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  • Professor Emeritus Moira OBrienFRCPI, FFSEM, FFSEM (UK), FTCDTrinity CollegeDublinEyeball

  • EyeballSurrounded by Tenons fasciaAttached to corneoscleral junctionDura on optic nerveCheck ligaments Suspensory ligament of LockwoodCone of muscles Fat

  • Consists of three coatsOuter layerSclera and corneaChoroidRetina


  • CorneaTransparentAvascular Forms anterior 1/6 Smaller sphere than scleraDepression at corneoscleral junction

  • Five Layers of CorneaCorneal epitheliumBowmans or anterior limiting membraneSubstantia propriaDescements or posterior limiting membraneEndothelium

  • Posterior limiting membrane breaks up at the edges to form pectinate ligament of irisSpaces are called the spaces of the iridiocorneal angle (fontana)


  • Iridiocorneal AngleIf the iridiocorneal angle is narrowedReabsorption of aqueous humour into venous sinus of sclera is blockedCausing glaucomaBlindness increased intraocular pressure

  • Cornea is avascularSurface must be moist Rheumatoid dryNot wearing safety gogglesScarring of cornea results in blindness in that portion of the corneaTrachoma, new vessel formation in the corneaTransplants


  • ScleraPosterior 5/6 Opaque Insertion musclesVena vorticosae pierce at equatorOptic nerve 2.3 mm medial to axis, the lamina cribrosaCentral artery of retina Long and short cilary vessels and nerves

  • Suprachoroid SpaceLong ciliary nervesLong posterior ciliary arteries going to iris

  • ChoroidChoroid properCiliary bodyIrisVascular layer in posterior partEquator of eyeballUveal tract or iridocyclitis

  • Outer limiting membraneVeinsArteriesCapillariesInner limiting membrane of bruch Attached to pigmented layer of retinaChoroid

  • Ciliary BodyTriangularApex posteriorShort base anteriorDeep surface thrown into folds called the ciliary processesCiliary body is vascular, pigmented

  • Ciliary ZonuleSuspensory ligament of lens is attached to the cilary processesThe portion of the suspensory ligament closest to the ciliary Processes is called the ciliary zonule

  • Ciliary MusclesSmooth muscleRadial is attached to scleral spurCircular within anterior part of radial muscleParasympathetic oculomotor 3rd nerveRelays in ciliary ganglion

  • Accommodation ReflexContraction of ciliary musclesCiliary processes pulled anteriorlyRelaxes suspensory ligament of lensElasticity of lens It becomes more convexPupils constrictMedial rectus contracts

  • Iris

  • Cone shaped diaphragmHalfway along anterior of base of choroidCentral aperture pupilVascular pigmentedAmount pigment colourBlood vessels long posterior, anterior cilary arteries; two circlesIris

  • Circular sphincter pupillae OculomotorBehind lies radial or dilator pupillaeSympathetic T1 develop from ectoderm Iris

  • Aqueous HumourAqueous humour is secreted by ciliary processes into posterior chamberThrough the pupil into anterior chamberSpaces of fontana into venous sinus of sclera or canal of Schlemn

  • Posterior ChamberBounded posteriorly by suspensory ligament of lens and lens Peripherally by ciliary processesAnteriorly by iris

  • Anterior ChamberAnterior ChamberBounded posteriorly by iris and pupilAnteriorly by corneaPeripherally by spaces of fontana or iridio-corneal angle

  • RetinaNervous layerSuperficial to deepPigment cellsRods and conesBipolar cellsGanglion cellsAxons of the ganglion cells form optic nerve

  • Rods Rods are found at peripheral portion of the retina70 rods connected to one bipolar cellPeripheral visionVisual purple sees back and white

  • ConesCones see colour PhotoreceptorsOne cone to one bipolar cellFound in fovea or macula luteaDirectly behind axisNo nerve fibres or vessels in front

  • Blood Supply of RetinaRods and cones supplied by capillaries of choroid by diffusionBipolar and ganglion cells supplied by central artery of the retina Enters through optic disc, blind spot

  • Optic Disc

  • Diabetic Hypertensive

  • Detached RetinaOuter layer of optic cupPigmented layerInner layer rods and conesRemoved from their blood supply

  • Refractive MediaCorneaAqueous humour of anterior and posterior chamberLensVitreous body

  • Greatest refraction of light Takes place at the surface of the corneaVery little refraction after cornea Refractive Media

  • LensCrystallineTranslucentAvascular structureLies in hyloid fossaPosterior surface is highly convexDoes not alter its shape

  • Suspensory ligament is attached to periphery of the lensCataract opaque lensNutrition from aqueous humourLens

  • Supplied by hyloid Artery during developmentHyloid artery regresses remains as the hyloid canalMay persist, result a form of blindness


  • Vitreous BodySemiliquidTranslucentAvascular gelEnclosed in hyloid membraneOpacities may develop in elderly

  • Subconjunctival Haemorrhage

  • BMJ Publishing Group Limited (BMJ Group) 2012. All rights reserved.

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