Dynamic Contour Tonometry

Abstract

OBJECTIVE: To compare intraocular pressure measurements obtained by recently introduced dynamic contour tonometry (DCT), Goldmann applanation tonometry (GAT), pneumatonometry (PTG), and intracameral manometry in human cadaver eyes. METHODS: Sixteen freshly enucleated human cadaver eyes were deepithelialized and dehydrated with dextran. A tube was placed in the anterior chamber and connected to a transducer and to a bottle system filled with balanced salt solution. The pressure in the eye was then altered between 5 mm Hg and 58 mm Hg. Intraocular pressure measurements were obtained with DCT, GAT, and PTG at each manometric pressure reading. RESULTS: On average, DCT values measured 0.58 +/- 0.70 mm Hg higher than real intracameral pressure. The GAT and PGT showed consistently lower values, -4.01 +/- 1.76 mm Hg and -5.09 +/- 2.61 mm Hg, respectively. At all bottle heights, DCT values were significantly closer to the reference pressure than GAT and PTG (P<.001). CONCLUSIONS: Measurement with DCT provides IOP values significantly closer to true manometric levels than either GAT or PTG. Further studies are warranted to determine its reliability in patients and the effect of corneal thickness.