(also cyclocephaly or synophthalmia) is a rare form of holoprosencephaly and is a congenital disorder (birth defect) characterized by the failure of the embryonic prosencephalon to properly divide the orbits of the eye into two cavities. Its incidence is 1 in 16,000 in born animals, and 1 in 250 in embryos, one in 2,500 that end in miscarriage.
Typically, the nose is either missing or replaced with a non-functioning nose in the form of a proboscis. Such a proboscis generally appears above the central eye, or on the back, and is characteristic of a form of cyclopia called rhinencephaly or rhinocephaly. Most such embryos are either naturally aborted or are stillborn upon delivery.
Although cyclopia is rare, several cyclopic human babies are preserved in medical museums (e.g. The Vrolik Museum, Amsterdam).
Some extreme cases of cyclopia have been documented in farm animals (horses, sheep, pigs, and sometimes chickens). In such cases, the nose and mouth fail to form, or the nose grows from the roof of the mouth obstructing airflow, resulting in suffocation shortly after birth.
A British description from 1665 of a colt apparently suffering from cyclopia reads:
First, That it had no sign of any Nose in the usual place, nor had it any, in any other place of the Head, unless the double Bagg CC that grew out of the midst of the forehead, were some rudiment of it. Next, That the two Eyes were united into one Double Eye which was placed just in the middle of the Brow.
On 1 March 1793 a 46-year-old woman in Boalts Torp, Glimåkra, Sweden gave birth to a child with cyclopia that died after 2 hours. The child was 35 cm long, its face without nose and nostrils, the lidless eye with no eyebrow sat raised on the middle of the forehead like a large blueberry. The wrists were somewhat crooked as well as the right foot which was completely crooked and bent inwards. It was not clear whether it was a boy or a girl but it was believed to be the former.
A Swedish description from 1793 of a newborn with cyclopia
On December 28, 2005, a kitten with cyclopia, “Cy”, was born in Redmond, Oregon, United States and died about one day after birth.
In 2006, a baby girl in India with cyclopia was born. Her only eye was in the center of her forehead. She did not have a nose and her brain was fused into a single hemisphere. The child died 1 day after her birth.
In 2011 a cyclops shark fetus was discovered in the body of a caught shark in Mexico, with no discernible nose and one giant eye. The unborn fetus was turned over for medical studies.
In 2012 (October 10), a small kitten was born. Its eye was in the center of the forehead and there was no developed nose to be found. The small cat died shortly after it was born. It was nicknamed Cleyed the Cyclops.