Corneal elasticity as a measure of intra-ocular pressure: a controlled clinical examination.

Abstract

PURPOSE: To determine the clinical efficacy of corneal elasticity (CE) measurements as an index of intra-ocular pressure(IOP). The considerable body of evidence linking elevated intra-ocular pressure (IOP) to glaucomatous conditions, points to the importance of the accurate and reliable measurement of IOP for diagnosis, prevention and post treatment assessments. Recently an applanation resonator sensor (ARS) for measuring IOP via CE has been proposed as an alternative to the extant Goldmann applanation tonometry (GAT). The present study examines the validity of the measure as an index of IOP in glaucomatous patients. METHODS: A structured sample of glaucomatous patients and orthogonally matched normal control subjects were assessed by the GAT and ARS methods in the research and outpatient treatment laboratory of the university Ophthalmology Department. The patient sample consisted of individuals with IOP of 16 mmHg and above and with evidence of clinically significant optic nerve damage. RESULTS: Significant correlations between GAT-IOP and ARS frequency shifts (Delta fs) for both clinical (r=.88, p<.001, n=16) and normal subjects (r=.60, p<.01, n=16) were obtained. CONCLUSIONS: The results suggest that ARS could be a clinical alternative to the extant GAT method in assessing IOP. In order to further examine the clinical efficacy of ARS-Delta fs as an accurate index of IOP, tests of a significant correlation between ARS-Delta fs and manometrically established vitreous IOP are now needed in normal and glaucomatous subjects.