Intra Ocular Pressure

Goldman Applanation Tonometry

All-Day Phasing

AM Phasing


To measure the pressure of the fluids in the eye. If the pressure is too great, damage may occur to the fragile nerve fibres at the back of the eye. Over time, this may cause a reduction in the vision.


The test is carried out on a slit-lamp using a pressure meter called a tonometer. A drop is placed in each eye containing an anaesthetic and a vegetable dye called fluorescein. With the chin placed on the slit-lamp, the tonometer is brought lightly into contact with the numbed front surface of the eye. The technician will adjust the tonometer to read the pressure measurement. This may be repeated in a phasing test.

How Long Does This Take?

A single pressure measurement takes about 5 minutes. AM phasing will take all of the morning and All Day phasing will take from 9:30 until 16:00