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Posterior chamber of eyeball

The posterior chamber of the eyeball is a small, narrow space within the eye located behind the iris and in front of the lens. Despite its name, it is not the largest chamber in the eye—that distinction belongs to the vitreous chamber. The posterior chamber is filled with aqueous humor, a clear fluid crucial for maintaining intraocular pressure and providing nutrients to surrounding structures. Understanding the posterior chamber’s anatomy and imaging characteristics is essential in ophthalmology and radiology for diagnosing and managing various ocular diseases.

Synonyms

  • Ciliary body chamber (less common)

  • Posterior aqueous chamber

  • Secondary aqueous chamber

Function

  • Provides a pathway for aqueous humor flow from the ciliary processes, through the pupil, into the anterior chamber

  • Maintains intraocular pressure by regulating fluid dynamics

  • Supplies nutrients and removes metabolic wastes from lens and corneal endothelium

  • Plays a role in maintaining the optical properties of the eye

MRI Appearance

  • T1-weighted images:

    • Appears as a hypointense (dark) narrow space behind the iris.

    • Difficult to visualize unless there is abnormal fluid or pathology

  • T2-weighted images:

    • Appears as a hyperintense (bright) area, as aqueous humor has a long T2 relaxation time

    • The posterior chamber is usually seen as part of the continuous fluid signal with the anterior chamber

  • STIR (Short Tau Inversion Recovery):

    • The aqueous humor remains hyperintense

    • Pathological changes (e.g., blood or exudates) may alter the signal intensity

CT Appearance

  • Appears as a low-attenuation (hypodense) region posterior to the iris and anterior to the lens

  • Not distinctly visualized in the absence of pathology

MRI images

Posterior chamber of eyeball mri image