Megalocornea
Horizontal diameter of cornea at birth is about 10 mm and the adult size of about 11.7 mm is attained by the age of 2 years. Megalocornea is labelled when the horizontal diameter of cornea is of adult size at birth or 13 mm or greater after the age of 2 years. The cornea is usually clear with normal thickness and vision. The condition is not progressive. Systemic association include Marfan's, Apert, Ehlers Danlos and Down syndromes.
Differential diagnosis
1. Buphthalmos. In this condition IOP is raised and the eyeball is enlarged as a whole. The enlarged cornea is usually associated with
central or peripheral clouding and Descemet's tears (Haab's striae).
2. Keratoglobus. In this condition, there is thinning and excessive protrusion of cornea, which seems enlarged; but its diameter is usually normal.
Microcornea
In microcornea, the horizontal diameter is less than 10 mm since birth. The condition may occur as an isolated anomaly (rarely) or in association with
nanophthalmos (normal small eyeball) or microphthalmos (abnormal small eyeball).
Cornea plana
This is a rare anomaly in which bilaterally cornea is comparatively flat since birth. It may be associated with microcornea. Cornea plana usually results in
marked astigmatic refractive error.
Congenital cloudy cornea
The acronym 'STUMPED' helps to remember the common conditions to be included in differential diagnosis of neonatal cloudy cornea. The conditions
are as follows:
Horizontal diameter of cornea at birth is about 10 mm and the adult size of about 11.7 mm is attained by the age of 2 years. Megalocornea is labelled when the horizontal diameter of cornea is of adult size at birth or 13 mm or greater after the age of 2 years. The cornea is usually clear with normal thickness and vision. The condition is not progressive. Systemic association include Marfan's, Apert, Ehlers Danlos and Down syndromes.
Differential diagnosis
1. Buphthalmos. In this condition IOP is raised and the eyeball is enlarged as a whole. The enlarged cornea is usually associated with
central or peripheral clouding and Descemet's tears (Haab's striae).
2. Keratoglobus. In this condition, there is thinning and excessive protrusion of cornea, which seems enlarged; but its diameter is usually normal.
Microcornea
In microcornea, the horizontal diameter is less than 10 mm since birth. The condition may occur as an isolated anomaly (rarely) or in association with
nanophthalmos (normal small eyeball) or microphthalmos (abnormal small eyeball).
This is a rare anomaly in which bilaterally cornea is comparatively flat since birth. It may be associated with microcornea. Cornea plana usually results in
marked astigmatic refractive error.
Congenital cloudy cornea
The acronym 'STUMPED' helps to remember the common conditions to be included in differential diagnosis of neonatal cloudy cornea. The conditions
are as follows:
- Sclerocornea
- Tears in Descemet's membrane
- Ulcer
- Metabolic conditions
- Posterior corneal defect
- Endothelial dystrophy
- Dermoid
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