The eyeball consists of three coats or layers: 1. The outer coat includes the sclera and cornea. The sclera forms the white posterior part of the eyeball while the cornea covers the anterior part. 2. The middle coat contains the choroid, ciliary body, and iris. The choroid lies behind the sclera and separates it from the retina. The ciliary body suspends the lens and helps with accommodation. The iris forms the colored circular curtain with the pupil in the center. 3. The inner coat is the retina, which is attached to the choroid on its outer surface and the hyaloid membrane of the vitreous on its inner surface.

1. LAYERS OF
EYEBALL
1. OUTER COAT-
Consists of SCLERA and CORNEA
1. MIDDLE COAT-
Consists of CHOROID,CILIARY BODY
and IRIS
1. INNER COAT-
Consists of RETINA

2. SCLERA
-White part of eye
Forms posterior 5/6th of eyeball
Anteriorly continuous with the cornea at the
sclerocorneal junction or limbus
Deep part of limbus consists of CANAL OF
SCHLEMM
Sclera pierced by-1.optic nerve
2.ciliary nerve and
arteries
3.anterior ciliary arteries
4.choroid veins

3. CORNEA
Transparent and avascular layer
Replaces sclera over anterior 1/6th of
eyeball
Nourished by lymph circulating in
corneal spaces and by lacrimal fluid
Corneal transplantations are common

4. CHOROID
Thin pigmented and vascular layer
Separates posterior part of sclera from
retina
Anteriorly end at orra serrate and
posteriorly perforated by optic nerve

5. CILIARY BODY
Continuous anteriorly to the iris and
posteriorly with choroid
Suspends the lens and helps in
accommodation for near vision
Ciliary muscle consists of
longitudinal,radial and circular fibres

6. IRIS
Forms anterior part of uveal tract
Forms circular curtain with an opening in
centre called PUPIL
Placed vertically between cornea and lens
Divides anterior segment of eye into
anterior and posterior chambers
Contain muscles sphincter pupillae and
dilator pupillae

7. LENS
 Transparent and biconvex
 Separates anterior and posterior segments of
eye
 Contribute 15D to the total of 58D power of
eye
 Elongated cells of lens form fibres which are
arranged concentrically to form lens substance
 Anterior surface is kept flattened by
suspensory ligaments and also retains the lens
in position

8. RETINA
Outer surface attached to choroid and
inner to hyaloid membrane of vitrous
Divided into optic,ciliary and iridial
parts
Area of optic disc is physiological blind
spot and area of highest vision acquity
is fovea centralis
Consists of 10 layers
Supplied by central artery