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Choroid anatomy
Anatomy & Optics
Key Points
- •The choroid has the highest blood flow per unit tissue weight of any organ; receives 65-85% of total ocular blood flow; consists of 3 vascular layers: Haller's (large), Sattler's (medium), choriocapillaris (fenestrated capillaries) - supplies the outer 1/3 of the retina (photoreceptors + RPE)
- •Bruch's membrane has 5 layers: RPE basement membrane, inner collagenous, elastic (central, strongest), outer collagenous, choriocapillaris basement membrane - drusen deposit between RPE BM and inner collagenous layer; CNV grows through breaks in Bruch's
- •Blood supply: SPCAs (~15-20, posterior choroid), LPCAs (2, transit to anterior uvea, major arterial circle), ACAs (recurrent branches); drainage: 4-7 vortex veins at the equator → ophthalmic veins → cavernous sinus
- •Choriocapillaris is arranged in lobules (each fed by 1 arteriole); fenestrations face Bruch's membrane; outer BRB is at the RPE level (not choriocapillaris); watershed zones between lobules → ischaemic vulnerability (Elschnig spots, Amalric sign)
- •Pachychoroid spectrum: dilated Haller's vessels (pachyvessels) → RPE dysfunction → CSCR, PPE, PNV, PCV - measured by enhanced depth imaging OCT (EDI-OCT); ICGA is the gold standard for choroidal vascular imaging
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Keep reading Choroid anatomy
13 more sections are included with the Clinical plan.
- Definition
- Epidemiology
- Aetiology and causes
- Pathogenesis
- Classification
- Clinical features