The Optical Knowledge Portal
Information – Education – Certification


Glaucoma is not one disease but a group of diseases which have in common that they cause damage to the eye’s optic nerve and can lead to total blindness.
One of the greatest risk factors and most common causes of glaucoma is an intraocular pressure (IOP) of more than 21 mm Hg. Continuously elevated pressure inside the eye can pinch or compress the optic nerve head, resulting in the loss of nerve fibres. The pressure increases when the drainage routes for the aqueous humour fluid are blocked, which means more fluid is produced (and remains in the eye) than can drain out of the eye. This often indicates a failure of the trabecular meshwork.
Although the eye can withstand heightened levels of intraocular pressure within a certain range without suffering damage (tension tolerance), the risk of developing glaucoma increases as the pressure rises higher and the longer it remains high.
Since glaucoma often develops slowly and without noticeable symptoms at the beginning, early screening such as genioscopy (use of a three-mirrored lens), funduscopy or ocular tonometry is essential to detect glaucoma and start treatment early on to prevent severe damage to the eye.
Glaucoma is a leading cause of blindness in the world.


Courtesy of

Glaucoma - leading cause of blindness1
Courtesy of