What happens in primary open angle glaucoma?
In primary open angle glaucoma (just called ‘glaucoma’ from now on) there is a partial blockage within the trabecular meshwork. This restricts the drainage of aqueous humour. The reason why the trabecular meshwork becomes blocked and does not drain well is not fully understood. The pressure of the aqueous humour builds up if the drainage is faulty. But, this also increases the pressure on the back of the eye. The increased pressure in the eye can damage the optic nerve (the main nerve of sight) and the nerve fibres running towards it from the retina. The retina contains the ‘seeing’ cells at the back of the eye. The damaged parts of the nerve and retina lead to permanent patches of vision loss. In some cases this can eventually lead to total blindness. What is the difference between increased eye pressure and glaucoma? Glaucoma means that part of the optic nerve is damaged, usually caused by increased eye pressure. But, about 1 in 5 people with glaucoma have eye pressures in the normal
