Intraocular Pressure Measurement

Intraocular Pressure Measurement

Measurement of the intra-ocular pressure (IOP) of the eye is termed Tonometry.

As Intra-ocular pressure is one of the risk factors for glaucoma, it is measured as a routine procedure in a primary eye care examination as a screening and diagnostic tool for the assessment of glaucoma. The IOP values can also be used a measurement of efficacy of glaucoma treatment.

Normal IOP values range from 10 – 21 mmHg. It should be noted that normal IOP values do not necessarily exclude the possible presence of glaucoma.

Clinically, there are two ways IOP can be measured:

  1. Contact Tonometry
    • The cornea is first anaesthetised before the contact tonometer is touching the cornea for a pressure reading in mmHg. (Photo 1)
  1. Non-Contact Tonometry
    • No anaesthesia is required. A small puff of air is sent to the surface of the cornea and a digital device receives and interprets the deflected air for an IOP reading in mmHg. (Photo 2)

(Photo 1)

(Photo 2)