Ocular AnatomyS.Khairallah, M.D.1 مقرر طب وجراحة العيون الفصل الثاني...

Ocular Anatomy S.Khairallah, M.D. 1

العيون وجراحة طب مقررلعام – الثاني هـ1428/1429الفصل


OCULAR ANATOMYOCULAR ANATOMY

• GLOBE (EYE BALL)• CONJUNCTIVA & EYELIDS• LACRIMAL SYSTEM• EXTRAOCULAR MUSCLES• NERVES• ORBIT


THE GLOBE(EYEBALL):THE GLOBE(EYEBALL):

• TOPOGRAPHY & OPTICAL SYSTEM• LAYERS(COATES)• CHAMBERS• LENS & ZONULES


THE EYEBALL,cont’d:

• TOPOGRAPHY & OPTICAL SYSTEM:Axial length ..24 mm.Equator ..16 mm.posterior to limbusDiopteric power:

cornea … 40 Dlens … 20 D


COATES OF EYECOATES OF EYE

OUTEROUTER MIDDLEMIDDLE

“Uveal tract”

INNERINNER

CORNEA IRIS RETINA

LIMBUS CILIARY BODY

_____

SCLERA CHOROID _____


OUTER COATE (LAYER):OUTER COATE (LAYER):

• PRECORNEAL TEAR FILM• CORNEA• SCLERA• LIMBUS


PRECORNEAL TEAR FILM:PRECORNEAL TEAR FILM:

• THREE LAYERS:– Outer most : lipids …Meibomian ,

Zeiss and Moll glands – Middle : aqueous(watery) …Lacrimal

and accessory lacrimal glands– Inner most : mucinous(mucoid) …

Goblet cells


PRECORNEAL TEAR FILM:PRECORNEAL TEAR FILM:

• FUNCTIONS:– Optical clarity– Nutrition– Defense mechanism


CORNEA :CORNEA :

• THREE LAYERS:– Epithelium / Bowman’s membrane– Stroma– Endothelium / Descemete’s membrane

• DIAMETER : 12 mm.Horiz. / 11 mm.Vertic.

• NERVE : Trigeminal,nonmylinated• BLOOD SUPPLY: NONE “AVASCULAR”


SCLERA :SCLERA :

• THREE LAYERS : – Episclera– Stroma– Lamina fusca

• TWO OPPENINGS : anterior & posterior

• THICKEST ..1 mm. , THINNEST..0.3mm

• NERVES : anterior;long ciliary n. posterior;short ciliary n.

both:sensory from trigeminal n.:EXTREMELY PAINFULL WHEN INFLAMMEDEXTREMELY PAINFULL WHEN INFLAMMED


SCLERA,cont’d:

• BLOOD SUPPLY:– Episclera & choroidal vesseles.– Anterior to recti muscle’s insertion:-

• Anterior ciliary arteries ciliary injection

– Posterior to recti muscle’s insertion:-• Posterior ciliary arteries

• LYMPHATICS :• None


LIMBUS:LIMBUS:

• It is corneo-scleral junction• Covered by conj./Tenon’s capsule• Aqueous humor drainage system• Nerves:autonomic n.& sensory

from trigeminal n.• Blood:ant.ciliary

arteries&episcleral vesseles




“Uveal tract”

INNERINNER

CORNEA IRIS RETINA

LIMBUS CILIARY BODY

_____



MIDDLE COATE:MIDDLE COATE:

• =Uveal tract (uvea = grape (عنب

• 3 parts :

ANTERIOR INTER-MEDIATE

POSTERIOR

IRIRS CILIARYBODY

CHOROID


IRIS (IRIS (:(:(القزحيةالقزحية

• It has a central hole (pupil) to control light entering the eye ( ↓ glare)

• It’s thinnest at its insertion to Ciliary Body! (traumatic iris dialysis)

• Two layers: anterior stroma posterior epithelium• Two muscles: sphincter pupillae m.

(para.n.) dilator pupillae m.(sym.n.)


IRIS,IRIS,cont’d:

• Blood : major arterial circle of iris• Nerve : sensory,nasociliary n.(5th

C.N.)


CILIARY BODY:CILIARY BODY:

• It’s a triangular organ,base forward• Two portions: uveal & epithelial

– Uveal portion:3 muscles;longitudinal,radial and circular

– Epithelial portion:pars plicata & pars plana

• Blood:majot arterial circle of iris• Nerve:short ciliary nerves


CHOROID:CHOROID:

• It’s posterior part of uveal tract

• It’s 3 vascular layers , inner most :

choriocapillaris

• Blood: anterior & post. Ciliary arteries , drainage via vortex veins

• Nerve : short ciliary nerves




“Uveal tract”

INNERINNER

CORNEA IRIS RETINA

LIMBUS CILIARY BODY

_____



Eyeball,INNER COATE:INNER COATE:

• RETINA :– Two major layers:

• Retinal pigment epithelium ( RPE) .. Outermost• Neuro-sensory retina .. Innermost :

– Subdivided into 10 layers :» Photoreceptors (rods,cones) … outermost » Nerve fiber layer … innermost

– Centrally : Macula , fovea , foveola

– Blood : choriocapillaris & central retinal artery

– Functions :


Eye,CHAMBERS:CHAMBERS:

ANT.CHM.

POS.CHM

VIT.CAVIT

Anteriorly Cornea Iris L.,zon.,CB

posteriorly

Iris,lens Ant vit face Ret.,opt.n.

Laterally A/c angle Cil process Retina

medially --- Lens equato

---

volume 0.20 ml 0.06 ml 4.50 ml

Filled by Aqueous h. Aqueous h. Vitreous h.


Anterior chamber ANGLE:Anterior chamber ANGLE:

• Between peripheral cornea & iris root• ANGLE STRUCTURES: anterior to posterior

– Schwalbe’s line– Trabecular meshwork Schlemm’s canal– Scleral spur

• FUNCTION : Drainage of aqueous humor


Eyeball , LENS:LENS:

• Biconvex,transparent,colorless• No vesseles,no nerves• Held in position by zonules• 10 mm.in diameter,4 mm.thick• Consist of :

– Lens capsule– Anterior lens epithelium– Lens substances: cortex(new

f.)&nucleus(old f.)


LENS ..cont’d:LENS ..cont’d:

• Lens suture lines:ant.”y”,post.inverted”y”

• Contains 65% water , 35% proteins , trace minerals ,↑ K+ ,ascorbic acid and glutathione.

• AGING:– Larger– Harder(less elastic)– Coloring: yellow deep brown.why?


ZONULE :ZONULE :

• = Zonule of Zinn , suspensory ligament

• Collagen fibrils• Attach to nonpigmented

epithelium of ciliary body and either sides of lens equator


اليك .. أتوب و اللهم استغفرك وبحمدك اللهم سبحانك

Ocular AnatomyS.Khairallah, M.D.1 مقرر طب وجراحة العيون الفصل الثاني...

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