Cornea Plana Congenita is a rare hereditary corneal defect.



(1) autosomal dominant: CNA1

(2) autosomal recessive: CNA2


Chromosome: 12q21

Gene: KERA

Gene product: keratocan (a leucine-rich proteoglycan)


Clinical features:

(1) reduced corneal curvature, usually bilateral

(2) indistinct border at the corneal limbus

(3) arcus lipoides occurring at an early age

(4) poor visual acuity if uncorrected, often with ametropic amblyopia


The recessive form has a centrally-located round and opaque corneal thickening. This is absent in the dominant form.


A patient with congenita plana may have:

(1) sclerocornea

(2) malformations of the iris

(3) slit-like pupil

(4) adhesions between the iris and cornea (Peters' anomaly)


A properly fit contact lens often can provide a good visual and cosmetic outcome.


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