The eyeball has three concentric layers - an outer fibrous layer, middle vascular layer, and inner neural layer. It is divided into two segments, the anterior segment in front of the lens and the posterior segment behind the lens. The anterior segment contains the cornea, iris, ciliary body, and two chambers filled with aqueous humour. The posterior segment contains the vitreous, choroid, retina, and optic disc. Within these segments are numerous structures including the tear film, conjunctiva, sclera, limbus, uveal tract, crystalline lens, and vitreous cavity that work together to provide vision.

1. ANATOMY OF THE EYE
Dr.T.Kurinchi MS

2. GROSS ANATOMY OF THE EYEBALL

3. INTRODUCTION
• Eyeball is a cystic structure, referred as a
globe.
• It is not a sphere but an ablate spheroid.
• It has two pole anterior and posterior pole
• Between these two poles is the equator of the
eye ball.
• Antero-posterior diameter of the eye is 24mm

4. Layers of the Eyeball
It has three concentric layers.
• Outer fibrous layer –cornea, sclera, limbus.
• Middle vascular layer [uveal tract] – iris,ciliary
body,and choroid
• Inner neural layer -retina

5. SEGMENTS
ANTERIOR SEGMENT:
• Consist of cornea to the crystaline lens
• It as two chambers.
• Anterior chamber- from endothelium of cornea to
endothelium of iris.
• ACD is 2.5mm and contains aqueous humour
• Posterior chamber- from iris epithelium [posterior iris]
to anterior surface of the lens.
POSTERIOR SEGMENT : posterior to lens which includes
vitreous, choroid, retina, and optic disc.

6. TEAR FILM
• It has three layers.
• Outer lipid layer, middle aqueous layer, inner
mucin layer.
• It forms the coat over the cornea and
conjuntiva and protects it.

7. CONJUNCTIVA
• It is derived from surface ectoderm.
• It is a translucent mucous membrane which
lines the anterior aspect of the eye ball and
posterior surface of the eyelid.
• Can be divided into three parts:
– Palpabral conjunctiva
– Bulbar conjunctiva
– Conjunctival fornix.

8. CORNEA
• It is transparent, avascular, elliptical in shape , being
12mm horizontally and 11mm vertically innervated by
ophthalmic division of trigeminal nerve.
• Its dioptric power is 44D, Refractory index – 1.34.
It has five layers
• Corneal epithelium, derived from surface ectoderm
• Bowman’s membrane
• Stroma }
• Descemet’s membrane } Mesoderm
• Endothelium }

9. SCLERA
• Dense opaque tough fibrous envelope and covers
the posterior 5/6th of the eyeball.
• It has three layers
Episclera
Sclera proper
Lamina fusca
• Blood supply – episcleral and choroidal vessels
• Nerve supply – Short ciliary nerve posteriorly and
long ciliary nerve anteriorly.

10. LIMBUS
• Junction between cornea and sclera.
• 1 – 2mm in width.

11. ANGLE OF ANTERIOR CHAMBER
• It is anteriorly bounded by corneo-sclera,
posteriorly by root of iris and ciliary body.
• It is aqueous drainage pathway.

12. UVEA
• Anterior: Iris, a free circular diaphragm with central opening called
Pupil.
• Iris separates anterior chamber from the posterior.
• Derived from mesoderm.
• Colour – brown , Pattern – Collarette.
• It has to muscles viz
• Sphincter pupillae – running around pupillary margin, causes
pupillary constriction.
• Nerve: Sensory – Nasociliary N, branch of 5th nerve
• Motor: Occulomotor nerve.
• Dilator pupillae arranged radially near root of the iris – causes
pupillary dilatation.
• Nerve: cervical sympathetic chain.

13. CILIARY BODY:
• Middle portion of uvea composed of ciliary muscles.
• It has two regions viz
• Pars plicata – about 70 plication, has ciliary process
responsible for production of aqueous
• Pars plana – posterior smooth part, safe and
avascular zone for pars plana lensectomy and
vitrectomy procedures.

14. CHOROID
• It is posterior part of uvea.
• This is a vascular sheet which separates sclera
from retina.

15. CRYSTALLINE LENS
• It is transparent biconvex structure derived from
surface ectoderm.
• Dioptric power : 16 – 20mm.
• It is about 9mm in diameter, 4mm in thickness
suspended by suspensory ligament called
zonules.
Structure of Lens:
• Anterior lens capsule
• Anterior lens epithelium
• Lens substance – consists of elongated lens fibres

16. VITREOUS CAVITY
• Contain vitreous humour which transparent
gel like structure.
• Derived from mesoderm.
• It is composed of network of collagen fibres
and hyaluronic acid.

17. RETINA
• Is membranous light sensitive layer of the eyeball.
• It is transparent in life and whitish after death.
• It has ten layers
1. RPE
2. Layers of rods and cones
3. External limiting membrane
4. Outer nuclear layer
5. Outer plexiform layer
6. Inner nuclear layer
7. Inner plexiform layer
8. Ganglion cell layer
9. Nerve fibre layer
10. Internal limiting membrane.

18. NORMAL FUNDUS PHOTOGRAPH

19. • Central retina – 4.5mm in diameter. It extends
from fovea centralis nasally to the optic disc.
• The central part is called Macula lutea.

20. VISUAL PATHWAY

21. THANK YOU