Understanding the aqueous humor
Updated: Apr 11, 2022
Let’s be honest; some terms relating to our eyes may be more familiar than others. It might be easy to point to the cornea, the dome at the front of the eye which acts as a window on the world. Perhaps most often commented on is the iris, the coloured section of our eyes which helps to control the amount of light reaching the retina. Or there is the pupil, the black section in the centre of the iris which lets the light signals through.
Perhaps less well known is the aqueous humor. And yet without aqueous humor our eyes would have to work very differently, if they worked at all. Quite simply, aqueous humor is the fluid which cleans and nourishes the inside of our eyes at the front whilst at the same time helping them to keep their shape.
The vast bulk of aqueous humor, approximately 99.9%, is made up of water.
The vast bulk of aqueous humor, approximately 99.9%, is made up of water. This is supplemented by a mix of nutrients, vitamins and proteins in order to create a fluid which not only brings nourishment to key areas of the eye but also carries away waste matter. This is particularly important as the lens and cornea have no blood supply which could perform that function. Interestingly it has been shown that when eye injuries occur, the make-up of the aqueous humor can change in order to enhance healing, with the fluid reverting to its usual state once healing has taken place.
In order to provide continuing care for the eyes, aqueous humor is continually produced in the ciliary body which sits in the anterior chamber near the lens, flows into the eyes and then out again via a series of canals behind the iris called the Trabecular meshwork. This continuous flow also helps to maintain a constant pressure of fluid, helping the eye to keep its shape and thereby enabling the individual sections of the eye to work optimally.
Monitoring changes in that pressure can point to a need for intervention and treatment. For example, an increase in pressure could lead to optic nerve damage and glaucoma; one of the prime causes of sight loss in over 60s.
Monitoring changes in that pressure can point to a need for intervention and treatment. For example, an increase in pressure could lead to optic nerve damage and glaucoma; one of the prime causes of sight loss in over 60s. In diabetics increased sugar levels in the blood can damage flow mechanisms, thereby leading to increased pressure levels in the eyes. So much so that diabetics are one and a half times more likely to suffer from glaucoma than the rest of the population; one reason why it is important that diabetics have regular eye examinations. It’s also one reason why we are working on developing screening devices that could help not only to map an individual’s diabetes but also to identify pre-diabetes conditions.