Microcornea with myopia.

THE normal corneal horizontal diameter is 12 mm. and any value less than 11 mm. is considered to represent the condition of microcornea (Mann, 1958). The term should be applied only to eyes which are normal except for a small cornea. Corneal curvature is increased so that the corneal refraction is usually great, but associated myopia of varying degrees has been observed by Biro (1935), Puglisi-Duranti (1936), and Hohr Cast'an (1945). Biro (1935) reported a youth aged 18 years with high constantly-progressive myopia from early childhood, whose vision could be improved with -28 D sph. to only 5/30. The patient had large, prominent ectatic eye balls and flat microcorneae, measuring 10 mm. horizontally and 10l5 mm. vertically. There was no other abnormality excepting a radial groove of the iris without coloboma. Hohr Castan (1945) described a patient with myopia of -11 D sph. with myopic fundus changes. The right eye also had a large coloboma of the choroid and optic nerve. The diameter of the right cornea was 8 mm. and that of the left 10 mm. The radius of corneal curvature was 6-9 mm. in the right eye and 7-4 mm. in the left. We have encountered two cases of microcornea with myopia in brother and sister. Their mother shows a bilateral honeycomb type of central degeneration of the fundus, and the maternal grandfather and maternal aunt are said to be myopic (Fig. 1). The exact measurements for the two patients are given in the Table (overleaf).