Corneal changes in X-linked ichthyosis.

X-linked ichthyosis (XLI) is an inherited dermatological disorder which is characterized by dryness of the skin and thick scaling of the trunk and extremities. Nearly all cases demonstrate a specific corneal dystrophy which appears as a thin, gray-white, "frosted" layer deep in the stroma. Since other forms of ichthyosis present with similar cutaneous features causing confusion in the dermatological assessment, optometric identification of corneal changes in suspected individuals allows for definitive diagnosis. In addition, most female carriers of XLI present with corneal opacities of the same nature, although these are generally less prominent. Early detection of these corneal variations in mildly symptomatic females, and especially in sisters of affected males, can be the initial step toward identification of carriers of the trait.