Iris, ciliary body and choroid

Iris

The iris lies in front of the lens and the ciliary body

It separates the anterior chamber from the posterior chamber

Iris

• The stroma connects a sphincter muscle (sphincter

pupillae), which contracts the pupil

• A set of dilator muscles (dilator pupillae) which open it. • Depending on the amount of light, the iris makes the pupil larger or smaller.

Structure of iris The iris consists stroma.

The back surface is covered by an epithelial layer two cells thick (the iris pigment epithelium

The outer edge of the iris, known as the root, is attached to the sclera and the anterior ciliary body

. The iris and ciliary body together are known as the anterior uvea

Just in front of the root of the iris is the region

through which the aqueous humour constantly

drains out of the eye, with the result that

diseases of the iris often have important effects

on intraocular pressure, and indirectly on vision.

Aqueous humour

Blood supply and nerve supply

Constrictor muscles are innervated by parasympathetic fibers of the 3rd cranial nerve

Dilator muscles are innervated by sympathetic fibers from the superior cervical ganglion.

Diseases of iris

Disease of iris

Iritis Inflammation of the iris

Iris (uveitis) Busscca nodule

Berlin nodule

Koeppe nodule Heterochromic iris Iris atrophy Aniridia Iris cyst

Iris melanoma

Aniridia

It is usually bilateral condition in which the whole of the iris is appeared to be missing on external examination

The rudimentary iris, can be visible only by goniocopy It is due failure of anterior growth and differentiation of the optic cup

Symptoms Photophobia Nystagmus Defective vision

Treatment Soft contact lens to reduce photophobia Glaucoma responds poorly to treatment

Typical coloboma

The pupil is pear-shaped with broad base towards the pupillary margin.

Isolated typical coloboma of the iris is rare. It usually extends upto the ciliary body.

Albinism

This is a hereditary disorder of absence or reduction of the melanin pigmentation throughout the body.

The iris looks pink and translucent, owing to lack of pigment The fundus appears orange pink in colour.

Heterochromic iris

It means the two irides show a significant difference in colour. It may be congenital or acquired hepertic uveitis , trauma, acute attack of

angle closure glaucoma.

Ciliary body

It lies between iris and choroid

It contains ciliary muscle and ciliary

processes.

The ciliary muscle takes part in

accommodation

Ciliary process produce aqueous humor.

Aqueous is transparent fluid which nourishes

ocular structure

Flow of aqueous humor

Ciliary process

Posterior chamber

Pupil

Anterior chamber

Trabecular meshwork

Canal of schlemm

Collector channel

Episcleral veins

Blood and Nerve supply

Blood supply : by branches of long posterior ciliary artery and short anterior ciliary artery.

Nerve supply : Naso ciliary branch of 5th cranial nerve

Choroid The vascular sheet separates the sclera from the retina. It is 0.25mm of thick at posterior pole and 0.1mm thick anteriorly

There are 3 layer in the choroid

Outer vessel layer middle vessel layer Inner chorio-capillaries

Diseases of choroid

Choroiditis Choroidal detachment Choroidal coloboma

Choroiditis

Acute multifocal placoid pigment epitheliopathy (AMPPE)

It is unilateral idiopathic disease affecting young adults. It is subacute loss of central vision with typical deep,

cream colored placoid lesions

Investigations: FFA

Treatment : No effective treatment

Serpiginous choroiditis

It is a rare, idiopathic, recurrent disease of the RPE and chorio-capillaries disease.

Chorio retinal inflammatory lesion starts around the optic disc and spreads towards in all directions with out any inflammtory cells in the vitreous.

Investigations: FFA Treatment : No effective treatment

Blood and nerve supply

Short posterior ciliary arteries Two Long posterior ciliary arteries Seven anterior ciliary arteries