Sightlines : Cornea, Cornea

It’s not an infrared picture of the earth, or the next storm moving this way. You are looking at a color-coded topographic map of a cornea, the clear, convex membrane that covers the iris (source of Frank’s ol’ blue eyes). The image was created by a computer-assisted corneal mapping system, a high-tech successor to the standard keratometer used to detect inconsistencies in the shape of the cornea that cause vision problem.

A scan of a normal cornea is blue around the edges and green in the center (reds and yellows represent bulges; the blues and greens, flatness). The cornea mapped on the left protudes conspicuously near the pupil, a sign of astigmatism CK. Corneal mapping allows this information to be fed directly into a computer, which spits out specifications used to make perfectly fitted contact lenses on the spot. Developed a decade ago, computer corneal mapping was first used clinically by eye surgeons. Now, despite requiring hardware and software that cost about $25,000, the imaging is increasingly popular with optometrists and patients. California, ever the leader in embracing high techery. sports 43 corneal mapping systems in optometry offices alone.