The theory of corneal curvature change with the Intrastromal Corneal Ring

The Intrastromal Corneal Ring (ICR) is a new corneal implant designed to alter anterior corneal curvature. After insertion into the peripheral corneal stroma, the ring may be mechanically expanded or constricted. We constructed a mathematical model to assess the amount of corneal flattening or steepening that might result from ICR expansion or constriction, respectively. The model predicted increased corneal flattening with increasing expansion of the ICR circumference. Progressive corneal steepening with increasing constriction of ICR circumference was predicted. Incremental reductions in initial ring diameter sizes resulted in increased degrees of predicted corneal flattening or steepening. The mathematical model of the ICR function illustrates the potential of the ICR to correct myopia or hyperopia.