Figure 1. Schematic diagram of experimental setup for feedback-coupled, single-needle, constant-pressure, anterior chamber perfusion in live mice. A 35-G needle for anterior chamber cannulation was connected via a rigid tube to a pressure transducer then to a microsyringe pump, bridge amplifier, and digital input/output (I/O) unit integrated with analytic software on a computer. The pump controller provided a feedback loop between the pressure transducer and the pump and amplifier.