bilateral means both sided. bilateral keratoconus therefore means that both eyes are involved. Keratoconus is an asymmetric bilateral disease. Keratoconus means coning of the cornea. The clear front part of the eye is cornea. When internal pressure of the eye is able to overcome the resistance of the cornea, it leads to bulging of the cornea. This is termed as keratoConus. Usually one eye may be more involved. To the untrained eye this may be unilateral. But to Los Angeles keratoconus expert the second eye may still have subtle signs of keratoconus/