How can blocked drainage channels raise pressure inside the eye?

The eye maintains its shape and rigidity through a constant balance between the production and drainage of aqueous humour, a fluid secreted by the ciliary body. Under normal conditions, this fluid flows through the pupil and exits the eye via specialized drainage channels, such as the trabecular meshwork and Schlemm’s canal.12

When these drainage channels become blocked, the fluid cannot exit the eye at the same rate it is produced. Because the ciliary body continues to form new fluid, the accumulation leads to an increase in intraocular pressure. This elevated pressure is a primary risk factor for glaucoma, a group of diseases that can cause permanent damage to the optic nerve and result in vision loss. Whether through degenerative changes in the outflow pathways or physical obstruction of the anterior chamber angle, the inability of the eye to regulate its fluid volume directly results in the dangerous pressure spikes associated with these conditions.12