The inside of the eye contains a clear fluid circulation. If the drainage of this fluid stops working properly, intraocular pressure can rise and lead to glaucoma, a disease in which the nerve at the back of the eye (the ‘optic nerve’) develops progressive damage that can lead to loss of sight.
A cataract is a clouding of part of your eye called the lens. The lens in the eye works like the lens in a camera, focusing light on the ‘retina’, the layer in the eye corresponding to the film in a camera. Vision becomes blurred because the cataract is like frosted glass, interfering with sight. The only treatment for cataract is an operation to remove the cloudy lens and replace it with a plastic lens.
Age-related macular degeneration (AMD) is the most common reason for legal blindness in the developed world. It is classified into a more slowly progressive 'dry' form and a more aggressive 'wet' form. Both affect primarily the centre of the field of vision, so interfere particularly with reading. Ocular injections (usually pain-free!) now give improved or stable sight for many patients.
Dr Brad Bowling