Early detection is the key. Regular eye exams are important, especially after 30 years.

Tests to detect glaucoma

Anesthetic drops are instilled to temporarily numb the eye.

Tonometer or a tonopen is used to take the pressure reading, by touching its footplate on the cornea.

Pressures up to 16 mm of Hg. are considered normal. 16-18 mm are considered as borderline high, require follow up and observation. Above 21mm Hg., definitely requires treatment. 

Pressure is not the only criteria.

This means the ability of each eye to see the center and periphery, without moving it.

This is tested by Automated perimetry machine.

This takes about 20 min for each eye. One eye is covered. The chin is positioned. With the open eye, person is supposed to look at the center. When the lights are seen, the person, presses a switch button, to say 'yes'. Lights are tested in all directions.

This is done using an Ophthalmoscope. The optic nerve is observed. Increased pressure in the eye, damages the optic nerve. This can be seen as hollowing of the nerve, called as increased cup-disc (c:d) ratio. Also small amount of bleeding into the nerve can be seen.

Many new devices are available for better assessment of the optic nerve damage.

Examination of the angle of the eye.

This is done on the slit-lamp, using a special type of lens.