In phacoemulsification, which of the following describes the mechanism of action of the aspiration port in maintaining the anterior chamber stability?

Explanation

## Anterior Chamber Stability in Phacoemulsification **Key Point:** The anterior chamber is maintained by a dynamic balance between *positive pressure infusion* (through the irrigation port, typically at the 12 o'clock position) and *negative pressure aspiration* (through the phaco handpiece). This equilibrium keeps the chamber at physiologic depth, preventing collapse or shallowing. **High-Yield:** Chamber stability depends on the ratio of infusion to aspiration flow rates. If aspiration exceeds infusion, the chamber shallows; if infusion exceeds aspiration, the chamber deepens. Modern phaco machines use automated flow control to maintain this balance. ### Mechanism of Chamber Stability ```mermaid flowchart LR A[Irrigation Port<br/>Positive Pressure<br/>Infusion] -->|Balance| C[Anterior Chamber<br/>Stable Depth] B[Aspiration Port<br/>Negative Pressure<br/>Removal] -->|Balance| C C --> D[Optimal visibility<br/>& endothelial protection] ``` **Clinical Pearl:** If the chamber shallows during surgery (aspiration > infusion), the surgeon must either increase infusion rate or decrease aspiration rate. Persistent shallowing risks corneal touch, zonular damage, and endothelial cell loss. **Warning:** A common misconception is that aspiration alone maintains the chamber — in fact, aspiration *removes* fluid and must be counterbalanced by infusion to prevent collapse.