Anterior segment of eyeball - Eye - Eyeball - e-Anatomy
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Anterior segment of eyeball

Segmentum anterius bulbi oculi

  • Related terms: Anterior segment

Definition

Muhammad A. Javaid

The anterior segment of eyeball refers to the front one-third of the eye that includes structures located anterior to the vitreous body. Structurally, the anterior segment extends from the cornea to the posterior surface of the lens and is filled with aqueous humor.

The anterior segment includes the following structures:

  • Cornea: Transparent anterior fibrous coat of the eye and the major refractive surface.

  • Anterior chamber: The space between the cornea and iris filled with aqueous humor.

  • Posterior chamber: The narrow space between the posterior surface of the iris and the anterior surface of the lens and ciliary body.

  • Iris: Pigmented diaphragm containing the pupil and regulating the amount of light entering the eye.

  • Pupil: Central opening within the iris.

  • Ciliary body: Includes the ciliary muscle and ciliary processes; involved in accommodation and aqueous humor production.

  • Lens: Transparent biconvex structure responsible for refraction and fine focusing of light.

  • Aqueous humor: Clear fluid produced by the ciliary processes that nourishes avascular structures such as the cornea and lens.

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References

  • Rehman I, Hazhirkarzar B, Patel BC. Anatomy, Head and Neck, Eye. [Updated 2023 Jul 24]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2026 Jan. Available from: https://www.ncbi.nlm.nih.gov/books/NBK482428/

  • Standring, S. (Ed.). (2015). Eye (Chapter 42). In Gray's anatomy: The anatomical basis of clinical practice (41st ed., pp. ). Churchill Livingstone.

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