Thanks to the gracious contribution from MACS (our sister support group in the United Kingdom), I now have a comprehensive definition leaflet about Anophthalmia, Microphthalmia, and Coloboma for you.

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Anophthalmia (anophthalmos) is a condition that means one or both eyes didn’t form during the early stages of pregnancy. There are three classifications for this condition.

Primary anophthalmia is a complete absence of eye tissue due to a failure of the part of the brain that forms the eye.

In secondary anophthalmia 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.

In 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.


There is no cure for this condition. Sometimes the child may have other conditions or complications that may require monitoring. Prosthetic eyes can be fitted to the empty eye sockets which can sometimes involve surgery for reasons such as putting implants into the socket to make it easier to fit the prostheses. Prostheses are not just for cosmetic purposes but also help to promote the growth of the eye socket. Conformers, which are a bit like balloons that can be expanded inside the socket, are sometimes used to further encourage the growth of the socket.

Microphthalmia (microphthalmos) is a condition that means 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 but is usually

very obvious. At the other end of the scale there is extreme microphthalmia which is really the same as some forms of anophthalmia. Distinguishing between extreme microphthalmia and anophthalmia in such a case can be achieved by examining especially stained tissue under a microscope but such a diagnosis isn’t usually of much practical importance.

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 (see diagram on reverse of this leaflet). Again, this condition can occur in different severities.

Complete coloboma is when all of the structures of the eye are involved; these are the choroid, the retina, the optic disk, 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.

Some other conditions associated with coloboma, anophthalmia and microphthalmia are:

Congenital cataracts, optic disk abnormalities, congenital cystic eye, microcornea and persistent hyperplastic primary vitreous. There is also 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.


There is no cure for microphthalmia or coloboma. These conditions should be monitored according to the complexity of the eye involvement. There is a small increased risk of detached retina or glaucoma. Hospital visits will probably be more frequent during the early years but will depend on the individual needs. The patient may be discharged when the condition is seen to be stable and there are no other complications. If the eye is small or badly malformed then artificial eyes or lenses (sometimes called scleral shells or prostheses) can be fitted for cosmetic and/or for promoting socket growth. Children with coloboma often have a dislike to strong light (photophobia) because the pupil can’t react to light in the normal way. Tinted glasses might be recommended.


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.



All of these conditions can result in the child being blind or partially sighted. Children who have a visual impairment that is due to a congenital condition sometimes have other problems such as learning difficulties or behaviour problems. Occasionally there are more severe problems or disorders. This is because the brain forms at the same time as the eyes, which are really an extension of the brain rather than separate organs.


True anophthalmia occurs in around 1 in 100,000 births. Microphthalmia and coloboma occur in around 1 in 10,000 births. Around 2 thirds of these cases are believed to be genetic. The remaining are thought to be caused by environmental factors such as drugs, pesticides, radiation, toxins or viral causes. Some viruses that have been linked to these conditions are toxiplasmosis, 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.

The information contained on this page is intended for use as a guide for anophthalmia, microphthalmia and coloboma. We hope that you find its contents useful and informative. All of this information has been put together by parents of children born with these conditions and has been gathered from various professional sources. As far as we can determine, its contents are true and accurate. 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.


We gratefully acknowledge Dr Danny Morrison, ophthalmologist, for his assistance in putting this information together.


Published and produced by:

The Micro & Anophthalmic Childrens Society

1 Skyrmans Fee

Frinton On Sea


United Kingdom

CO13 0RN

Telephone or Fax 01255 677511


Patron: Anne Diamond


Visit our web site at:

Registered Charity Number 1040074


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