Ophthalmology & Optometry/Glaucoma
How can high pressure within aqueous humor,the space between cornea and eye lens, damage optic nerve since they do not come in contact with each other?
There are several theories about how optic nerve damage from glaucoma occurs. Assumming we are considering the 'high pressure' model, as opposed to a vascular or mechanical model, the intraocular pressure is evenly distributed throughout the eyeball not just where the fluid is produced. The pressure tested in the front of the eye is just as great as the pressure pressing on the optic nerve head in the back of the eye. Think of measuring pressure of a tire by sampling at the valve. The normal path for the aqueous is convoluted: it is produced in glands behind the lens, flows towards the front of the eye by flowing around the peripheral edges of the lens and then between the lens and iris through the pupil and finally exits through the 'angle' between the cornea and iris into blood vessels. The aqueous is not the wet tears that keep the eye moist.
Hope that helps,
Mitch Axelrod, OD