{'fraction_non_alphanumeric': 0.020491803278688523, 'fraction_numerical': 0.003278688524590164, 'mean_word_length': 4.842105263157895, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Preoperative Assessment of Opening and Closing Pressure of Silicone Ahmed Glaucoma Valves

Methods: In 19 consecutive cases of implantation of an AGV, the device was tested for its opening and closing pressure before use. After priming the device as recommended with balance salt solution, the canula with the attached tube of the AGV was connected to an infusion bottle. The bottle height had been adjusted previously so that there was no flow in either direction. Afterwards, the pressure in the infusion bottle was increased gradually using the active infusion pump of an Oertli Phako Machine OS3 until flow through the valve of the AGV was noted (Opening pressure A). Then the pressure was reduced again until the flow stopped (Closing pressure B). Afterwards the pressure was increased again until flow was noted again (Opening pressure C). Intraocular pressure of was then checked postoperatively on the same day. The differences between pressure A B, between C B, and A C were calculated. Means and standard deviations were computed. Low IOP was defined as any value of 4 mmHg or lower. Each of the pressure parameters and the differences was assessed against low IOP (dependent variate) with univariate analyses.