XEN implant device versus trabeculectomy, either alone or in combination with phacoemulsification, in open-angle glaucoma patients

Numerical model to predict and compare the hypotensive efficacy and safety of minimally invasive glaucoma surgery devices

“…The present analytical model aims to provide useful information for glaucoma surgeons by modelling the MIGS implants in different scenerios in glaucomatous eyes. This information may be helpful for clinical decision-making and to avoid undesired complications described in previous clinical studies [5][6][7][8][9][10][11][12]. Additionally, as demonstrated by previous studies, these analytical models could predict postoperative IOP, similar to the results found in clinical studies [20,21].…”

“…Interest in the assessing the efficacy and safety of MIGS implants has increased due to the large number of these devices that have been implanted in recent years [7][8][9][10][11][12]. In the present study, we applied a hydrodynamic/numerical model to assess the hypotensive efficacy of three common MIGS devices.…”

“…The influence of various filtration bleb pressures (p b = 2, 5, 10, 17, 25, 34 mmHg) was also assessed. We calculated p b using the formula given below (Formula 1, analytical model section), based on data from clinical studies [7][8][9][10][11][12].…”

“…First, AH production was set as a constant value (2.0 μl/min) even though the flow in the human eye varies during the day, from as high as 2.75 ± 0.63 μl/min [57,58] to as low as 1.4 ± 0.19 μl/ min during sleep [59]. Second, the bleb pressure used in this study, which is an important determinant of implant efficacy, was simulated based on data from previous clinical studies using our analytical model [7][8][9][10][11][12], the exact pressure in the filtration bleb during the postoperative period is currently unknown, so future studies with real bleb pressure are needed. Another limitation is that we set AH outflow resistance as a constant in the model, even though this value is not constant in healthy or glaucomatous eyes since many factors can influence outflow, including IOP and the trabecular meshwork, among others [59][60][61].…”

“…Several studies have assessed the hypotensive efficacy of these MIGS implants, although with relatively short follow-up periods. Data from clinical studies indicate that the hypotensive efficacy varies widely depending on the type of the implant [7][8][9][10][11][12]. Reference values in order to preoperatively predict the highest likelihood reduction in IOP after implantation of these MIGS devices are not available, but could be very useful to help select the device.…”