Abstract
Purpose :
Evaluate corneal changes following corneal crosslinking (CXL) by paired differential tonometry intraocular pressure (IOP) measurements with a Goldmann tonometer (GAT) prism and corneal compensating, correcting applanation tonometry surface (CATS) prism.
Methods :
Design: Prospective, controlled, open-label reference device comparison
Methods: IOP was measured on 23 unique eyes undergoing CXL for keratoconus with a GAT using a standard flat GAT prism and a curved corneal error correcting CATS prism before treatment and at 2 weeks, 2 months and 6 months after treatment. Concurrent measurements of central corneal thickness (CCT) and corneal hysteresis (CH) were completed.
Results :
Randomized paired IOP measurements with standard GAT and corneal correcting CATS prisms indicated a significant sustained relative increase in the differential IOP between the two prisms after CXL (p=0.005,0.015,0.001). CH initially decreased at two weeks post-CXL then returned to sustained pre-op levels (p=0.033,0.20,0.20). CCT progressively decreased following CXL (p=0.005).
Conclusions :
Differential tonometry between standard GAT and corneal biomechanical compensating CATS prisms demonstrates a simple and sensitive method for measurement of changes in corneal rigidity and corneal stress redistribution. Results suggest that CXL likely re-establishes a more “normal” biomechanical behavior to the keratoconic cornea.
This is a 2021 ARVO Annual Meeting abstract.