When should visual acuity and pH testing be performed after an ocular chemical splash?

When should visual acuity and pH testing be performed after an ocular chemical splash?

• A. Before irrigation
• B. After irrigation of 1–2 liters
• C. Never test pH
• D. Only after analgesia

Answer: (B)

Immediately start irrigation to dilute and remove the chemical; you don’t wait to test anything. Once you’ve begun irrigation and the ocular surface has been flushed with enough fluid (a practical marker is after about 1–2 liters), reassess. At that point you check the visual acuity to establish a usable baseline for how the injury has affected function and you also measure the surface pH to ensure it has returned to neutral (about 7.0–7.4). Continuing irrigation is guided by persistent abnormal pH, not by pain. Analgesia can be provided for comfort, but testing can be done as soon as the patient can cooperate. Testing before irrigation would miss ongoing injury, and pH testing is essential to know when to stop irrigating and to gauge injury severity.

Immediately start irrigation to dilute and remove the chemical; you don’t wait to test anything. Once you’ve begun irrigation and the ocular surface has been flushed with enough fluid (a practical marker is after about 1–2 liters), reassess. At that point you check the visual acuity to establish a usable baseline for how the injury has affected function and you also measure the surface pH to ensure it has returned to neutral (about 7.0–7.4). Continuing irrigation is guided by persistent abnormal pH, not by pain. Analgesia can be provided for comfort, but testing can be done as soon as the patient can cooperate. Testing before irrigation would miss ongoing injury, and pH testing is essential to know when to stop irrigating and to gauge injury severity.