Morfology and embryology

Odilo Redon

 Shape of 4-sided pyramid falled backside
 Bony margins
 aditus x apex
 10 openings
 m. orbitalis Mülleri
– smooth muscle in fissura orbitalis inferior
 content: eye ball, muscles, adipose tissue and accessory organs

Surrounding structures:
 medially: cellulae ethmoidales (behind thin lamina orbitalis o.e.)
 caudally: sinus maxillaris
 cranially: fossa cerebri anterior
 dorsally: sinus cavernosus + fossa pterygopalatina

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 tunica fibrosa
(externa)
 tunica vasculosa
(media)
 tunica interna
(nervosa)
 Vitreous body + lens cristallina

 polus anterior, posterior
 equator x meriadiani
 axis bulbi externus, internus
 axis opticus (= „linea visus“)

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 Thick tissue (= reticulum trabeculare), colagenous fibers, fibroblasts, basic substance
 lamina episcleralis, substantia propria, lamina fusca
 lamina cribrosa (entrance of n. II.)
 5/6 of surface, ø 2,2 cm
 sinus venosus sclerae (canalis Schlemmi s. Lauthi )
 sulcus sclerae – sclerocorneal junction = limbus corneae
(angulus sclerocornealis)

 Totally translucent, w/o vessels
 limbus, vertex
 5 layers
– epithelium anterius cornae (multi l. cuboid)
– lamina limitans anterior (
Bowmann membrane)
– substantia propria corneae
– lamina limitans posterior (
Descement membrane)
– epithelium posterius corneae („endotelium“)
 11 x 12 mm – fyziological astigmatismus

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 lamina suprachoroidea (= lamina fusca sclerae)
 spatium perichoroideum
 lamina vasculosa (choroideal stroma)
– Big vessels, tissue, smooth muscle cells, nerves
 lamina choroidocapillaris
– capillaries
 lamina basalis = Bruch membrane
– BM pigment epitelium and capillaries + tissue

 Shape of annulus, section of triangle
 processus + plicae ciliares
 orbiculus (outer part), corona (inner part)
 smooth musculus ciliaris
– fibrae meridionales, radiales, circulares, longitudinales

 stroma
– m. ciliaris : parasympaticus
 akomodation
 look close
(look remote maintains plasticity of uvea)
– Capillaries and nerves supplying muscle
 Epitelial cover – production of humor aquosus
– BL – continuation of Bruchs membrane
– pigment epitelium – (from pigment epitelium of retina)
– Cilliary canal
– Non pigmented epithelium (from sensory epithelium of retina)
– BL
– fibrae zonulares – fixate lens

 Shape of annulus, flat
 Function of shutter
 margo ciliaris (outer), m. pupillaris (inner)
 pupilla (= pupil)
 anulus iridis major + minor (contain circulus arteriosus iridis major + minor)
 m. sphincter pupillae ( parasymp .) – miosis (circular)
 m. dilatator pupillae ( symp.
) – mydriasis (fanwise)

 plicae iridis, stroma iridis
 Anterior pole
– Does not have epithelial lining ( stratum limitans anterius)
– fibroblasts and melanocytes (color)
– plica radians = serrated line – remnant of membrana pupillaris Wachendorfi
 Posterior pole
– Two layers of pigment epithelium
– Inner pigment
– Outer myoepitelial
• m. sphincter pupillae
• m. dilatator pupillae

 polus anterior, posterior
 axis, equator, radii (sutures in Y shape and reversed
Y)
 capsula lentis
 substantia lentis – cortex, nucleus
 zonula ciliaris Zinni
– fibrae zonulares
– spatia zonularia
Gray cataracta - prosthesis

 transparent biconvex w/o vessels
 capsula – similar to basal lamina
 Lens epithelium – single layer cuboid
– Only on anterior side of lens
 Lens matter
– cortical – contains elongated cells (fibers) with organels and nucleus
– nuclear – cellular fibers w/o organles and nucleus
– Cells contain specific proteins (filensin, crystallins)

 Focusing on close distance
– Contraction of m. ciliaris
– fibrae zonulares relaxing
– Lens forms ball
– Together with contraction of m. sphincter pupillae (= miosis )
 Focusing on remote distance
– Tonus of vessels maintains fibrae zonulares extended
– Lens is flattened
– Contraction of m. dilatator pupillae (= mydriasis )

 membrana, stroma, humor vitreus
 Composed of 99% water
 Hyaluronic acid, kolagen fibers
 cells – hyalocytes – only during development !
 Does not regenerate ! – in case of injury it flows out – exchanged by chamber fluid
 canalis hyaloideus Cloqueti – remnant of fetal arteria hylaloidea
 fossa hyaloidea
 Maintains inner eyeball pressure, pushes retina

 Produced by ciliary body
 Reabsorbed in angulus iridocornealis
 0,2-0,3 ml translucent, watery fluid
 Daily produced cca 3 ml
 composition: 0,7-1,2 % NaCl, traces of urea and glucose (0,1%), no proteins
 Serves as lymph
 Intraocular pressure 14-17 mmHg

Intraocular pressure
 pressure on retina
 glaucoma (= glaukom)

 Vitreal chamber (camera postrema s. vitrea)
– Between ciliary body, lens and retina
– Contains vitreous body
– spatium retrozonulare
 posterior chamber (camera posterior)
– Between iris, lens and ciliary body
– Contains and produces humor aquosus
 Anterior chamber (camera anterior)
– Between cornea and iris
– angulus iridocornealis
– Contains and reabsorps humor aquosus

 At the sclerocorneal junction
 Trabecular frame of the back side = spatia anguli i.c. = Fontana spaces
 Not connected with
Schlemm canal
 Resorption of humor aquosus
 Maintenance of intraocular pressure
 !!! No parasympaticolytics in glaucoma !!!

OCT
Optical coherent tomograp h measurement of light reflection

 pars caeca
– pars iridica
– pars ciliaris
 ora serrata
 pars optica – 11 layers
– pigment part
– Sensory part

 stratum pigmentosum
 Single layer cuboid epithelium
 cells ( pigmentocytus ) connected by tight junction
 Apical part contains melanin granules
 Surrounds external segments of sensory cells
 interfotoreceptor matrix
Cell nutrition, fotopigment rejuvenation, degradation of membranous discs

 Light recepting neurons
– Rods and cones
 Conduction neurons
– Bipolar and ganglionic cells
 Association neurons
– Horizontal and amacrine cells
 Supportive cells (glia)
– Müllers cells

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– No light perceiving elements
 excavatio disci

– Sharpest vision
– fovea centralis (100.000 cones)
 foveola (2500 cones)

 rod = bacillum retinae
 synaptic disc ( discus membranaceus )
 axon
 nucleus
 Inner segment
– GA, ER, MIT; synthesis of ATP and rhodopsin
 Outer segment ( segmentum externum )
– Membranous discs with fotopigment
– migrate externally till separation black-white vision

 rod = conus retinae
 synaptic pod ( pes terminalis )
 fotopigment is iodopsin
 External segment
– Membranous discs with fotopigment
• Communicate with around
 Color vision
– three types of rods – according to wave length
– „blue“ – 420 nm – type S
– „green“ – 535 nm – type M
– „red“ – 565 nm – type L

 Bipolar cells ( Neuron bipolare )
– Staminate bipolare cells ( n.b. bacillotopicum )
– Cony bipolar cells ( n.b. conotopicum )
• Dwarfy cells ( n.b.c. nanum ) x diffuse cells ( n.b.c. diffusum )
– contact with ganglionic cells
 Ganglionic cells ( N. ganglionare multipolare)
– Diffuse type ( n.g.m. umbelliforme ) – connects more bipolar cells
– Dwarfy type ( n.g.m. nanum ) – connects to dwarfy bipolar cell
– Their axons form nervus opticus

Have only axonal extensions – both direction
 Horizontal cells ( N. horizontale )
– Connection with rods and cones
 Amacrine cells ( N. amacrinum )
– Connection with bipolar and ganglionic cells
Modification and synchro of signal

 Müllers cells (Gliocytus radialis)
– macroglia
– processus radiales
– Have their own BL = membrana limitans interna
– zonulae adherentes with rods and cones
• = membrana limitans externa

 celkem 11 vrstev



 stratum pigmentosum (1.)
 stratum nervosum (2.-10.)
– stratum segmentorum externorum et internorum(2.)
– stratum limitans externum (3.)
– stratum nucleare externum (4.)
– stratum plexiforme externum (5.)
– stratum nucleare internum (6.)
– stratum plexiforme internum (7.)
– stratum ganglionicum (8.)
– stratum neurofibrarum (9.)
– stratum limitans internum (10.)

 ora serrata – termination of sensory epithelium
 pars optica – 10 layers
– discus n. optici /formerly papilla / (= blind spot) – place of nerve separation
• No light detecting elements
• excavatio disci
– macula lutea (= yellow spot) – higher layers bent to the side, sharpest vision
• fovea centralis (100.000 cones)
– only cones
– Higher layers bent side
– Sharpest vision
 foveola (2500 cones)

OCT
Optical coherent tomograph measurement of light reflextion

OCT

OCT

a. carotis interna
 a. ophthalmica

 aa. ciliares posteriores breves
 choroid
 aa. ciliares posteriores longae (2

4)
 corpus ciliare + iris
 aa. musculares
 aa. ciliares ant., aa. episclerales , aa. conjuctivales lat.
 a. centralis retinae
 retina
 a. lacrimalis
 aa. palpebrales lat.
 aa. palpebrales med.
 aa. conjuctivales med.

a. centralis retinae
 arterioles
 a. temporalis sup.+ inf.
 a. nasalis sup.+ inf.
 a. macularis sup.+ inf.
(+ media)
Veins corresponding to arteries, often crossing

 appearance: 10-33 %
 Branch from a. ciliaris posterior brevis
 Enters via discus n.II independently on a. centralis retinae
 Acessory arterial supply of macula lutea from choroid circuit
 Only source of blood for retina during closure of a. centralis retinae
 90 % temporally - 10 % nasally
 closure of a. cilioretinalis → central scotoma
 Closure of a. centralis retinae → spared central vision of macula lutea

 vv. episclerales
 vv. ciliares ant.
 vv. sclerales
 sinus venosus sclerae Schlemmi s. Lauthi
 vv. vorticosae (4 in quadrants of eye ball)
 v. centralis retinae
 v. ophthalmica sup.
 sinus cavernosus
 v. ophthalmica inf.
 plexus pterygoideus
 v. angularis
 v. facialis
 v. jugularis int.
! Danger of inflammation spreading !

 n. opticus
– sensory
– pars intraocularis, canalis, intracranialis
– vagina interna, externa
 n. ophthalmicus
 nn. ciliares longi – sensory
 n. lacrimalis, n. frontalis, n. nasociliaris – for surrounding
 nn. ciliares breves
 ganglion ciliare autonomous
(sympaticus does not connect, parasympaticus yes)
 n.III., n. IV., n.VI
– motoric

 Exvagination of diencephalon (thalamus opticus)
 Axons separated by endoneurium
 On the surface are analogs of cerebral coverings
 Inside nervus running a. et v. centralis retinea

Projection → Ascending → Sensory path
4 - neuronal, partially crossed
•
•
•
• neuron: rods and cones of retina neuron: bipolar cells of retina neuron: ganglionic cells of retina
 n. II
 chiasma opticum
 corpus geniculatum laterale neuron: cells of corpus geniculatum laterale
 tractus geniculocorticalis (= radiatio optica
Gratioleti)
 lobus occipitalis, area 17 (around fissura calcarina)

Visual path sides from 3rd neuron


 into hypothalamus (nucleus suprachiasmaticus) – transfers optical signals to highest vegetative centers ( sight of food = salivation )
Tracts of pupillary reflex
– via area pretectalis
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 to nucleus accessorius dorsalis n. III / Edinger-Westphal / - parasympatic path vith n. III
 ganglion ciliare
 nn. ciliares breves
 m. ciliaris et m. sphincter pupillae / miosis + acommodation / into retikular formation
 tractus reticulospinalis
 centrum ciliospinale /Budge/ C8-Th1
 sympathetic path in truncus symphaticus
 ganglion cervicale superius
 plexus caroticus internus et ophtalmicus
 nn. ciliares breves
 m. dilatator pupillae / mydriasis /
Path for convergence
 nucleus interstitialis /Cajal/
 fasciculus longitudinalis medialis
 nuclei of all eyeball moving nerves
 Tectal visual circuit - tractus tectospinalis (direction of eyeball synchro, head and neck towards visual inputs and for coordination of whole body movements)

 Fibrous apparatus = Apparatus ligamentosus
 Lids = Palpebrae
 Conjunctiva = Conjunctiva
 Lacrimal apparatus = Apparatus lacrimalis
 Muscular apparatus = Apparatus muscularis
 eyebrow = Supercilium

 periorbita
 vagina bulbi (= capsula Tenoni)
– lig. suspensorium bulbi
 spatium episclerale
 corpus adiposum orbitae
 fasciae musculares

 t.c.bulbi et palpebrarum
 fornix superior, inferior
 Continuation of corneal epithelium, continues from behind to eyelid, covers ventral side of eyeball
 Multi layer cylindrical epithelium
 Contains cup cells
 Lacrimal film ( irroratio lacrimarum )
 glanduale conjuctivales Wolfringi
 caruncula lacrimalis

 palpebra superior, inferior
 tarsus superior (10 mm), inferior (5 mm)
 lig. palpebrale med. (2 lines) + lat.
 facies ant.+post., rima palpebrarum, commissura palp. med.+lat., limbus ant.+ post.
 angulus oculi med.+ lat.
 m. tarsalis sup.(Mülleri) + inf. – smooth muscles
 pars palpebralis m. orbicularis oculi n. VII
 m. levator palpebrae superioris n. III
 eyelashes = cilia

 External skin part
– Multi layered flat cuboid epithelium w exfoliation
– gll. sebaceae
Zeissi
• Ceruminous glands hordeolum
– eyelashes + gl. ciliares
Molli
• Apocrine glands
 m. orbicularis oculi
 Tarsal plate
– fibroelastic
– gll. tarsales Meibomi
• Ceruminous glands chalazion
 Inner conjunctive part
– Epithelial transition - sulcus

 glandula lacrimalis
– pars orbitalis + palpebralis
– 12 – 15 individual ductuli excretorii
 glandulae lacrimales accessoriae Krausei
 rivus lacrimalis
 lacus, papilla, caruncula lacrimalis
 puctum, canaliculus lacrimalis
 saccus lacrimalis
 ductus nasolacrimalis (plica lacrimalis Hasneri )
 meatus nasi inf.
 In drainage lacrimal pathways more small villi

Glandula lacrimalis
 tubuloacinous serous glands with myoepitelial cells

 mm. recti bulbi: sup., inf., med., lat. (VI.)
 mm. obliqui bulbi: inf., sup.(IV.)
– /fovea trochlearis, spina trochlearis, trochlea, vagina m.o.b.s./
 m. levator palpebrae sup. (pars spf.+prof.)
 n. III – ostatních 5 svalů
 hladké svaly: m. orbitalis Mülleri , m. tarsalis sup. Mülleri + inf.

Movements around axes = duction
 Around vertical axis
– adduction (inside)
– abduction (outside)
 Around horizontal axis
– elevation (sursumduction; supraduction): up
– depression (deorsumduction; infraduction): down
 Around sagittal axis (ventrodorsal) :
– intorsion (incykloduction): flapping inside
– extorsion (excykloduction): flapping outside

Movements paired (together with both eyeballs)
 Same directed conjugated paired movements = version
(conjugated movements)
– dextro version (right) + sinistroversion (left)
– supraversion (sursumverza) + infra/deorsumverza (up + down)
– dextro/sinistroelevation + dextro/sinistrodepression (up/down and to sides)
– dextro/sinistrocycloversion (rotation right/left)
 Counter directed non conjugated paired movements = vergence
(non conjugated movements)
– convergence = inside direction of axes from both eyeballs
– divergence = outside direction of axes from both eyeballs
 strabismus = heterotropie = cross eye:
– one eye is persistently rotated inward or outward

Eyeball movements

 esotropie (s. convergens)
 exotropie (s. divergens)
 hypertropie (s. sursumvergens)
 hypotropie (s. deosumvergens)

 neuroectoderm of ventral forebrain
 Surface ectoderm of head
 In between mesenchyme
 Cells of neural crest

 Development since 4th week
 Origin of eye rims in ventral forebrain
 Deepens into eye sacs
 Formation of eye stalk
 Induction of ectoderm = thickening
 Origin of eye placode

 Invagination of eye placode
 Origin of hollow lentiform sac w/o connection with surface
 Eye sacs invaginate = eye cup
 Invagination of stalk and cup with entering of vascular mesenchyme = origin of vitreal vessels

 Origin from eye cup
 External layer – pigment epithelium
 Inner layer – proliferates in pars nervosa
 Intraretinal space – gradually disappears
 Inversion of retina

 Fibers from ganglionic cells growth through stalk
 lumen of stalk ceases
 Fissure (invagination) ceases

DEVELOPMENT of the EYE I from CNS
Mesencephalon
BRAIN
Rhombencephalon
35 days pc
3 brain ‘vesicles’ are subdividing now four, then Rhombencephalon divides into Met- & Mel-encephalons
Diencephalon
Cephalic flexure/bend
Cervical flexure start the folding
Telencephalon Surface
ECTODERM
MESENCHYME
Neural
ECTODERM
Already before 35d pc, on each side of the ‘head’, interactions have started between surface
ECTODERM, a bulge of the FOREBRAIN & the
MESENCHYME

EYE PARTS’ EMBRYONIC SOURCES
Surface
ECTODERM
MESENCHYME
Neural
ECTODERM
LENS
CORNEAL
EPITHELIUM
CORNEAL
STROMA
UVEA
SCLERA
RETINA
OPTIC
NERVE
LENS VITREOUS
Connective tissue & muscle (& vessels) come from cranial mesenchyme
Two ectoderms drive events and shaping

ANTERIOR EYE PARTS’ EMBRYONIC SOURCES
Surface
ECTODERM
How does a surface layer produce two separate structures?
In much the same way as an endocrine gland is produced: by a downgrowth of cells that then break off the surface connection LENS
CORNEAL
EPITHELIUM
Here the downgrowth makes the
lens vesicle, conferring a roundish shape from early on
Mesenchyme
To have enough cells for the future cornea and for the lens vesicle, the surface ectoderm first thickens to form a lens placode over the brain-derived optic vesicle

LENS & OPTIC CUP DEVELOPMENT I
While still growing, both placode and end of the optic vesicle invaginate
Mesenchyme optic vesicle
Intraretinal space lens placode
Double wall of optic cup is starting to form
Optic vesicle precedes the lens vesicle and is a distinct structure

OPTIC CUP DEVELOPMENT II: Choroid fissure
Mesenchyme
Blood vessels have to be introduced early into the soon to be enclosed round eye
Together with the invagination centrally at the end of the optic cup, an invagination along the cup & stalk’s inferior surface occurs, to create the choroid fissure in which runs the hyaloid artery

OPTIC CUP DEVELOPMENT II: Coloboma
Mesenchyme
Blood vessels have to be introduced early into the soon to be enclosed round eye
Together with the invagination centrally at the end of the optic cup, an invagination along the cup & stalk’s inferior surface occurs, to create the choroid fissure
Also, an annular vessel runs around the outside of the optic cup in which runs the hyaloid artery
Imagine a penis in which the urethra near & into the glans is still open on its underside - the condition of
hypospadias - (but now contains an artery)
Defects in the eye from failure of the choroid fissure to close are colobomas

a c l p n s l e o d e
OPTIC DEVELOPMENT III: Lens vesicle
Mesenchyme
LENS VESICLE
Mesenchyme
Inner wall thickens
Deeper part of Placode sinks into mesenchyme & makes a vesicle
Optic cup becomes deeper
Attachment to surface ectoderm will be broken so that surface ectoderm can become corneal epithelium & intervening mesenchyme can form the corneal stroma

OPTIC DEVELOPMENT IV: Lens differentiation
Mesenchyme Attachment to surface ectoderm lost
Mesenchyme
Anterior vesicle cells become subcapsular epithelium
Basal lamina becomes lens capsule
Posterior vesicle cells become elongated lens cells
Posterior vesicle cells form the nucleus of the lens.
Subsequent lens cells derive from the subcapsular epithelium

OPTIC DEVELOPMENT IV: Lens differentiation
Mesenchyme
Anterior-vesicle cells become subcapsular epithelium
Basal lamina becomes lens capsule
Lumen obliterated
Posterior-vesicle cells elongate to lens cells
LENS

OPTIC DEVELOPMENT V: Retina differentiation I
Mesenchyme
Outer layer of cup stays thin and beomes pigment cell layer
Intra-retinal space occluded
Inner layer of cup thickens and becomes Neural layer
Hyaloid artery reaches inside cup
After a while, the lens and vitreous no longer need it, and it atrophies. Only the neural retina continues to depend on it, but under another name - central artery of the retina

OPTIC DEVELOPMENT VI: Retina differentiation II
Mesenchyme
Inner layer of cup thickens and becomes Neural layer
Where cells multiply, form layers and differentiate to the several cell types of the neural retina
Outer layer of cup stays thin and beomes pigment cell layer

 Protrusion of both layers of eye cup
 pigment epithelium – from external layer
 Non pigmented epithelium – from inner layer
 Cilliary canal – from cavity of cup
 m. ciliaris and tissue – from mesenchyme

 Margin of eye cup
 External layer changes into smooth muscles
 Inner layer creates pigment epithelium

 Originates from lentiform sac
– Anterior wall is not changing = anterior epithelium
– Posterior wall – cells elongating till lumen extinction
• Origin of primary fibers
• Secondary fibers – from cells of anterior epithelium
– capsula lentis – thickened basal lamina of anterior epithelium


Supplied by a. hyaloidea – ceases
Pupillary membrane – covers lens
– ceases

 Anterior chamber
– Rift between origin of lens and cornea
 Posterior chamber
– Rift inside eye cup alongside lens

 cornea
– Surface mesoderm
– mesenchyme
– Cells of neural crest
 Choroidea and sclera
– Surrounding mesenchyme

 6th week: skin folds over cornea
 10th week: folds connectiong
 28th week: again opening
 During that time from inside attaches conjunctiva
 Muscle from IInd branchial arch
 Tarsal plate and glands from mesenchyme

 Invagination of surface ectoderm
 Non functional till approx. 6th week after delivery
– Newborn is not lacrimating

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





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Inborn retinal dystopia coloboma retinae (usually bilateral – defect of fissura optica closure) cyclopia (1 eye), synophthalmia (fused eyes) microphthalmia – infection anophthalmia coloboma iridis aniridia, aphakia
(6th week – defect of fissura optica closure membrana pupillaris persistens a. hyloidea persistens
Inborn green cataracta; inborn cataracta
Inborn ptosis, coloboma palpebrale
(in galactosemia) cryptophthalmia (eyelids missing – eye covered by skin)

 Slit-lamp
 Examination of the eye ground – oedema of discus/papilla n. optici = increased intracranial pressure
 perimetria = examination of the width of the eye field
 optometria = examination of the quality of vision
 OCT (optical coherence tomography)

OCT
Goldmann applanation tonometry
OCT
Slit lamp

 epiphora (excesive lacrimation)
 myopia – hypermetropie (short – long vision)
 hypermetria (overshooting – lesion of cerebellum!)
 presbyopia (elder eye)
 hemeralopia (anopsia in twilight)
 amblyopia (blunt-sighted) – functional lesion (ce when strabismus)
 daltonismus (colorless vision)