Abstract
Purpose: :
To characterize the flow parameters of 4 different models of Ex-PRESSTM drainage devices.
Methods: :
Three samples of 4 different models of Ex-PRESSTM drainage devices, the V-50, V-200, X-50 and X-200 were tested. Three measurements per sample were performed. The pressure in an in-series system composed of a microsyringe pump, an electronic pressure transducer and the drainage device plunged in saline solution at 37°C was measured for 4 different flow steps. The slope of the flow-pressure curve gave the resistance to the flow (R) of the device. Modelling of the 4 drainage devices was performed using SolidWorkTM. Flow was simulated using FloWorksTM.
Results: :
Based on the experimental measurements, R for the 3 samples of the V-50 model was 38.03 ± 3.2, 38.38 ± 1.61, and 39.41 ± 0.61 mmHgminml-1 (mean ± SD), respectively. R for the V-200 was 4.82 ± 0.4, 4.86 ± 0.32, and 4.97 ± 0.38 mmHgminml-1, respectively. For the X-50 samples, R was 15.17 ± 0.37, 13.27 ± 0.34, and 11.15 ± 0.33 mmHgminml-1, respectively, and for the X-200 5.78 ± 0.37, 5.86 ± 0.37, and 5.81 ± 0.27 mmHgminml-1, respectively. The computer simulation gave following results: 33.7 ± 0.02, 5.1 ± 0.01, 17.9 ± 0.02, and 6.1 ± 0.01 mmHgminml-1 for the V-50, the V-200, the X-50 and the X-200, respectively.
Conclusions: :
The geometry of the V and X models and the presence of a resistance unit inside the lumen (-50 series) significantly modify the flow characteristics of the 4 models of Ex-PRESSTM drainage devices.
Keywords: computational modeling • clinical laboratory testing • anterior segment