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:

1. ciliary muscle

2. ciliary processes

3. 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