Deep-Sea Environments and the Eye

Abstract

The eye and body are constantly exposed to a constant ambient pressure known as atmospheric pressure. At sea level, atmospheric pressure is approximately 760 mmHg. As one enters the deep-sea environment, the pressure of the water is added to the atmospheric pressure. The increased ambient pressure provides a unique environment for the eye.

As the eye enters the water, a change in refractive power occurs due to loss of the air-tear interface, which is responsible for nearly two-thirds of the refractive power of the eye. Light transmission and color vision are also affected. Patients who have intraocular gas bubbles must be extremely careful to avoid large environmental pressure changes including diving deep into the sea. If an intraocular gas bubble is in place, the pressure-induced changes in the volume of the bubble can result in serious complications, including retinal, uveal, or vitreal hemorrhage, or partial collapse of the globe. Decompression sickness and arterial gas emboli are also serious complications that can affect the vision of deep-sea divers.

The increased ambient pressure of the deep-sea environment results in an increased pressure inside the eye; yet, deep-sea divers don’t experience acute glaucoma. This is the result of increased pressures of all fluid compartments inside the body, including the eye and the cerebrospinal fluid pressure posterior to the optic nerve. Because the intraocular pressure and cerebrospinal fluid pressure increase equally, the translaminar pressure difference does not change, and glaucoma does not result.