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Corneal cross-linking biomechanics evaluated by a novel and easily implemented differential tonometry method

Poster Details

First Author: S.McCafferty USA

Co Author(s):    M. Wang   J. Berdahl                 

Abstract Details


Evaluate corneal changes following corneal crosslinking (CCL) by paired differential tonometry intraocular pressure (IOP) measurements with a Goldmann tonometer (GAT) prism and corneal compensating, correcting applanation tonometry surface (CATS) prism.


Clinical prospective, open-label, randomized, controlled, reference device comparison


IOP was measured on 18 unique eyes undergoing CCL 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.


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 CCL (p=0.005,0.015). CH initially decreased at two weeks post-CCL then returned to sustained pre-op levels (p=0.033,0.20). CCT progressively decreased following CCL (p=0.002).


Differential tonometry between standard GAT and corneal biomechanical compensating CATS prisms demonstrates it as a simple and sensitive method for measurement of changes in corneal rigidity and corneal stress redistribution.

Financial Disclosure:

has significant investment interest in a company producing, developing or supplying product or procedure presented

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