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Topic

design image
lens of the eye

The lens of the eye, also called the crystalline lens, is a transparent, biconvex structure located directly behind the iris and in front of the vitreous body. It plays a critical role in focusing light onto the retina, facilitating clear vision at various distances. The lens is avascular, composed mainly of water and proteins arranged in precise layers, and is suspended by zonular fibers (suspensory ligaments) attached to the ciliary body.

Synonyms

  • Crystalline lens

  • Ocular lens

  • Eye lens

Function

  • Focuses light rays onto the retina for clear vision (accommodation)

  • Changes shape to adjust focal distance (accommodative power)

  • Separates the anterior segment (aqueous humor) from the posterior segment (vitreous body) of the eye

MRI Appearance

  • T1-weighted images:

    • The lens appears low signal intensity (dark) due to its highly organized, low-water, protein-rich structure.

  • T2-weighted images:

    • The lens shows very low to low signal intensity (dark), often darker than surrounding aqueous and vitreous humor.

  • STIR (Short Tau Inversion Recovery):

    • The lens remains dark (hypointense), similar to other sequences, due to suppression of signal from water and fat; helps delineate the lens against adjacent high-signal fluids.

CT Appearance

  • The lens appears as a well-defined, slightly hyperdense (brighter) biconvex structure posterior to the iris.

  • Typically has a higher attenuation than the vitreous humor, making it easily identifiable.

MRI images

Lens mri image t2 sagittal

MRI images

Lens mri image