What is Anophthalmos?
Anophthalmos is a medical condition defined as the complete absence of an eye from its eye socket. Anophthalmos is congenital and happens during fetal development. It occurs when the primary optical vesicle fails to develop properly. The lack of an eyeball causes poor development of the eye socket (orbit), so the eyelids appear shrunken and displaced backwards. Anophthalmos can occur as an isolated condition or may be associated with other medical conditions such as craniofacial or limb defects. The treatment for anophthalmos is orbital expansion. The eye socket is made larger and an ocular prosthesis (artificial eye) is put into the eye socket. Anophthalmia results in blindness or very limited vision.
Key Takeaways
- Anophthalmos is defined as a complete absence of the eyeball from the eye socket.
- Anophthalmos is a developmental issue that happens in the womb. It can be caused by genetic mutations or by infections during pregnancy.
- People with anophthalmos (no eyeball) have no or poor vision, but ocular prosthetics can be used to help with the cosmetic appearance.
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Understanding Anophthalmos
Anophthalmos happens when the optic vesicle does not develop properly when the baby is in the womb. The optic vesicle forms around the fifth week of gestation. The optic vesicle eventually forms the retina, optic nerve, and hyaloid artery that deliver nutrients and light signals to the eye. It is very important for the optic vesicle to grow properly in order for the eye’s structures and functions to be intact at birth. Anophthalmos and failed development of the optic vesicle is associated with several genetic mutations. Intrauterine infections can also cause anophthalmos.
Intrauterine infections that may cause anophthalmos include the TORCH infections:
- Toxoplasmosis
- Other (Syphilis, HIV, Varicella Zoster)
- Rubella
- Cytomegalovirus
- Herpes Simplex Virus
What Are The Symptoms Of Anophthalmos?
The main sign of anophthalmos is the absence of one or both eyes. The eye with anopthalmos will be blind because none of the optic structures that interpret light, such as the optic nerve or retina, are present. Other systemic abnormalities may also be present, depending on the underlying cause. For example, if anophthalmos is caused by a rubella infection during pregnancy, it may also cause deafness, heart disorders, and cognitive deficits. Women who are planning to get pregnant should check with their doctor to make sure they are vaccinated against infectious diseases prior to pregnancy, to prevent anophthalmos.
How Is Anophthalmos Diagnosed?
Anophthalmos is very rare. It only occurs in 0.18 per 10,000 births. Microphthalmos is often confused with anophthalmos. Microphthalmos is defined as a very small eyeball with reduced volume. Both conditions, microphthalmia and anophthalmia, look like the eyeball is missing. However, microphthalmos does have a small amount of eye tissues present that is only visible with ultrasound technology.
Prenatal ultrasonography can detect if the fetus has anophthalmia. If there is anophthalmia, the 3D prenatal ultrasound will show that the eyes and intraocular lens are missing. Anophthalmia can typically be detected by ultrasound at weeks 11 and 12 of gestation.
Anophthalmos is also diagnosed based on a physical examination at birth. There will be no visible ocular structures upon physical examination of the eye. The eye with anophthalmia will have defects such as collapsed eyelids, narrow eye opening, and backward displaced eye socket (orbit) that causes a “sunken in” appearance of the eye.
Eye conditions associated with anophthalmos:
- Optic nerve hypoplasia:
an under-developed or absent optic nerve. The optic nerve connects the eye to the brain. - Coloboma:
missing pieces of tissue in one or more eye structures. - Aniridia:
A congenital absence of the iris (colored part of the eye). - Cataract:
A clouding of the intraocular lens. - Glaucoma:
Damage to the optic nerve.
What Are The Treatments For Anophthalmos?
The treatment for anophthalmos is non-surgical orbital expansion. A socket expander, also known as a conformer, is placed into the eye socket when the infant is around three months old. With a conformer in place, the eye socket will get larger and closer to normal proportions. As the eye socket grows over time, larger conformers are put into the eye socket. An ocular prosthesis, a ‘fake eyeball’, can also be put over the conformer to improve the cosmetic appearance and mimic the appearance of an eye.
