[Keratoconus and familial topographic corneal anomalies]

Computer-assisted corneal topography, allows the detection of early abnormalities, including abortive or subclinical forms of keratoconus. So, it is possible to identify affected individuals with variable degrees, in family members of patients with keratoconus, to draw pedigrees, and to specify the mode of inheritance.

Computer-assisted digital videophotokeratoscope was used to map the corneas of 106 family members of 30 patients with keratoconus.

Abnormalities observed included the inferior cornea markedly steeper than the superior cornea (I-S - 0.86 +/- 0.44 D) and a marked difference between the central corneal powers of the two eyes (delta PC = 0.72 +/- 0.22 D). However, there was no statistical difference with normal individuals for central corneal power.

Pedigree analysis in these families suggests, in 50% of them, an autosomal dominant mode of inheritance. However, it is impossible to conclude for the other families, because of an insufficient number of cases.