Diagnostic instrumentation advances benefit refractive surgeons, patients

January 1, 2008

Innovations in diagnostic technology have implications for improving the screening and follow-up of refractive surgery patients. An ophthalmologist reviews equipment and features that are newly available and others that are on the near horizon.

Key Points

Dr. Reinstein provided an update on some of the most recent advances in diagnostic instrumentation that are relevant to refractive surgeons, focusing on improved methods for measuring IOP after refractive surgery, instrumentation for measuring quality of vision, developments in corneal topography, and new indices for keratoconus screening. He is the medical director of the London Vision Clinic, London, and assistant professor of clinical ophthalmology, Weill Medical College, Cornell University, New York.

Measuring IOP

The CH-measuring instrument is a modified air-puff tonometer that provides an IOP measurement that is virtually independent of corneal thickness.

"While it does not directly measure pressure in the eye, [this instrument] does a very good job of approximating the value," Dr. Reinstein told Ophthalmology Times.

In addition to its role for IOP measurement, the device provides two measures of the biomechanical properties of the cornea: CH and the corneal resistance factor (CRF). These indices are calculated by analyzing the signal derived from the inward and outward applanation events induced by the air-puff.