ANATOMY OF UVEITIS

Uvea is intermediate vascular coat of eye ball. It consists of iris, cilliary body and choroid.

The iris consists of two layers of epithelium on posterior surface which are derived from retina embryologically. The stroma is highly vascularized. Iris is thinnest at periphery and is detached easily on trauma. Anteriorly it is lined by an endothelium. From the epithelial cell, two muscle arise. The circular muscle near the pupillary border , sphincter pupillae, which causes constriction of pupil on contraction and is supplied by parasympathetic nerves which come along 3rd nerve. The other muscle near the root of iris is, the dilator pupillae, which caused dilation of pupil on contraction and is supplied by sympathetic nerve fibers.

Ciliary muscle consists of pars plicata and pars plana. The first 2 mm are pars plicata and next 4 mm are pars plana. The Intravitreal injection is usually given at 3.5 mm from limbus in pseudophakic patients and 4 mm from limbus in phakic patients. 

The choroid is richly vascular and is adherent to sclera. There is a potential space between these two called suprachoroidal space.