Which two tonometry methods are commonly used to measure intraocular pressure (IOP)?

• A. Applanation tonometry and non-contact tonometry
• B. Digital tonometry and rebound tonometry
• C. Indentation tonometry and pneumatic tonometry
• D. Visual field test and A-scan

Answer: (A)

Applanation tonometry and non-contact tonometry are widely recognized methods for measuring intraocular pressure (IOP). Applanation tonometry, particularly the Goldmann type, is the gold standard and involves flattening a specific area of the cornea to assess the IOP based on the force required to achieve that flattening. This method allows for a direct measurement of how much pressure is exerting on the cornea and is considered quite accurate.

Non-contact tonometry, often referred to as "air puff" tonometry, provides a method for estimating IOP without making contact with the eye. This technique uses a rapid puff of air to flatten the cornea slightly, measuring the pressure based on how the cornea responds to the air pulse. It's particularly beneficial in practice settings due to its speed and lack of discomfort for the patient.

Together, these methods balance accuracy and patient comfort, making them the go-to choices for IOP measurement in clinical practice.