ANOPHTHALMOS & RELATED CONDITIONS

• Overview Of Paediatric Ophthalmology
• Specific Eye Conditions

| ANOPHTHALMOS & RELATED CONDITIONS

Acknowledgements: The information on this page is based on that of MACS (microphthalmos and anophthalmos society UK) webpage. The information is designed for the assistance of parents and others who are assisting anophthalmic children.
The MACS webpage offers further support and discussion facilities to these people and it is recommended that their site is visited. Click here to visit MACS (UK) Home Page
This society's webpage is an excellent one with appropriate information, advice and support for parents and relatives of anophthalmic children
Anophthalmia
Anophthalmia (anophthalmos) is a condition that means one or both eyes didn’t form during the early stages of pregnancy.
There are three groups of patients with this condition.
1. Primary anophthalmia is a complete absence of eye tissue due to a failure of the part of the brain that forms the eye.
2. Secondary anophthalmia occurs when the eye starts to develop and for some reason stops, leaving the infant with only residual eye tissue or extremely tiny eyes which can only be seen under close examination.
3. Degenerative anophthalmia the eye started to form and, for some reason, degenerated. One reason for this occurring could be a lack of blood supply to the eye.
Causes
Incidence: True anophthalmia occurs in around 1 in 100,000 births.
Microphthalmia and coloboma occur in around 1 in 10,000 births.
Aetiology: Genetic- 2/3.
Environmental factors- 1/3 (drugs, pesticides, radiation, toxins or viral causes).
Viruses that have been linked to these conditions are toxoplasmosis, rubella and certain strains of the flu virus.
Research into the cause or causes of these distressing conditions has intensified over the past few years. One day the cause will be identified and hopefully lead to a significant reduction in the amount of children being born with these conditions.

Microphthalmia
Microphthalmia (microphthalmos) is a condition in which the eye(s) started to form during pregnancy but for some reason stopped, leaving the infant with small eyes. The size of the eye can vary from child to child.
If very mild it can almost go unnoticed while very advanced cases or extreme microphthalmia are really the same as some forms of anophthalmia.
Distinguishing between extreme microphthalmia and anophthalmia in such a case can be achieved only by examining especially stained tissue under a microscope but such a diagnosis is not usually of much practical importance.

Coloboma
Coloboma (colobomas or colobomata).
The word "coloboma" comes from the Greek word that literally translates to "mutilation". In this condition there has been a failure of the closure of the optic fissure leaving a gap in some or all of the structures of the eye. This condition is usually (but not always) apparent because the pupil is mis-shaped. It can often be a ‘cats eye’ or ‘keyhole’ shape. Again, this condition can occur in varying degrees.
Complete coloboma- all of the structures of the eye are involved; these are the choroid, the retina, the optic disc, the ciliary body, the macular and the iris. Lens colobomas can also occur but it is very rare and the cause isn’t very well understood.

Related Conditions
Some other conditions associated with coloboma, anophthalmia and microphthalmia are:
Congenital cataracts, optic disk abnormalities, congenital cystic eye, microcornea and persistent hyperplastic primary vitreous.
Nanophthalmia. Although similar sounding to anophthalmia, it means that the eye looks normal in appearance but the eyeball is significantly shorter. This condition appears to be hereditary.

Treatment
There is no cure for these conditions.
Sometimes the child may have other conditions or complications that may require monitoring.
Prosthetic eyes can be fitted to the empty eye sockets. This may involve surgery to the socket to make it easier to fit the prostheses but also to promote the growth of the eye socket. Conformers, similar to balloons that can be expanded inside the socket, are sometimes used to further encourage the growth of the socket.
Prosthetics
Prosthetic eyes are usually made from acrylic. Sometimes porcelain is used if there’s an allergy to the acrylic. If there is any vision at all in an eye then a prosthesis will not normally be fitted until the child reaches 5 years old. This is because if that eye is covered up for long periods the brain will cease to recognise the signals, causing a ‘lazy eye’. It is also important to establish if there is any useful vision in the affected eye(s), which is most reliably done at a later age.
After the age of 5-7 years then the brain is able to compensate and no vision will be lost. As the child grows the prosthesis will need to be checked regularly for size, comfort and fit (usually 2–3 times a year). It also needs to be polished and checked for any damage such as sharp edges etc.

Please remember that each child is different and this information should not be used to make a diagnosis. Any diagnosis should be made by a qualified ophthalmologist.