The cornea is the clear, dome-shaped front surface of the eye that covers the iris, pupil, and anterior chamber. It's responsible for a large part of the eye's focusing power—about 65–75% of the total.





🧠 Key Functions of the Cornea:

  • Focuses light onto the retina

  • Protects the inner eye from dust, germs, and harmful UV light

  • Acts as a barrier and filter

📚 Anatomical Layers of the Cornea (from outermost to innermost):

  1. Epithelium

    • Thin outer layer (5–7 cell layers thick)

    • Regenerates quickly if injured

    • Acts as a barrier against water, dust, and bacteria

  2. Bowman’s Layer

    • Tough, acellular layer made of collagen fibers

    • Helps maintain corneal shape and adds strength

    • Does not regenerate after damage

  3. Stroma

    • Makes up ~90% of corneal thickness

    • Composed of regularly arranged collagen and keratocytes

    • Transparency depends on the precise arrangement of collagen fibers

  4. Descemet’s Membrane

    • Thin but strong collagen layer produced by the endothelium

    • Acts as the basement membrane for the endothelial cells

  5. Endothelium

    • Single layer of hexagonal cells lining the inner surface

    • Maintains corneal dehydration via active ion pumps (critical for clarity)

    • Cells do not regenerate well—loss leads to swelling and cloudiness

🧬 Blood Supply and Innervation:

  • Avascular (no blood vessels); gets nutrients from tears and aqueous humor

  • Highly innervated by the trigeminal nerve (CN V)—makes it extremely sensitive

Comments

Post a Comment