ANATOMY &PHYSIOLOGY OF GLAUCOMA
DEFINATION: Glaucoma is a chronic, progressive optic neuropathy caused by a group of ocular conditions which
lead to damage of optic nerve with loss of visual function. The most common risk factor known is
raised intraocular pressure.
Ciliary body: produces aqueous humor
structure:
ciliary muscle
ciliary processes
epithelium: it is both pigmented and non-pigmented
parts
pars plicata: anterior 2mm of ciliary body and secretes aqueous humor
pars plana: posterior 4 mm of ciliary body
angle of anterior chamber
formed by
Aqueous Outflow System
1. Trabecular meshwork: It is a sieve-like structure through which aqueous humor gets filtered
into the canal of Schlemm.
2. Canal of Schlemm: This is an endothelial lined oval channel present circumferentially in the Scleral sulcus.
3. Aqueous veins: They leave the canal of Schlemm at oblique angles to terminate into episcleral veins.
4. Episcleral veins: These are branches of anterior ciliary veins. There is pressure difference of about 5 mm Hg between the anterior chamber and the episcleral veins so that the aqueous drains continuously in them
MAINTENANCE OF NORMAL INTRAOCULAR PRESSURE
Depends upon
1. The formation of the aqueous humor.
2. The outflow of the aqueous humor.
3. The pressure in the episcleral veins
1. The Formation of the Aqueous Humour
i. Secretion—It is an active metabolic process
ii. Ultrafiltration—Its rate is influenced by the level of blood pressure in the ciliary capillaries, plasma osmotic pressure and the level of intraocular pressure.
The Outflow of the Aqueous Humor
The normal outflow takes place by two routes,
i. Angle of anterior chamber (conventional route) 80%
Aqueous is secreted in posterior chamber from here it crossed pupil and enter anterior chamber. It then enters canal of schlemm then aqueous veins and finally into venous circulation
ii. Uveoscleral outflow (unconventional route)
Aqueous exits through ciliary body into choroidal space and choroid