The eye begins developing at 3 weeks and is formed from contributions of both ectodermal and mesodermal tissues. The optic vesicle forms from the forebrain and invaginates to form the optic cup, which later develops into the neural retina. The surface ectoderm thickens to form the lens placode which then invaginates to form the lens vesicle. The lens vesicle develops into the lens, while the optic cup develops into the neural retina. Surrounding mesoderm develops into structures like the sclera, choroid, ciliary body and iris. The eye continues developing through the 10th week of gestation.

1. DEVELOPMENT OF
EYE
DR NEETA CHHABRA

2. Development of Eye
• Begins at 3rd week and continues through the
tenth week
• Cells from both ectodermal & mesodermal
tissues contribute to the formation of eye
• Ectoderm : Surface ectoderm
Neuro ectoderm
• Mesoderm : Extracellular mesenchyme which
consists of both, the neural crest cells and
mesoderm
• Endoderm does not take part in formation of
Eye

3. Formation of Optic vesicle
• At 22nd day of IUL, neural plate destined to
form prosencephalon shows thickened area
on each side that becomes depressed to
form Optic sulcus
• Optic sulcus bulges outwards to form Optic
vesicle
• Proximal part of optic vesicle becomes
constricted and elongated to from Optic
stalk

4. Formation of Lens vesicle
• As the optic vesicle comes in contact with
surface ectoderm, it thickens : Lens placode
• Lens placode depresses to form Lens pit &
later, Lens vesicle
• Lens vesicle loses contact with surface
ectoderm by 33rd day

5. Formation of Optic cup
• Optic vesicle is converted into a double
layered structure : Optic cup
• This is due to differential growth of walls
of the optic vesicle
• The optic cup grows over the upper &
lateral side of lens & not on the inferior
aspect leading to a gap : Choroidal fissure
or fetal fissure

6. Changes in Associated Mesoderm
• Developing neural tube is surrounded by
mesoderm, that differentiates to form:
Superficial fibrous layer : Dura mater
Deep vascular layer : Pia-arachnoid
• This mesoderm covers optic vesicle also

7. Mesenchyme
• A part of this mesoderm along with
blood vessels is carried into the optic
cup through choroidal fissure: hyaloid
vessels
• Distal part of vessels degenerate,
proximal part form central artery &
vein of retina
Changes in Associated Mesoderm

8. • Lens vesicle: Lined by a single layer of
cuboidal cells
• Cells of ant wall remain cuboidal: Epithelium
• Cells of post wall elongate, become
columnar & obliterate the cavity of the lens
vesicle
• They lose their nuclei & form primary lens
fibers
• New lens fibers are formed from equatorial
cells of anterior part which later become
hard & form secondary lens fibers & lens
grows
Development of Lens

9. Development of Retina
• Develops from optic cup : Neuroectoderm
• Optic cup has 2 parts: Anterior & Posterior
• Anterior part : Thin, forms ciliary & iridial
parts of retina
• Posterior part : Thick, forms various layers
of retina. It has 2 walls
• Outer wall: Pigmented layer of retina
• Inner wall : Nervous layer of retina

10. Retina & Optic Nerve
• Inner wall: Differentiates into 3 layers
• Matrix layer : Forms rods and cones
• Mantle layer: Forms bipolar cells, ganglionic
cells, other neurons & supporting tissue
• Marginal layer: Axons of ganglion cells
converge towards optic stalk & forms Optic
Nerve

11. • During embryonic & early foetal life, pigment
& neural layers of retina are separated by intra
retinal space which represents the original
cavity of the optic cup
• Before birth this space is obliterated due to
proliferation of cells of inner layer
• Thus, rod & cone cells come in contact with
pigment layer of retina
Development of Retina

12. Sclera and Choroid
• During 6th or 7th week of IUL mesenchyme
surrounding external surface of optic cup condenses
into two layers:
Outer fibrous layer: Sclera
Inner vascular layer : Choroid
• Sclera is continuous anteriorly with substantia propria
of cornea & posteriorly with dura mater
• Choroid is continuous anteriorly with ciliary body &
iris & posteriorly with pia arachnoid

13. Ciliary Body
• Derived from forward prolongation of
mesoderm forming the choroid
• Epithelium : Two layers of Optic cup
Outer pigmented layer : Pigmented layer
of choroid
Inner non pigmented layer : Neural layer of
choroid
• Stroma,ciliary muscle & blood vessels :
Vascular mesoderm

14. Iris
• Derived from forward prolongation of
mesoderm forming the choroid
• Epithelium : Two layers of Optic cup
Outer pigmented layer : Pigmented layer of
optic cup
Inner non pigmented layer : Neural layer of
optic cup
• Stroma & blood vessels : Vascular mesoderm
• Muscles : Neuroectodermal cells of optic cup

15. Cornea
Cornea consists of 5 layers
• Outer Stratified squamous epithelium:
Surface ectoderm
• Bowman’s membrane & Lamina propria:
Mesoderm
• Descemet’s membrane & inner corneal
epithelium: Neural crest cells

16. Anterior & Posterior Chambers of Eye
• Anterior chamber : Splitting of Mesoderm
between iris & cornea
• Posterior chamber : Splitting of Mesoderm
between iris & lens
• Filled with aqueous humour secreted by
ciliary processes of ciliary body
• Communicate with each other after
disappearance of pupillary membrane
• Aqueous humour is drained by canal of
Schlemm

17. Vitreous
• Vitreous develops as follows:
• Primary vitreous develops from mesoderm
It is vascular having hyaloid vessels
• Secondary vitreous is secreted by
neuroectoderm of optic cup. It is avascular
• Secondary vitreous replaces the primary
vitreous

18. Eyelids
• Develop from reduplication of surface
ectoderm
• Muscles & tarsal plates : Mesoderm
• Folds grow & fuse with each other
• Space enclosed within folds : Conjunctival
sac
• Conjunctiva : Ectodermal origin
• Eyelids remain fused till 7 month of IUL

19. Lacrimal Apparatus
• Lacrimal Gland: Develops from 15 to
20 buds from the superolateral angle
of conjunctival sac
• Lacrimal sac & Nasolacrimal duct:
Develop from ectoderm of
Nasolacrimal furrow
• Lacrimal canaliculi develop from
canalization of ectodermal buds that
grow from medial ends of each eyelid
into lacrimal sac

20. Extraocular Muscles
Mesenchymal condensation
(Pre occipital myotomes)

21. Anomalies of Eye
1. Anophthalmia
2. Microphthalmia
3. Synophthalmia
4. Cyclopia
5. Proboscis

22. Anomalies of Lid & Lens
1. Entropion
2. Ectropion
3. Coloboma of eyelid
4. Coloboma of iris
5. Epicanthus
6. Aphakia
7. Congenital Cataract

23. Summary
Part Source
Sclera Mesoderm
Choroid Mesoderm
Retina Neuroectoderm (Optic cup)
Lens Surface ectoderm
Vitreous Primary (Mesoderm)
Secondary (Neuroectoderm)
Ciliary body Mesoderm
Epithelium : Optic cup (Neuroectoderm)
Ciliary muscle Mesoderm
Iris Mesoderm
Epithelium : Optic cup (Neuroectoderm)
Sphincter & dilator
pupillae
Neuroectoderm ( Optic cup)
Cornea Surface epithelium (Ectoderm)
Rest of the layers (Mesoderm)
Conjunctiva Surface ectoderm
Optic nerve Neuroectoderm
Coverings (Mesoderm)

24. THANKS