Evaluation of the Intraocular Pressure Measurement in Patients with Primary Open Angle Glaucoma Using Corvis-ST

Background: The Corneal Visualization Scheimpflug Technology device (Corvis ST tonometry: CST) is a novel noncontact tonometer developed to assess intraocular pressure (IOP) while accounting for the cornea's biomechanical qualities. The aim of this work was to assess reliability and accuracy of corvis-ST tonometer in measurement of IOP in cases of primary open angle glaucoma (POAG).

Methods: This prospective comparative non-interventional study included 70 eyes of patients suffering from bilateral POAG and with clear and virgin corneas. Eyes were divided into two groups: group A (40 eyes of POAG) and group B (30 normal eyes). All patients were subjected to: history taking, examination [visual acuity (VA), slit lamp examination, gonioscopy for angle, posterior segment, optic disc evaluation and IOP measurements] and investigations (Pachymetry and Corvis ST).

Results: There was a significant negative correlation between non-corrected IOP measured by Corvis and corneal biomechanical index in studied glaucoma patients. There is a positive significant correlation between first and second IOP readings by Corvis. This means that the first and second readings of IOP by corvis with interval 30 minutes between the two readings increased together and decreased together (positive relationship).

Conclusions: The IOP measurement in patients with POAG using Corvis-ST has a good reliability.