NOV 30, 2009
By J. Bradley Randleman, MD
Pediatric Ophth/Strabismus, Refractive Mgmt/Intervention
Researchers retrospectively evaluated 18 patients (18 eyes) with keratoconus and contact lens intolerance who were implanted with two 0.45-mm thick Intacs intrastromal corneal ring segments. Patients were evaluated before and six months after surgery using the Ocular Response Analyzer (ORA) and Orbscan II topographer. The authors found that there were minimal changes in ORA values despite significant improvements in corneal topography. Mean values for corneal hysteresis and corneal resistance factor were virtually unchanged, with only two ORA signal parameters changing significantly. The topographic parameters that saw significant decreases were minimum central keratometry (K) (mean change -5.8 D; P < 0.001), minimum central K (mean change -5.8 D; P < 0.001), mean cone location magnitude index from the axial map (aCLMI) (9.6 vs. 7.7; P < 0.009) and mean tangential map cone location magnitude index (tCLMI) (18.9 vs. 12.9; P < 0.002). The only statistically significant biomechanical and topographic parameter correlation was between postoperative ORA infrared signal peak 1 and postoperative aCLMI.
Financial Disclosures
Dr. Randleman is a consultant to and receives lecture fees from Allergan, Inc.