How many times should you tap the cornea when using a tonopen?

When assessing intraocular pressure using a tonopen, the recommended practice is to tap the cornea four times. This method allows for an accurate measurement of the eye's pressure, as multiple readings help in averaging out any inconsistencies or fluctuations caused by factors such as patient movement or variable corneal surface conditions.

The tonopen utilizes a soft tip that lightly makes contact with the cornea, and performing four taps ensures that the device can gather enough data points to produce a reliable result. This thorough approach minimizes the risk of outliers that could arise from a single tap, thus enhancing the overall reliability of the measurement.

Tapping fewer times, such as two or three, may not yield a sufficiently accurate or reliable intraocular pressure reading, while five taps may be unnecessary and could be uncomfortable for the patient. The practice of four taps strikes the right balance between obtaining dependable data and ensuring patient comfort.