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Background: In an experimental laboratory investigation we compared intraocula r pressure (IOP) measurements obtained by dynamic contour tonometry (DCT), Goldm ann applanation tonometry (GAT), and pneumatonometry (PTG) with intracameral man ometry on human cadaver corneas of different hydration conditions. Methods: Ten freshly enucleated eyes were de-epithelialized. Two tubes were placed in the an terior chamber in opposite directions and connected to a transducer and to a bot tle system filled with balanced salt solution. The pressure in the eye was then adjusted between 5 mmHg and 58 mmHg by electronically altering the height of the bottle. Central corneal thickness (CCT) was registered and IOP measurements wer e obtained with DCT, GAT, and PTG at each manometric pressure reading. Immediate ly after the trial the same corneas were artificially dehydrated and the same me asurement regimen was repeated. Results: In the pressure range defined by the bo ttle height 10-50 cm, IOP values measured by DCT were 0.50 mmHg (95%CI=0.40-0 .60) and 0.36 mmHg (95%CI=0.25-0.47) higher than manometric readings before an d after dehydration, respectively. GAT showed consistently lower values thanmano metry, the difference be ing-3.48mmHg (95%CI=-3.91 to-3.05) and-3.14 mmHg (95%CI=-3.39 to -2.89 ), respectively. Similar results were obtained with PGT, namely differences of- 4.75mmHg (95%CI=-5.21 to-4.29) and -3.98 mmHg (95%CI=-4.48 to-3.48) for t he hydrated and the dehydrated corneal condition, respectively. Only DCT showed no significant change in accuracy between hydrated and dehydrated corneas. Concl usions: In this in vitro study DCT values for IOP were significantly closer to t he manometric reference pressure than those obtained using GAT and PTG, independ ent of the state of corneal hydration.
Background: In an experimental laboratory investigation we compared intraocula r pressure (IOP) measurements obtained by dynamic contour tonometry (DCT), Goldm ann applanation tonometry (GAT), and pneumatonometry (PTG) with intracameral man ometry on human cadaver corneas of different hydration conditions . Methods: Ten freshly enucleated eyes were de-epithelialized. Two tubes were placed in the an terior chamber in opposite directions and connected to a transducer and to a bot tle system filled with balanced salt solution. The pressure in the eye was then adjusted between 5 mmHg and 58 mmHg by electronically altering the height of the bottle. Central corneal thickness (CCT) was registered and IOP measurements wer e obtained with DCT, GAT, and PTG at each manometric pressure reading. Immediate ly after the trial the same corneas were artificially dehydrated and the same me asurement regimen was repeated. Results: In the pressure range defined by the bo ttle height 10-50 cm, IOP values m easured by DCT were 0.50 mmHg (95% CI = 0.40-0.60) and 0.36 mmHg (95% CI = 0.25-0.47) higher than manometric readings before an after dehydration, respectively. GAT showed consistently lower values than mano metry, the difference be ing-3.48 mmHg (95% CI = -3.91 to-3.05) and-3.14 mmHg (95% CI = -3.39 to -2.89), respectively. Similar results were obtained with PGT, ie, differences of- 4.75 mmHg % CI = -5.21 to-4.29) and -3.98 mmHg (95% CI = -4.48 to-3.48) for he hydrated and dehydrated corneal conditions, respectively. Only DCT showed no significant change in accuracy between hydrated and dehydrated corneas. Concl usions: In this in vitro study DCT values for IOP were significantly closer to t he manometric reference pressure than those obtained using GAT and PTG, independ ent of the state of corneal hydration.