[Deformation of the central corneal surface following use of hard and soft contact lenses].

Use of a computer connected with a slit-lamp-video-camera detected changes in the cornea topography after wearing contact lenses on a daily basis. Also subtle surface changes were observed within the upper portion of the areas measured. These appeared to be spiral-shaped or cloudlike patterns as a result of wearing hard or soft contact lenses respectively. The changes observed appeared to have resulted from movement of the contact lens. However, this device has also been used to determine changes that are similar in early keratokonus. The computer can store data from 1600 sites on the surface; there sites are distributed over a 4-mm diameter area in the central cornea. On command the computer can display an image of the corneal surface. Images from hour 0 and 6 weeks later were compared to determine the topographic differences. The surface patterns observed after 6 weeks of wearing lenses appeared to be involve numerous small depressions.