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Corneal anatomy
Anatomy & Optics
Key Points
- •The cornea has 5 classical layers (6 with Dua's layer): epithelium (50 um), Bowman's (8-12 um, does NOT regenerate), stroma (500 um, 90% of thickness, type I collagen lamellae), Descemet's (3-12 um, thickens with age), endothelium (single layer, does NOT divide)
- •The cornea contributes +43 D of total refractive power (~2/3 of the eye's +60 D); transparency depends on regular collagen spacing, relative dehydration, avascularity, and absence of myelination
- •Corneal endothelium: ~2500 cells/mm2 in young adults; does NOT undergo mitosis - decompensation below 500 cells/mm2 → bullous keratopathy; endothelial pump (Na+/K+-ATPase) maintains deturgescence
- •Limbal stem cells reside in the palisades of Vogt - their deficiency (from chemical burns, SJS, aniridia) causes conjunctivalisation; Schwalbe's line marks the termination of Descemet's and the anterior limit of the trabecular meshwork
- •The cornea is the most densely innervated tissue in the body - supplied by long ciliary nerves (CN V1, nasociliary branch); nerves lose myelin 1-2 mm from limbus; corneal reflex: V1 afferent, VII efferent
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Keep reading Corneal anatomy
13 more sections are included with the Clinical plan.
- Definition
- Epidemiology
- Aetiology and causes
- Pathogenesis
- Classification
- Clinical features