2. EYEBALL
Cystic,near to roof & lateral wall,Albate spheroid
Diamensions~Diameters AP 24mm,Horizontal
23.5mm,Vertical 23mm,Circumferance 75mm,Volume
6.5ml,Weight 7 gm
Two poles~Anterior & Posterior
Three Equators~Geometric,Anatomical,Surgical
Three Axes~Optical,Visual,Fixation
ThreeVisual angle~Alpha,Gamma,Kappa. Only Kappa
can be measured
Three coats~Outer fibrous,MidVascular,Inner Nervous
Two Segments~Anterior & Posterior
Two Chambers~Anteror & Posterior
3.
4.
5. Introduction
The eyeball and its related structures are derived from
following Four primordia ;
1. Neuroectoderm~outgrowth from procencehalon ,optic
vesical
2. Surface Ectoderm~lens placode and surrounding
accessory ocular structures
3. Mesodem~surrounding optic vesicle
4. Visceral mesodem of maxillary process
Derived from germ layers
Ectoderm(2st)
Mesoderm(3rd)
Endoderm(1nd)
First evidence of primitive EYE during 3rd week(day 22)of
gestation,embryo~2mm length with 8 pairs of somites
6. Embryology and regularity factors
In embryology various endogenic regulatory factors controls cellular
differentiation, proliferation, cell migration and inductive
interaction for the specific organ development.
Three groups of regularity factors are identified
1.Growth factors
2.Homeobox genes/ master
genes
3.Neural crest
cells
fibroblast
growth
factors(FGF)
transforming
growth factors
Bs
insulin
like growth
factors (IGF-I)
control subordinate genes
in regulation of patterns
of anatomical
development(morphogen
esis) eg. PAX6-marks the
location of lens, HOX (
HOX8.1 –corneal
epithelium,HOX7.1-
ciliarybody)
Transient
population of
pluripotent cells,
originated from
neuroectoderm
which latter
transforms into
mesenchymal cell
9. GASTRULATION-early 3rd week
formation of three germinal layers
Begins with primitive streak by 15th day
Primitive streak~visible as a narrow groove with
slightly bulging regions on either side in median
plane caudally on dorsal aspect of embryonic
disc with slightly elevated area on cephalic
end,primitive node.
Epiblast cell migrates to primitive
streak,become flask shaped and detach,migrate
below epiblast
That replace hypoblat form endoderm and then
form mesoderm.Remaining epiblast form
12. Neuraltion and neural tube formation
Neural tube is an important primitive structure from
which ocular primordia-the optic vesicle, the
progenitor mesenchymal cell (from neural crest) and
neural tissue develops
Begins as notochord develops,it induces overlying
embryonic ectoderm in midline to thickened forming
Neural plate(16 day of gestation) and that ectodem
called neuroectodem
Neural plate form Neural groove on 18 day of
fertilization and elevation of two side of neural groove
forms neural fold,adjacent neural plate part form
neural crest and ultimately fold fuses to become
neural tube(22 day) and neural crest cells
13. Neuraltion and neural tube
formation-22th day Neural
crest cell
Gartrula Neural grove
14. Neuraltion and neural tube formation-22th day
1.Neural
plate
2.Neural
groove
3.Neural
tube Neural crest cell-
proginater cells for
mesenchymal cells
Surface
ectoderm
15. Formation of eye primordia-3rd
week
Primitive eye starts in 3rd week of gestation when
anterior portion of neural tube is folding
As the neural tube is folding 3 dilatation appears at the
anterior portion of neural tube-forebrain
(procencehalon), midbrain and hindbrain
Primitive eye originates as Optic primordia,thickening
area on either side of midline on neural plate that
destined to form procencehalon (venterolateral region
of primitive forebrain)
16.
17. Formation of optic and lens vesicle
Begins with the optic primordia that depressed to
form optic sulcus then wall of optic sulcus deepens
and wall of procencephalon overlying sulcus bulge to
form Optic vesicle,proximal part become constricted
and elongated to form optic stalk
With the formation of optic vesicle(25th day of
gestation) it induce surface ectodermal cells,in contact
laterally,thicken to form Lens Placode at 27 day of
gestation(embryo 4-4.5mm)
Lens Placode convert into LensVesicle
LensVesicle seprate from surface ectoderm at 33 day
of gestation
18.
19. By end of 3rd week gestation
Three primordial structure are
formed:
1. Lens placode
2. Optic vesicle
3. Mesoderm surrounding
the optic vesicles
20. Optic cup formation
During Fourth week(embryo-7.6-7.8mm) of gestation
OpticVesicle converted to Optic cup by differential
growth of wall of OpticVesicle
Margin of Optic cup grow over lens vesicle from upper
and lateral side but such growth doesn’t occur from
inferior side forming Choroidal or Embryonic fissure
Choroidal Fissure closes by 6th -7th week of
gestation,when failsTypical Colobomata result
By 7th week of gestation,most basic structure of eye
are present
21. Concept of congenital anomalies
Developmental anomalies Occurs due to disturbance
in embryonic events by various factors in 1st -3rd
months of pregnancy, ocular structures are most at
risk in the period of organogenesis from 18 – 60 days
1. Intrinsic factors 2.extrinsic factors(teratogen)
Altered, defective or imperfective
genes
Impaired cellular
induction/proliferation
Defective cell migration
Inadequate differentiation & cell
death
Infection (Rubella, syphilis,
cytomegalovirus, herpes simplex
virus )
radiation
Maternal diseases(eg.Diabetes)
Drugs/toxins-
alcohol,thalidomide,antiseizure,retino
ic acid ets
23. Formation of lens
Derived from surface ectoderm
With the formation of optic vesicle the surface
ectoderm in contact with optic vesicle thicken and forms
lens plate/lens placode-27th day
Eventually the lens plate invaginates and separates
from surface ectoderm and forms lens vesicle -33rd day
24. Lens vesicle
Lens vesicle has anterior wall with cuboidal
epithelial cell and posterior columnar epithelial
cells
Synthesize type 1v collagen
& gylcosaminoglycans to
form lens capsule,
maintains homeostatic
fuction of cell and
equatorial cell serves as
progenitors for 2ndary lens
fibers layed concentrically
throught life
Forms primary lens fiber
filled with protein crystalline
- embryonic nucleus
25. Cells of posterior wall lengthens and form elongated
fiber that projects into the lumen and specific lens
protein(crystalline) are synthesized make them
transparent,nuclei disappears
Posterior cell contributes for most of the growth of lens
for first 3 month-preserved as compact zone of lens,
embryonic nucleus.
26.
27. From 3rd month the anterior progenitor
cells proliferates and produce 2ndary lens
fibers also called fetal nucleus upto 8th
month of gestation
In 3rd month inner most fibres mature with
increase in cytoplasmic fibrillar materials
and the cell nuclei and organelles decreases
Secondary fibers are displaced inward
between the capsule and embryonic
nucleus and meets on vertical planes to
formY shape suture anteriorly and inverted
Y posteriorly & complicated dendritic
pattern is observed in infantile and adult
nucleus as growth of lens fiber assymetric
following birth
28. Lens~8.8-9.2 mm diameter
At birth it weighs 65mg (adult at 80 yr-258mg)
with thickness of 3.5mm ( adult-5mm)
Lens fiber are formed throughout the human life
developing into different layers of lens fibers
29. Lens anomalies
!
1.Congenital aphakia-absence of lens at birth
primary aphakia Secondary aphakia(more common)
Occurs due to failure of
tissue migration from
surface ectoderm
Occurs due to spontaneous
absorption of developing
lens
2.Lenticonus and lentiglobus- localised cone
shape or spherical deformity of lens surface
Associated with Alports syndrome-X-
linked disease(lenticonus anterior)
characterized by defective genes for
production of type 1V collagen
30. Lens anomalies
Limited to either Embryonic or Foetal Nucleus
Most are Idiopathic
Herediatery-AD(most common),AR,X linked
Genetic a & metabolic disorders-Down syn,
marfans syndrome,galactosaemia etc.
Maternal infection and toxicity- rubella(during 1st
trimester), CMV, varicella, radiation,steroids,
thalidomide , toxoplasmosis etc.
Lamellar (zonular) Cataract~most common,
50%,Involve Foetal Nucleus.
4.Congenital cataract-etiology
3.Lens coloboma-
flattening/notching(lower quadrant of
equator) of lens due to absence of zonular
fibers, associated with defect in iris, optic
nerve/ retina as a result of abnormal closure of
embryonic fissure
31. Cotn….
Congenital Ectopic Lentis~displace lens from normal
position(patellar fossa)
A. Simple ectopic lentis-Bilateral,symmetric,upwards
AD inheritance
B. Ectopic lentis et pupillae
C. Ectopic lentis with systemic anomalies
Marfan’s Syndrome-AD,displace upward and temp
Homocystinuria-lens subluxated downward and
nasally
Microspherohakia~lens spherical & small in size,
occur isolated or feature of syndrome e.g.Weil-
Marchesani Syndrome or Marfan syndrome
32. Development of cornea-begin at 40th day
of gestation & by 5-6th month atain almost adult app
Development of cornea is induced
by lens and optic vesicle
formation
With the separation lens vesicle
the surface ectodermal cell
proliferates to form epithelium of
cornea
Basal lamina of epithelium cells
secrets collegen fibers and
gycosaminoglycans to form
primary stroma
Corneal
epithelium
Lens vesicle
Surface
ectoderm
33. Corneal embryogenesis-5th week
By early 5th week gestation there are
3 waves of mesenchymal
cells(Neural crest derived) migrating
towards the corneal epithelium.
1st mesenchymal wave forms the
corneal &Trabecular endothelium .
Desment’s membrane is derived
from the basal lamina of
endothelium
Corneal Nerve present by 5th month
of gestation
Foetal Cornea very Hydrated
compare to Adult So translucent
rather than transparent
34. Ctn…
2nd mesenchymal wave
migrates between epithelium
and endothelium and forms
keratocytes or fibroblast
The keratocytes synthesis type 1
collagen fibers and
proteoglycans(matrix) which are
organized as lamellae to form
stroma of cornea
Bowman’s layer~condensation
of superficial accellular part of
stroma(after 4th month & fully
develop at birth)
35. Corneal derivatives
Diameter at birth –10 mm( 9.5-10.5mm)reaches
adult size 12 mm by 2 years
Derived from surface
ectoderm
Derived from
mesenchyme(neural
crest cell)
Derived from
mesenchyme(neural
crest cell)
36. Developmental anomalies-cornea
Due to fetal arrest of corneal growth in 5th month or
related to the overgrowth of anterior tips of optic cup
which leaves less space for cornea to develop
Inherits as autosomal dominant/recessive trait
Due to failure of optic cup to grow leaving large space
for cornea to fill
Associated with abnormal collagen production-Marfan
syndrome
Inherits as X-linked recessive pattern
1.Microcornea:
Corneal horizontal diameter is less than 10mm
since birth
2.Megalocornea
Corneal diameter more tha 12mm at birth or more
than 13mm after 2 years
37. Disorder of 2nd wave mesenchymal migration
90% bilateral & cornea whole or sometimes only
periheral cornea affected
Sporadic but both autosomal dominant and recessive
inheritance pattern are reported
Endothelial dystrophy-Primary dysfunction of 1st
mesenchymal wave/corneal endothelial cell
degeneration. Autosomal recessive>dominant.
Stromal dystrophy –dysfunction of corneal stroma
causing corneal opacity.
Causes of CongenitalCloudy Cornea~Sclerocornea,tear
in descement membrane,ulcer,metabolic conditions
(STUMED)
3.Sclerocornea-
Sclera like clouding of cornea with ill-defined limbus.
Difficult to differentiate cornea and sclera
4.Corneal Dystrophy
Diffuse,ill defined flaky/featheary/blue-gray ground
glass opacification of cornea.Cornea is clearer
peripherally
38. Corneal thinning and bulging due stromal and epithelium thinning,
fragmentation of Bowman’s layer and folds or break in Descement’s
membrane
Etiology unknown, usually multifactorial associated with Down
syndrome, mental retardation and atopic diseases
Non inflammatory,Bilateral 85%,usually start at puberty & progress
slowly
Defective Synthesis of Mucopolysaccharide & collagen tissue
5.keratoconus-
Condition in which central cornea assume a conical shape
39. Anterior chamber and angle formation
By beginning of 3rd week there are three successive in
growth of mezenchymal cell surrounding the optic
cup
1st wave of mezenchye forms corneal endothelium
&Trabecular endothelium, 2nd waves forms Corneal
stroma & Pupillary membrane & 3rd wave forms Iris
stroma
Anterior chamber is first recognized as split like space
between developing corneal endothelium and iris
epithelium as a result of selective mezenchymal cell
atrophy/cleavage
Anterior Chamber appears- 3rd Month of Gestation
40. Anterior chamber and angle formation
~anterior chamber depth determined genetically with Dominant
Inheritance
1stMesenchymal wave
form corneal &
Trabecular
endothelium
2nd wave forms
pupillary membrane&
Corneal stroma
3rd wave forms
Iris Stroma
Primitive
anterior
chamber-slitlik
space
41. By 15th week of gestation corneal
endothelial cells extend into the angle
recess and meets with iris epithelium
By 3rd month angle recess deepens and
forms iridocorneal angle
In 7th week – the angle of the anterior
chamber is occupied by the mesenchymal
cells of neural crest(1st wave) origin- forms
trabecular meshwork
Schlemm canal develops from small plexus
of venous canaliculi of endodermal origin
and forms uveoscleral outflow/tract.
Schlemm canal appears in 4th month of
Gestation
Completion of Ant.Chamber Angle
formation~8th month of Gestation.
42. Trabecular meshwork
The anterior chamber angle continuous to recede until 6-12
month after birth when it become adult type appearance.
Anterior chamber depth is 2.3-2.7 mm at birth (adult-3mm
range 2.5-4.4)
In the final week gestation the
trabecular meshwork undergoes
fenestration and communicates with
anterior chamber
Congenital glaucoma may occur as a
result of defect in terminal
differentiation of trabecular tissue
leading to excessive formation of
meshwork collegen preventing
formation of iridocorneal angle
43. Ciliary body and iris
By 3rd week gestation there is extension
of 2 layers of neuroectoderm from the
edge of optic cup
Its has outer pigmented epithelium(PE)
and inner non pigmented
epithelium(NPE)
Distal part of advancing neuroectoderm
becomes an iris
Proximal part of neuroectoderm
extension becomes the ciliary body
44. Ciliary body(CB)-ctn..
CB begins to appear at 9th week of gestation
Cellular proliferation of proximal 2 layers of
neuroectoderm forms longitudinal indentation
of outer pigmented epithelium
By 12 weeks Inner non pigmented layer forms
radial fold(75) and become 70-75 ciliary
processes(fully form in 4th month)
At 10 week mesenchymal cells get condensed
at its anterior surface to form the stroma of
ciliary body
At 12 weeks there is Myofillament proliferation
of mesenchyme and forms smooth muscles of
ciliary body by 5th month
Ciliary muscle continues to develop for at least
1year after birth.
45. Ciliary body
By 4th month ciliary body is
functional and secrets
aqueous humour which fills
up anterior and posterior
chamber
Ciliary epithelium synthesis
collagen fibers which
becomes suspensory
ligament/zonules of lens
Zonules~Begin to develop
at 10th week and by 5th
month reach Lens
46. Development of iris-3rd month
Developed from 2 layers;
1. Mesenchyme-anterior stroma
2.Neuroectoderm of optic cup–
- iris pigment epithelium
-sphinchte and dilater muscles
Iris begins to develop by condensation of
2nd wave mezenchymal to form Pupillary
membrane
47. Iris epithelium-end of 3rd month
Pupillary membrane formed by
condensation 2nd wave
mesenchymal cell in early 3rd month
2 layers of neuroectoderm from the
edge of optic cup extend to the
posterior surface of pupillary
membrane.
Three structures(PE,NPE and
pupillary membrane) ultimately
fuses to become an iris
Pupillary
membrane
48. Iris- 3rd month
At 3rd month Cells of anterior epithelium
layer differentiates into myofobrills and
forms sphincter and dilator muscles of an
iris
Pupillary Membrane(PM)-cells of PM
differentiates into fibroblast like cell and
secrets collegen fibrills & extracelluler
matrix which is incorporated with PE to
form the anterior stroma of an iris
Iris fully developed by 5th month
pigmentation of posterior epithelial
cell occurs begins at the pupillary
margin at midterm , by 7th month
iris is fully pigmented
49. Iris and pupil-8th month gestation
Pupillary membrane begins to
degenerate at about 8th
months of gestation
Opening in the central part of
iris forms the pupil
Iris stroma and dilator muscle
is still immature at birth-pupil
appears miotic at birth
Dilator Pupillae poorly
developed & doe not reach
adult proportions untill about
5th year of age.
50. Iris anomalies
Can be Associated with syndromic presentation like trisomy 13, klinefelter,turner,
CHARGE association(ocular coloboma,heart defects, choanal atresia, mental
retardation, genitourinary and ear anomalies)
1.Hypoplasia/absence of an iris
Inadequate inductive interactive between optic cup,
surface ectoderm and neural crest cell due to Defect in
PAX6 genes
Occurs as sporadic or autosomal dominant
2.Persistant pupillary membrane
Most common congenital iris anomalies
Failure to atrophy pupillary membrane
3.Iris Coloboma
Failure of embryonic fissure to close in 6th or 7th week of
gestation
Pupil appears like inverted tear drop usually at the
inferonasal quadrant
Can be associated wit coloboma of choroid, retina, ciliary
body and optic nerve
51. Iris anomalies…
7.Conginatal mydriasis
Malfoamation of iris sphincter muscle
Sphicter Muscle of the Pupil is fully differentiated by 6th
month of gestation
4.polycoria -Accessory iris opening
Associated with Axenfeld-Reiger Syndrome ( autosomal
dominant disorder) due to mutation of PAX and FOXC1
gene
Present with ,malformation of face, teeth, skeletal system
5.Corectopia-Displacement of pupil
Associated with sector iris hypoplasia or colobomatous
lession or lens subluxation(ectopia lentis et pupillae)
6.microcoria-congenital miosis
Occurs due to malformation of dilator pupillae muscle
Can be associated with microcornea,lens subluxation, iris
atrophy and glaucoma
52. Posterior chamber
Develops as a slit in the mesenchyme posterior to
the developing iris and anterior to the developing
lens
Anterior and posterior communicates when the
pupillary membrane disappears and the pupil is
formed
Aqueous humor fills these two chamber
54. Retina-originates from Neuroectoderm
Neurosensory retina-
originates from the inner layer
ofneuroectodermal cell of optic
cup
Retinal pigment epithelium-
Originates from the outer
neuroectodermal cell of an optic
cup
55. Neurosensory layer-1st month
Anterior 1/5th – forms the posterior
surface of developing ciliary and iris
Posterior 4/5th forms the primordial
sensory retina
Single layer epithelium with ext &int
basement mem
Proliferates to forms two 2 distinct
zones by 4th-5th week(35th day)
Outer 2/3rd –primitive nuclear zone has
rows of nucleated cells which will
forms neural cells-Outer primitive
zone or Nuclear zone or germinal epi
Inner 1/3rd- Inner marginal zone has
cells devoid of nucleus which will form
nerve fiber layers
56. Neurosensory(NSR) retina
NSR begins to develop from outer primitive nuclear
zone(PNZ) with 8-9 row of nuclei
Mitotic Cellular proliferation of PNZ forms 2 distinctive
layers by 6th-7th wks
1. Outer neuroblastic layer(forms photoreceptors) forms rods
&cones,biolar cells &horizontal cells
2. Inner neuroblastic layer(Ganglion cell layers) forms ganglion
cells,muller’s cell &amacrine cells
3. Two neuroblastic layer are seperated by transient nerve fiber
layer of Chievitz which become inner plexiform layer by 10.5th
week gestation
57. NSR formation…ctn…
Differentiation of outer neuroblastic layers occurs(ONL)by
10th-12th week & form Bipolar & Horizontal cells &
photoreceptor cells (rods and cones)
Differentiation Inner neuroblastic layers and form
ganglion cell layer &layer of amacrine &muller cells(first
inner nuclear layer)
Axons from ganglion cell develops at 10th-12th week and
form primitive nerve fiber layers
A new intermediate nuclear layer,inner nuclear layer
identified by 4th month in posterior pole retina contains
biolar &horizontal cells also
Thus differentiation of Retinal Layer starts during 6th week of
gestation & by 5th&1/2 month of gestation all layer i.e 10 layer of
adult Retina are recognizable
58.
59. Cellular proliferation and melanogenesis of outer wall of
optic cup begins by 6th week and forms retinal pigment
epithelium(RPE)
Initially RPE is mitotically active pseudostratified
columnar ciliated epithelium cilia disappear as
melanogenesis commence & mitotic activity ceases by
birth
Mature RPE~hexagonal shape,homogenous in size &
simple Cuboidal eithelium
By 15 week gestation all cells types , synapses and
intercellular junction of neurosensory retina are formed
Fovea is formed by thinning of ganglion and inner
nucleated layer by 24 weeks (7th month) of gestation
Outer 4 layer of retina get nutrition from Choroidal vessels
& Inner 6 layer from Central Retinal Artery
60. Some imp landmark in Retina Development
Synaptogenesis~in Cone pedical occur at app.4th month &
in Rod sherules at app.5th month
Photoreceptor outer segment formation commence
arround 5th month
Horizontal cell become distinguishable arround 5th month
Microglia (resident tissue microhages) invade retina via
retinal vasculature by 4th month & subretinal space by 10th
week onward
Terminal expansion of muller cells beneath inner limiting
membrane mature arround 4.5 months
Macular area~begin to differentiate at 11th wk of
gestation, development delayed upto 8th month of
gestation ,differentiate upto 4th-6th month after birth.
61. Optic nerve
Develops from optic
stalk(connection between
optic vesicle and forebrain)
Initially optic stalk has two
layers
1. Inner neuroectodermal cells
layer
2. Outer undifferentiated
neural crest cells layer
62. Optic nerve formation
Late in 6th week, cells of inner layer of optic
nerve degenerates and become vacuolated
Nerve fibers (axons) from the ganglion cells
migrates through the vacuolated space of
optic stalk
By 33 weeks it establishes an adult type optic
nerve of app.1.2 million of axons
Few cells of inner layer differentiated into glial
cell which forms lamina cribosa by 8th week.
Myelination~begin from chiasma at 7th
month,proceeds distally & reach Lamina
Cribrosa just before birth and stop there
In some cases myelination extend upto
arroundOptic disc ~Cong. Opaque nerve fibre
Outer neural crest cells differentiates into (1)pia, (2)arachnoid and
(3)dura matter which form optic nerve sheath by 4th month
63. Cong anomalies of Retina & Optic nerve
1. Congenital Retinoschisis~x-linked recessive,
associated with stellate pattern at fovea & occasional
vitreous haemorrhage
2. Norries’s disease~x-linked recessive, retrolental mass
with elongated ciliary rocesses with retinal
detachment.Associated with mental retardation
3. Incontinentia pigmenti~ ass. with proliferative retinal
vascular abnormalities,total retinal
detachment,cataract,RPE changes
4. Familial exudative vitreoretinoathy
5. Congenital retinal folds
64. 6.Morning glory disc anomaly
Appears as funnel shaped excavation of the
posterior fundus that incorporates the disc.
Occurs due to abnormal closure of embryonic
fissure(EF)
Disc has central excavation surrounded by elevated
rim of pink neuroglial tissue with vessel emerging
radially as spokes in all directions
Sometimes remnant of sheath of hyloid vessel form
Bermeister papilla
7.Coloboma of optic nerve.
May occurs as a part of chorioretinal coloboma or
solitary abnormality d/t EF fail to close
Can be associated with systemic abnormalities-
CHARGE association~coloboma,heart disease
atresia choanae,retarded gwth,genital hyolasia,ear
anomalies with or without deafness
65. Formation of vitreous
Develops between lens and optic cup
Mostly derived from mesoderm with minimal
contribution from ectoderm
Formation of vitreous occurs in three stages ;
❶ Primary vitreous~ Mixed ectodermal &
mesenchymal origin, develop between 3rd-9th wk of
gestation
❷Secondary vitreous~Neuroectodermal in origin,
begin to develop arround 9th wk
❸Tertiary vitreous ~Neuroectodermal in origin,
develop during 4th month gestation
66. Primary vitreous-1st month of gestation
Network of delicate cytoplasmic
process which occupy the space
between lens vesicle and inner
layer of optic cup
Surface ectodermal element
surround lens during invagination
thought to contribute primary
vitreous so mixed origin
It is composed of fibrils (ectoderm)
and mesenchymal cells(mesoderm)
which constitutes primary vitreous
Supplied by hyaloid vessels and its
branches so it is vascular
67. Secondary vitreous- 2nd month of gestation onward
(arround 9th wk) By 2nd month the hyaloid system regresses
and primary vitreous cell differentiates into
hyalocytes which synthesis type 2 collagen
and hyaluronic acid which constitutes
secondary vitreous
2nd vitreous is avascular gel like substances
occupying the space between primary
vitreous and retina
By 5th -6th month primary vitreous and
Hyaloid vessels undergoes atrophy,
regress from perihery to centre &
regration stop at optic disk leaving
central retinal artery
Atrophied hyaloid vessels become hyaloid
cannal which remain throughout the life
as Cloquet canal, from optic nerve head
to posterior surface of lens.
Primary vitreous
68. Tertiary vitreous-4th month
Developed from Neuroectoderm in the ciliary region
during 4th month of gestation
Represented byVitreous base & ciliary zonules
Collagen fibrils synthesized by
ciliary epithelium becomes more
condensed and extends to the
lens equator and become zonular
fiber of lens which constitutes
the tertiary vitreous
Primary & secondary vitreous
remain in contact with posterior
lens casule as hyaloidcasular
ligaments
69. Persistent hyperplastic primary vitreous(PHPV) or
persistent foetal vasculature(PFV)
Presents as leukocoria-white pupillary reflex
Its occurs due to failure of primary vitreous
and hyaloid vessels to regress
Severity range from pupillary strands &
mittendrof’s dot to dense retrolenticular
membrane &/or retinal detachment
Two tyes 1)Anterior PFV 2)Posterior PFV
Prognosis of Posterior PFV is poor
Insufficient level ofVitreous Endostatin
may be pathogenesis
Normal retinal development required for
proper vitreous biosynthesis(some str.
Component synthesized by Muller Cells)
70. Choroid
Vascular endothelium and the haemopoietic cells of
choroid are derived from endoderm
Choroidal stroma ( vascular pericytes, smooth muscles,
melanocytes and collagenous components) of choroid
are derived from inner vascular layer of mesenchyme
that surround optic cup(Neural Crest)
71. Choroid..cntn
Differentiation of neural crest
cells form choroidal stroma by
the end of 3rd month
gestation
Endothelium line blood vessels appears in the
choroid stroma and forms choriocapillary
By 4the week Choriocapillary begins to
differentiate,6th wk completely form and by 2nd
month it anastomosis with short ciliary artery
By 5th month all layers of Choroid now visible and
melanocyte appear in it’s external portion
By 8th month final arterial circulation of choroid is
established after anastomosis with vessels of
ciliary body and iris
72. Sclera
Sclera is mostly ectodermal (neural crest) in origin,
however posterior region are mesoderm in origin
Sclera begins to develop by condensation
of mesenchymal cells around the anterior
rim of optic cup
Mesenchymal cells proliferates and
deposits glycosaminoglycans, collagen
and elastin fibrils and forms stroma of
sclera
Process Starts at Limbal Equatorial region
(future site of extraocular muscle
insertion) arround 7th wk of gestation
By 5th month sclera is relatively well or
complete formed
73. Vascular system of eye
Arterial wall has three layers;
1. Tunica adventitia(connective tissue)
2. Tunica media(smooth muscle layer)
3. Tunica intima( endothelium)
Tunica adventitia and tunica media of ocular vessels are
derived from neural crest cells(ectoderm)
Tunica intima is derived from endoderm
74. Primitive orbital vessels
During early embryonic life untill 8th month, the developing
ocular structure is nourished by three transient vessels
originating from internal carotid artery;
A.Ventral ophthalmic artery
B. Dorsal ophthalmic artery
F. Stapedial artery
Ventral artery later atrophy and only a portion remain as long
posterior nasal ciliary artery
Dorsal ophthalmic artery become definitive ophthalmic artery
Stapedial artery becomes Middle meningeal artery
75. Primitive ocular vessels
Embryonic intraocular vasculature system has two
components;
1. Anterior system- supplies anterior segment
formed in iris and pupillary membrane
formed by the branches of ophthalmic artery- seven anterior
ciliary artery and two long posterior ciliary artery
2.Posterior system- supplies posterior segment
formed within the vitreous
formed by hyaloid vascular system
76. Anterior artery system
Anterior artery system is formed by two
long posterior,10-20 short ciliary artery
and 7 anterior ciliary artery which are
the branches of dorsal opthalmic artery
Anastomosis of long posterior ciliary
arteries and anterior ciliary arteries
forms major arterial circle at the root of
iris
Vascular twigs from major arterial cicle
and annular vessels forms the pupillary
arcade
With the disappearance of pupillary
membrane pupillary arcade remain
peripherally as minor artery circle which
supply iris
Posterior
ciliary artery
Anterior
ciliary artery
77. Posterior arterial system
Hyaloid artery nourishes the developing eye globe until the
8th month of gestation
Hyaloid artery is the branch of primitive dorsal ophthalmic
artery emerges in 5th week of gestation
Later the Hyaloid artery regresses and become central
retinal artery
78. Hyaloid system….
As the optic vesicle develops there
is incomplete folds in its inferior
portion of cup and stalk called
embryonic fissure
Embryonic fissure allows hyaloid
system to be incorporated within
the eye.
In 5th week Hyaloid artery enters
the embryonic fissure of optic
stalk.
With the fusion of fissure the
hyaloid system are enclosed
within the eye
79. Hyaloid system
Branches of the hyaloid artery supplies developing lens,
vitreous, optic nerve
Anastomosis of branches of hyaloid artery forms 3
arterial arcades calledTunica vasculosa Lentis by 9th wk
1.Anterior vascular capsule
2.Capsulopupillary portion
3.Posterior vascular capsule
Valsa hyaloida propria(small
capillary branches)
Hyaloid artery
80. Retinal circulation
By 4th month the hyaloid artery bud of to from central
retinal artery
Hyaloid artery system begin to atrophy and regresses
in 3rd month of gestation
Retinal artery vascularizes the retina by giving four
branches two for temporal and two for nasal side,
supplies inner six layer of retina
Nasal retina completes vascularization prior to
temporal retina in 7th month of gestation
By 9th month all retinal part are vascularized except
for portion of peripherals temporal retina
Retina also well developed nasal side before temporal
81. Retinal circulation
Atrophied hyaloid system
Retinal vessels buds from
hyaloid artery and
vascularizes retina
Vascularization reaches
nasal ora serrata by 7th
month and temporal
periphery by 9th month
82. Retinopathy of prematurity
ROP associated with systemic abnomalities as anaemia,BPD,
cardiac defect,NE,IVH,cerebral palsy &neurodevelomental delay
Premature baby has incomplete
vascularization of retina
Hyperoxia(supplementary oxygenation)
causes vasoconstriction
Vasoconstriction causes ischemia in the
incompletely developed retinal
periphery
Ischemia trigger abnormal vessel
formation called neovascularization-
retinopathy of prematurity
ROP has five stages &VEGF has
important role in pathogenesis
83. Accessory ocular structures
EYELIDS~ start at 6th- 7th wk of IUL,margin of two lids
unite with flimsy tissueby 9th wk & separate 5th month
of IUL(uto 26th-28th wk)
Both eyelid formed by reduplication of surface ectoderm
1.Lower eyelid-Formed from maxillary process &
connective tissue & tarsal plate from visceral
mesoderm of Maxillary process
2.Upper eyelid-Formed from lateral and medial aspect
of frontonasal & connective tissue & tarsal late from
periocular mesodem derived from neural crest
Skin of eyelids and it’s derivatives cilia,cojunctival &
Tarsal Gland-from Ectodermal cell from lid margin.
84.
85. Continue……….
Conjunctiva~ from surface ectoderm
Lacrimal apparatus~
1.Lacrimal Gland-from 8 cuneiform eithelial bud from
superolateral side of conjunctival sac, by end of 2nd
month.At term still undeveloped & tear not formed
2.Lacrimal Sac,Nasolacrimal duct and canaliculi-
developed from ectoderm of nasolacrimal groove
Nsolacrimal duct becomes completely patent only
after birth
Extraocular Muscles~are some of few periocular
tissues that are not neural crest origin,differentiated
from prechordal mesenchyme,start in 5th-6th wk
(LR,SR,LPS-5th wk;SO,MR-6th wk & then IO,IR)
86. Conti…..
Orbit~derived above from mesenchyme encircles
optic vesicle,below & laterally from maxillary
processes,medially by frontonasal process &
behind by pre-and orbitoshenoid.
Orbit Bone Formed by membraneous ossification
Bone differentiated during 3rd month
InitiallyOptic Axis direct laterally, later they
directed anteriorly
At Birth Orbit is hemispherical & more divergent
(50 degree) as compare to adult-45 degree
Eyeball reachesAdult Size by 3 year of age
Orbit alteration in shape & grows until Puberty
87. Congenital anomalies of Eyelids
1. Eicanthal fold
2. Telecanthus
3. Epibleharon
4. Blepharophimosis
5. Eurybleharon
6. Coloboma of lid~Upper lid at middle & lateral third
seen in Goldhar’s Syndrome, Lower lid seen in
Teacher collins Syndrome with hypolasia of lower lid
7. Ankylobleharon
8. Cryptophthalmos~failure of sepration of lid during 4th
to 6th wk of IULthus lids fail to develop & skin passes
from eyeball to cheek hiding eyeball
88. Congenital anamolies of conjunctiva
1. Congenital cystic lesions~ rare,include congenital
corneoscleral cyst & cystic form of epibulbar dermoid
2. Dermoid ~common congenital tumour,occur at
limbus,solid white masses,firmly fix to cornea
3. Lipodemoid (epibulbar dermoid)~at limbus 0r outer
canthus,movable subconjuntival mass
4. Naevi or Congenital moles~common pigmented
lesions,mostly near limbus,appears in early childhood
& may increase in size at puberty or during
pregnancy
89. Congenital anomalies of lacrimal
apparatus
1. Congenital NLD block~in 80-90% residual membrane
spontaneously dissolve within 2-4 month after birth
2. Congenital lacrimal Fistula (lacrimal anlage duct)~
fistula open on skin below and medial to lower
punctum , may associated with congenital NLD block
3. Punctal Atresia~Imperforated punctum,
presumed location of punctum identified as a
shallow dimple at appropriate site
90. Human eye at birth and after birth
Newborn are hypermetropic by 2-3D because of
less axial length of eye( at birth 16.5mm, adult
24mm,70% of adult attained by 7-8 years)
Corneal diameter is 10mm at birth and 11.7mm in
adults is attained by 2 years of age
Radius of corneal curvature is 6.6-7.4 mm at birth
and 7.4-8.4 in adults
Retina fully differentiated at birth except Macula,
differentiate in first 4 month with foveal reflex
General picture of fundus as adult after 6th month
91. …………continue
Newborn has miotic pupil because dilator pipillae muscle
is not well form at birth.Reach adult proportion~at
approximately 5th year age
Lens Spherical at birth
Orbit is more divergent (50) as compared to adult (45)
Anterior chamber is shallow and angle is narrow
Visual development
Pupillary light reflux-present after 31 week of gestation
Blink reflex to light- several days after birth
6 weeks-maintain eye contact and react with facial expression
2-3months –preferential to bright objects
Conjugate fixation~become established by 6th month
92.
93. References
1.Anatomy and Physiology of eye-2nd edition,Dr.A K
Khurana
2.Ophthalmology,third edition,Dr.A K Khurana
3.Langman’s Medical Embryology,11th edition
4.Parsons Diseases of eye,22nd edition
5.Yanhoff’s Ophthalmology,4th edition
6.Essential of Embryology and Birth Defect,7th edition
7.Internate Resources
