What effect does increased intraocular pressure have on aqueous humor dynamics?

Increased intraocular pressure has a significant impact on the dynamics of aqueous humor in the eye, particularly inhibiting aqueous secretion. When the intraocular pressure rises, it creates a feedback mechanism where the production of aqueous humor by the ciliary body is suppressed. This occurs because high pressure within the eye can affect the normal function of the epithelial cells responsible for secreting aqueous humor, leading to alterations in both the availability of nutrients and the regulation of ion transport necessary for aqueous production.

Additionally, elevated intraocular pressure increases the resistance to aqueous humor outflow, primarily via the trabecular meshwork and the uveoscleral pathway. Although the outflow resistance is increased due to the pressure, the initial response of the eye to this pressure spike is a reduction in secretion, which helps to stabilize the overall pressure by preventing further buildup of the fluid.

In summary, when intraocular pressure rises, it inhibits aqueous humor secretion, which is crucial for maintaining homeostasis in the eye and preventing conditions such as glaucoma, where sustained high pressure can lead to optic nerve damage.