The Goldmann tonometer is widely regarded as the gold standard for measuring intraocular pressure (IOP), but there are several alternative tonometers that can also provide accurate measurements. Here are some notable alternatives:

1. Non-Contact Tonometry (NCT):

   • Description: This method uses a puff of air to flatten the cornea and measure IOP without direct contact.
   • Advantages: It is quick, painless, and does not require anesthesia. It is particularly useful for screening large populations.

2. Applanation Tonometry:

   • Description: Similar to the Goldmann tonometer, this method involves flattening a small area of the cornea to measure pressure. Variants include the Perkins tonometer, which is portable and can be used in various settings.
   • Advantages: Provides accurate measurements and can be used in patients who are unable to sit at a slit lamp.

3. Rebound Tonometry:

   • Description: This method uses a small probe that makes brief contact with the cornea and measures the rebound of the probe to determine IOP.
   • Advantages: It is portable, easy to use, and does not require topical anesthesia. Devices like the Icare tonometer are popular in this category.

4. Dynamic Contour Tonometry (DCT):

   • Description: This technique measures IOP by assessing the contour of the cornea and is less affected by corneal properties.
   • Advantages: It provides accurate measurements in patients with corneal abnormalities and is less influenced by corneal thickness.

5. Ocular Response Analyzer (ORA):

   • Description: This device measures the biomechanical properties of the cornea and provides two IOP values: IOPcc (corneal compensated IOP) and IOPg (Goldmann equivalent IOP).
   • Advantages: It is useful for assessing patients with corneal disease and provides additional information about corneal elasticity.

6. Tono-Pen:

   • Description: A portable, handheld tonometer that uses applanation principles to measure IOP.
   • Advantages: It is convenient for use in various settings, including at the bedside, and is particularly useful for patients who cannot be examined at a slit lamp.

7. Schiøtz Tonometer:

   • Description: This is a mechanical tonometer that uses a weighted indentation method to measure IOP.
   • Advantages: It is simple and inexpensive, though it requires proper technique and interpretation.

Each of these alternatives has its own advantages and limitations, and the choice of tonometer may depend on the clinical setting, patient characteristics, and specific needs of the examination. For accurate IOP measurement, it is often recommended to use multiple methods, especially in cases where corneal properties may affect the readings.