Glaucoma is a progressive disease of the optic nerve that leads to irreversible visual loss. However, clinical studies have confirmed that early detection and treatment of glaucoma can slow the progression of permanent optic nerve damage and blindness. Glaucoma evaluations involve assessments of several components of the eye.
Intraocular Pressure:
If the pressure of the fluid inside the eye is elevated beyond a normal range, it can lead to damage to the sensitive nerve fibres in the retina which can lead to permanent sight-loss. Intraocular pressure is easily measured to establish whether there is a risk of glaucoma from high pressures. Glaucoma can occur even if the pressures are within the normal range.
Appearance of the Optic Nerve:
Damage to the eye from the pressure of the intraocular fluid involves the area of the retina called the optic nerve head. The optic nerve head is examined closely for signs of damage. The pupils are dilated with an eyedrop to allow for a better view of the optic nerve tissue. The size, colour and symmetry of the right and left optic nerves are recorded.
Visual Fields:
A computerized perimeter randomly presents flashes of light throughout the visual field, and the patient clicks a button whenever each flash is seen. This test can reveal the blind spots caused by the nerve fibres damaged by glaucoma. SITA and SWAP tests are also performed.
Gonioscopy:
Gonioscopy is a precedure that uses a mirroring device in front of the eye to view the internal structure that normally drains intraocular fluid from the eye. Pressure can build up either from poor fluid drainage or the over production of the aqueous fluid. Gonioscopy can identify a risk for increased eye pressure.