Keratoconus
is a progressive eye disease
in which the normally round cornea
thins and begins to bulge into
a cone-like shape. The cornea
is the clear, central part of
the surface of the eye, which
is responsible for most of the
eyes focusing power. In patients
with keratoconus, the
cone-shaped cornea deflects light
and causes distorted vision.
Keratoconus often begins
to develop between the teen years
and the early 20s, although it
can develop at any age. Changes
in the shape of the cornea occur
gradually, usually over several
years. Patients with keratoconus
often experience blurred and distorted
vision, nearsightedness, and sensitivity
to light.