Tonometry is the measurement of pressure within the eye (called intraocular pressure). Intraocular pressure (IOP) is the pressure exerted against the outer layers by the eyeball.

Tonometry is performed using an instrument called the tonometer (or tonopen). Generally, the doctor will administer a local anesthetic eye drop, such as proparacaine, to numb the eyeball. This allows the veterinarian to examine the eye without alarming the patient and so that the pet does not feel the minor presence of the tonometry instrument.

Tonometry measures the intraocular pressure to diagnose glaucoma. Glaucoma is caused by the buildup of fluid within the eye. Abnormally high pressure can damage the optic nerve, which in turn, leads to vision loss.

Using tonometry, we can also identify low IOP, which may occur with anterior uveitis (inflammation within the eye). Low IOP is also associated with dehydration.

If you have any questions regarding tonometry, please ask a member of our staff.