Medical Information

The Conditions

Anophthalmia (eyelessness) is the medical term used to describe the absence of the globe and ocular tissue from birth. Microphthalmia means an eye so small and poorly developed that it is barely visible. Coloboma is the name given to the condition when part of the eye does not develop.

These conditions can affect one or both eyes. In anophthalmia there is total blindness on the affected side. Microphthalmic eyes can have a very reduced level of vision which, when both eyes are affected, is very useful sight. With coloboma, the visual impairment is variable. When one eye is absent the other eye may be completely normal with good sight, or abnormally developed with poor vision. These are not new conditions, but both are very rare. Microphthalmia is ten times more common than anophthalmia but it is still a rare condition.

Associated problems

In addition to blindness or impaired vision, these children may have developmental and behavioral problems and other mental and physical disabilities.

These conditions may occur with other congenital anomalies of the face or body in up to one third of children. These anomalies may be relatively small or severe e.g. congenital heart disease, dyspraxia, brain damage, kyphosis of spine, deafness, abnormalities of colon and digestive system.

Causes

These conditions are the result of damage to the developing eye in the embryo in very early pregnancy (before 10 weeks). The causes in most cases are not well understood or easily identified, but are likely to be both genetic and environmental. It is very rarely inherited, but there is no specific genetic test. External causes include damage to the developing eye by certain medicines taken by the mother in early pregnancy. Environmental pesticides have been suggested as a cause, but there is no definite evidence of this.

 

The Medical Treatment

A report written by one of the Trust’s medical advisers, Mr Danny Morrison, stated that although the diagnosis is apparent on external examination, referral to an ophthalmologist (eye specialist) is essential for detailed examination of the eye or remnants of eye tissue. Because there may be other developmental problems, and
because up to one third of the children suffer from other physical or mental disabilities, all affected children should be examined by a paediatrician or clinical geneticist. A child born with anophthalmia or microphthalmia may need several blood tests (e.g., to examine chromosomes) and investigations such as photographs, head scans (ultrasound, CAT or MRI scans). These tests assist with both diagnosis and some of the treatment, e.g., when making artificial eyes.

The ocular orbits are very important in facial development and if the orbit globe is missing or too small the face will not grow properly. It is essential for children with anophthalmia or microphthalmia that remedial action is taken. Conformers, which are plastic structures made by the ocularist, help support the growth of the eye socket and the bones in the face. As the child grows and the orbits and facial bones develop, the ocularist, working closely with the ophthalmologist and oculoplastic surgeon, can make conformers and prosthetic eyes that are best for the child. Since each child is different, the age when he or she is ready for a prosthetic eye varies. In any case, during childhood several visits to hospital are necessary as the child’s growth develops.