ophthalmology residency program

1. Development of the eye
and
occular appendages
DR.MOHAMMED MUNEER

2. Embryogenesis
 It is a series of steps that built up on one another ,
each step creates a ripple effect on all subsequent steps
those steps are regulated by genetic programs that are activated in
specific cell types and in a specific order .

3. Eye development
 start day 22 before NT closure
 Lens placode (S.ecto)
 Optic vesicle ( N.ecto )
 Optic stalk
 Optic cup
 Inner (N.retina) , outer ( RPE ) , space
 1st lens , 2nd space to be fill

5. Lens and ant. segment
 Lens palcoede
 Lens pit
 Lens vesicle
 Cornea ( epith )(endo =stroma)


6.  Cuboidal cell
 Ant
 Elongate +profilerate
 1 LF emb n.
 Outer cap.
 Unique ?
 Cap. Prop. ( trans , 4+gag, elas,)
 Lent thick?
 Zonue ( ectomesenchymal)(51/2w)

7. Cornea
 Ecto +N.crest
 39 (2)
 7( periph center)
 71/2 ( FK. 4-5)
 3. ( e2-3, S25-30, D,E)
 E ( N.crest, R , mito )

8. Uvea
 Choroid , ciliary body , iris
 Develops from combination of
( meso , n.ecto , n.crest)
N.crest pigmented epith. Of the uvea
Meso spincter and dilator m.
And non pigmented part of the uvea ( iris
stroma and ciliary m. )

9. Retina and posterior segment

10. Vitreous
 N.ecto 1 vit
 Meso HV
 1(conical +HV)
 4 atrophy
 6 2V
zonules

11. Retina
 NR (inner srface of the cup )
 RPE ( outer srface of the cup )
 Concentrically
( start at the center of the cup and
extend periphrally )
 Lamination occur at 8-12 w of gest.
 1st to differentiate is the ganglion cell
layer (2nd trimester )
 RPE is the only pigmented tissue that
is not drived from n.crest
 Optic n is drived from the optic stack
 Optic stalk is formed by n.ecto
Surrounded by n.crest
 In 6th w of gest
 All CN except ON surrounded by
meninges supplied by schwan cell,
that is why ON is more susceptible optic
neuritis.

13. Sclera
 Drived from meso. +n.crest drived
ectomesenchymal element
 Joins the developing cornea near the
equator
 Continue to expand to surround the
optic cup
 SS and tenon cap. Form later at time
of EOM insertion

14. Orbit and EOM
 Involve contributions fron
ecto.+meso+n.crest
 Interaction btw optic cup +meso
+n.crest is crusial for proper
development and organization of the
EOM.
 4th week of gest. Frontonasal and
maxillary process of the n.crest will
occupy the space that surrounds
optic cups
Bone , cartilage , CT and fat all are
derived from those cells
All bones are mm except the sphenoid
which is cartilagenous
3rd month ossification begins
6th-7th month fusion occurs
 4 recti muscles & superior & inferior
oblique derived From mesenchyme in
the region of the eyeball
Starts as single mass of mesenchyme and
later separate into distinctive muscles
First at their insertion & later at their origins
 Levator palpebrae superioris is formed
last , splitting from the mesenchyme that
forms superior rectus muscle.

15.  4-5 week upper eye lid develop as proliferation of the s.ecto at the area of future outer
canthus.
 2nd month both lower and upper eye lid become as undifferentiated skin folds over the
mesenchyme of n.crest
 Later mesodermal m. Infilterate the eye lid and into palpepral musculature
 10 week of gest. Margin of the fold fuse.
 Evolution of cilia and glands and condensation of the Orbicularis oculi to the fold continues
 Btw 3-6th week of gestation pilosebaceous unit develop from invagination of epithelial cells
into the underlying mesenchyme.
 5th month Adhesion breakdown coincident with secretion of sebum from sebaceous glands.

16.  6-7th week of gest. Lacrimal gland begins to develop
 From basal layer of conjunctiva Solid cords of epithelial cells proliferate in the temporal region
of the fronix
 N.crest derived cells aggregate at the tip of the cords and differentiate into acini
 At 3 months of gestation dusts of the gland formed by vaculation of the cord cells and
develpment of the lumina

18. Questions ??