What is the consequence of increased intraocular pressure on retinal perfusion?

Increased intraocular pressure (IOP) can have a significant negative impact on retinal perfusion. The retina receives its blood supply primarily from the central retinal artery and the choroidal circulation, both of which rely on a pressure gradient for adequate perfusion. When IOP rises, the pressure within the eye can exceed the pressure in these blood vessels, leading to a reduction in blood flow to the retina.

This decrease in perfusion can result in ischemic conditions, where the retinal tissue is deprived of essential nutrients and oxygen, potentially causing damage to retinal cells and impairing vision. Over time, chronic high IOP can lead to conditions such as glaucoma, where the sustained lack of adequate blood flow can contribute to the degeneration of the optic nerve and irreversible vision loss.

The other options suggest either an improvement or no effect on perfusion, which contradicts the well-established physiological understanding that higher IOP hampers blood flow to the retina. Fluctuating perfusion is also not a common direct consequence of increased IOP, as sustained high pressure tends to result in consistently reduced blood flow rather than variability in perfusion.