Anophthalmia and Microphthalmia

 

Condition Description

Anophthalmia (AN-off-THAL-mee-ah) is a general term that means one or both eyes have not formed during early fetal life. There are several variations of this condition. Primary anophthalmia is the complete absence of the globe of the eye (the “eyeball”), although the eyelid, conjunctiva and lacrimal structures are present. It may or may not be associated with malformations in the brain. Secondary anophthalmia is a term for very tiny eyes or just a small amount of eye tissue because the process of development of the eye stops during fetal life, for an unknown reason. A third category is called degenerative anophthalmia, where the eye started to form but the blood vessels supplying the developing eye were damaged and the development was not complete.

Microphthalmia(my-krof-THAL-mee-ah) is an eye condition where the globe size is at least two standard deviations below the average size for a child of a comparable age. Microphthalmia can be either simple or complex. Simple microphthalmia refers to an intact eye with shortened total length of the globe; complex microphthalmia refers to malformation of various parts of the eye in addition to its small size. These eye conditions are caused by chromosomal abnormalities or prenatal exposure to rubella, toxoplasmosis, alcohol, thalidomide, hydantoin, or LSD that damage the developing eye before birth.

Prevalence

These are very rare conditions, occurring in 1 of 10,000 live births. They account for 3-11% of blindness in children. About 2/3 of these conditions are considered to be genetic.

Common Associated Conditions

There may be brain abnormalities in addition to the eye condition, and sometimes syndromes will involve small eye size or absence of the globe.

Short-term Treatment and Outcomes

There is no cure for these conditions, but many treatments are available to the child and family. A computerized tomogram (CT) or magnetic resonance imaging (MRI) will be needed to determine the extent of defect. The optic nerve and extraocular muscles will need to be carefully examined. A genetic workup would be advised with family counseling as indicated. No treatment is needed for mild or moderate microphthalmia. Prosthetics will be used in anophthalmia as well as surgery to expand the palpebral fissures (opening of the eye between the upper and lower lids) and orbit (boney eye socket). Reconstructive surgery is typically performed a bit later in childhood to allow growth of the facial bones, although there may be some preliminary surgeries done earlier. It will be important to have regular visits to eye specialists who will fit conformers (eye prostheses) that are increased in size as the child grows. Children may be very sensitive to light (called photophobia) and tinted glasses might be very helpful to them. Their vision may be enhanced with corrective lenses, in some cases.

Long-term Treatment and Outcomes

If there is any vision in the eye, a prosthesis will not be fitted until at least 5 years old so that the brain will receive signals through the eye and thus the optic nerve and brain structures for vision will receive input. If this does not occur in the first 5 years of life the optic nerve atrophies. Orbital implants will need to be monitored and further surgery to reconstruct the orbit and eyelids may be required as the child grows. New prosthetic devices and surgeries can have good cosmetic results. If a child has an unaffected eye, vision in that eye must be protected.

Common Complications

Further vision loss or damage to an unaffected eye are ongoing concerns. Children with eye defects are always at increased risk for detached retina (injury to the delicate tissue at the back of the eye) or glaucoma (increasing pressure in the eye that can damage the optic nerve).

Implications for Children's Development

Early intervention in special programs for children with blindness or low vision is essential to assist the child to increase sensory input as they develop. Motor development can be on a somewhat different timeline for infants and young children with visual deficits since they may need adaptations and assistance to explore their environment safely.

Children with blindness or partial sight may have learning difficulties or behavioral concerns. This is because other parts of the brain form at the same time as the eyes. A great deal of special help is available through the school system to children and families with vision difficulties, and many occupational therapists have special training to assist them. Parent-to-parent support and advocacy groups might be very helpful. There are many online resources for sharing information between centers and families.

A strength-based approach is very important. The child's many abilities are emphasized and the congenital conditions are de-emphasized to build independence and self-confidence. Social development is just as important as the physical and mental aspects. Mainstreaming the child into social groups and classrooms with age-mates will help the child develop friendships, a positive self-concept, and learn to take risks appropriately. Therapeutic nursery schools, social clubs, and summer camp experiences can be very helpful to children and families. The child and family should be exposed to people who live full and active lives despite their vision problems.

Career choices have greatly expanded for individuals with visual concerns due to the many technical adaptations that are now possible (i.e. voice-recognition software, etc.) The Americans with Disabilities laws and regulations have mandated services and access for individuals with all sorts of issues and higher education is very much an option.

For more information, including resources for parents and general information about congenital eye conditions, visit the following websites: