anterior chamber
Summary
The anterior chamber is the fluid-filled space at the front of the eye, between the cornea and the iris. It holds aqueous humor, which nourishes the cornea and lens and helps maintain eye pressure. Light passes through it on its way to the lens.
Detail
Meaning: The anterior chamber lies behind the cornea and in front of the iris and pupil. It is filled with aqueous humor, a clear watery fluid made by the ciliary body. The fluid is secreted into the posterior chamber (between the iris and lens), flows through the pupil into the anterior chamber, and drains at the chamber's edge through the trabecular meshwork into the canal of Schlemm and then the venous blood. Because the cornea and lens have no blood vessels, aqueous humor supplies their nutrients. It also maintains intraocular pressure, which helps the eye hold its shape.
On the MCAT: The term appears in sensation and perception when you trace the path of light: cornea → aqueous humor (anterior chamber) → pupil → lens → vitreous humor → retina, where photoreceptors transduce light. Questions may ask which structure bends light most (the cornea, not the lens) or predict that blocked drainage raises intraocular pressure.
Common confusion: Students mix up aqueous humor and vitreous humor. Aqueous humor is thin, sits in front of the lens, and is continually made and drained. Vitreous humor is a gel filling the large chamber behind the lens, and it helps keep the retina against the back of the eye. The lens is not inside the anterior chamber; it sits behind the iris.
Sources
- Sensation and Perception (Wolfe et al.)
- Psychology (Myers)
Written for the MCAT and checked before it was published. For study reference only. Spotted an error? Let us know.