo means less. Plasia means growth.

Optic nerve hypoplasia is a condition present from birth. In this condition the eye does not have all the usual wiring between the eye and brain. Less information about the visual world can then be given to the brain.

What is the cause of Septo-optic Dysplasia?

Nearly all cases of Septo-optic Dysplasia occur by chance. There is no good evidence that the condition runs in families or is caused by prescription or recreational drugs.

How does Optic Nerve Hypoplasia affect vision?

The loss of wiring can sometimes be only very small. The child will have near-normal vision. But sometimes it can be nearly all the wires with very little information being transferred. The child would then have poorer vision. Sometimes only the top or bottom part of the optic nerve is missing. When this happens then the opposite half of the visual world will be blurred, with the rest almost normal.

Sometimes children can develop fast to-and-fro movements of the eyes. This is called Nystagmus. Squint can also develop. Please ask us if you would like VI Scotland information documents on these conditions as well.

How is Optic Nerve Hypoplasia diagnosed?

Optic Nerve Hypoplasia can be diagnosed by looking into the eye with a special instrument. All the wires of the optic nerve can be seen 'end on' as they exit the eye and pass to the brain. This is the 'head' of the optic nerve.

If all the wires are present the 'head' of the optic nerve will look a normal size. If many wires are missing then the optic nerve may look smaller than usual. This is the common appearance in children with optic nerve hypoplasia.

A part of the brain that makes hormones is found near the septum

Often in children with Septo-optic Dysplasia a part of the brain that makes hormones does not work correctly. Parts of the body that make hormones are called glands. The pituitary gland is found near the septum. It is this gland that often does not develop and function correctly in children with Septo-optic dysplasia. The pituitary gland makes hormones that help children grow.

How can pituitary gland problems be diagnosed and what can be done to help?

If a child is born with optic nerve hypoplasia regular checks should be done. The checks are to make sure your child is increasing in height and gaining weight normally. Scans of the head may also help. They may show the pituitary gland to be either smaller than usual or absent altogether. Blood tests may also show that hormone levels are low. If this is the case hormone tablets need to be taken to help your child grow. A specialist children's doctor called a paediatric endocrinologist will monitor this treatment.

How can doctors help?

If one eye is affected more than the other, eye patching can help improve vision. Patching the child's better eye can encourage the poorer eye to develop improved vision. Sometimes children with optic nerve hypoplasia need spectacles. This can improve the child's vision. If children show signs of a lack of certain hormones, supplements can be taken.

How can parents, family, friends and teachers make a difference?

Many things can be done to help children with Septo-optic Dysplasia see better. We use our vision to get around, learn new things and to meet other people and make friends.

Most children with Septo-optic Dysplasia give the impression that their vision is normal. It is important however to consider what your child's particular problems with vision might be.

If your child has been prescribed spectacles, contact lenses or a Low Visual Aid (LVA) it is important that they are encouraged to wear and use them. This will help your child see more clearly and ensure the vision parts of the brain grow and develop correctly.

Problems at school may be due to some of the reading books being hard to see. This often means it takes longer and more effort to do the work. If the size of print is increased and letters and words spaced more widely most children will find schoolwork easier. Good bright lighting and crisp black print on a clean white background will also make things easier. Sometimes placing reading books on a slope, which tilts the print towards the child, will improve reading speed as well.

A child with Nystagmus who chooses to use a head turn or to move the head to and fro to improve vision should not be made to stop doing this. They are trying to improve their vision and are often doing it without knowing it.

It is also worth watching carefully to find out what the smallest toys are that a child can see and play with. Then try to only play with toys that are the same size or bigger. If your child has a part of the visual world missing it is important to know where this is. Then try to always place toys in the part of vision that is working. Placing one toy on a plain background will often help children see it more readily. Placing lots of toys of different size and colour close together on a patterned background can make them 'invisible' to some children.

Recognising facial expressions can often be difficult. It is worth trying to find out at what distance facial expressions can be seen and responded to. Then always try to talk and smile from within this distance. This helps a child to learn what facial expressions mean and to copy them.

Infants and young children need to learn about the world around them. Home visiting teachers, physiotherapists and occupational and speech therapists may all add to the child's care and education. It is important to continue the programmes that they recommend. If the child is involved in family activities vision can improve and new skills can develop.

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.

Who wrote these documents?

These pages are the consensus of opinion of many different people. They 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 worked as an Ophthalmology Research Fellow with Visual Impairment Scotland and is a member of the Royal College of Ophthalmologists.

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