[Development of an Oculopressor to Evaluate the Efficiency of Glaucoma Drainage Devices].

Purpose: Evaluation of the long-term efficiency of MIGS implants is still challenging, due to the lack of standardized clinical studies of stand-alone procedures. Moreover, the different mechanisms of the various glaucoma drainage devices are not adequately considered. The current study focusses on the development of a method for oculopression to evaluate the efficiency of glaucoma drainage devices.

Methods: Explanted porcine eyes were subjected to pressure or weight load using three oculopressors with different modi operandi. The time-dependent intraocular pressure was measured using an anterior chamber maintainer. The Honan Balloon exerts variable pressure onto the eye via an air bellows, whereas the Taylor oculopressor applies a defined weight loading on the eye. A novel oculopressor with a weight loading of 60 g was developed and manufactured by means of 3-D-printing.

Results: The intraocular pressure changes observed during the experiments were similar for all tested oculopression devices, varying only in the absolute pressure values. The Honan Balloon was not suitable for the intended purpose, due to poor standardisation of the applied pressure. Oculopression using a defined weight appeared more suitable. The Taylor oculopressor, however, created intraocular pressure values of up to 203.3 ± 38.4 mmHg, which precludes its use with glaucoma patients. On the basis of these data, the new oculopression device was used in a preliminary trial with healthy human subjects, thereby preparing its use in a clinical trial.

Conclusions: Oculopression represents a potentially suitable tool to analyse the efficiency of glaucoma drainage devices. Commercially available oculopression devices are not directly applicable for this task. Difficult handling, high intraocular pressure, and lack of standardisation complicate the use for glaucoma patients. These difficulties were overcome with the newly designed oculopressor that facilitates a well defined increase in intraocular pressure. The device is currently being used in a clinical study to evaluate the efficiency of MIGS implants.