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Ocular Anatomy: Anterior vs Posterior Segment, RetinaChoroidOptic nerveRetinaChoroidOptic nerve
eye_doc 2025. 4. 19. 22:46๐ Ocular Anatomy: Anterior vs Posterior Segment
The human eye is structurally divided into two major parts:
Anterior Segment and Posterior Segment,
separated by the posterior lens capsule / anterior vitreous face.
๐น Anterior Segment
- Structures:
- Cornea
- Iris
- Ciliary body
- Lens
- Chambers:
- In front of the iris: Anterior chamber
- Behind the iris: Posterior chamber
- Fluid:
- Aqueous humor
- Flow: Produced by ciliary body → fills posterior chamber → flows through pupil → fills anterior chamber → drains via trabecular meshwork
- This flow regulates intraocular pressure (IOP) (normal: 10–21 mmHg)
๐ธ Posterior Segment
- Structures:
- Retina
- Choroid
- Optic nerve
- Cavity:
- Vitreous cavity, filled with vitreous humor
- Vitreous Composition:
- Collagen fibers + Hyaluronic acid
- Young eyes: gel state → maintains clarity
- With aging: vitreous liquefaction → collagen clumps → floaters
โ Summary Table
SegmentKey StructuresFluidMain Role
| Anterior | Cornea, Iris, Ciliary Body, Lens | Aqueous humor | IOP regulation, nourishment |
| Posterior | Retina, Choroid, Optic Nerve | Vitreous humor | Light transmission, support |