Anatomi dan Embriologi MataJulie D Barliana

Divisi Pediatri OftalmologiDepartemen IK Mata FKUI/RSCM

Anatomi Bola MataKornea Iris Badan siliar Lensa Retina Koroid N Optikus (NII)Badan kaca (vitreus body)

Anatomi Bola MataBadan Kaca (vitreus body)Anterior chamber (Camera Oculi Anterior)Posterior Chamber (Camera Oculi Posterior)Central Vessel RetinaHyaloid Canal)

Development of the EyeI. First noticeable ~ 22days optic groovesdeveloping neural tube

Development of the EyeII. As neural folds fuse (= forebrain formation) optic vesiclesevaginations of forebrain

Development of the EyeIIIa. Induction of lens placode (surface ectoderm)IIIb. Formation of optic stalk and optic cup from optic vesicle

Continued development ofoptic cup and lensOptic cup invagination of distaloptic vesicle to form doublewalledcup

Optic (choroid) fissure sulcus onventral aspect optic cup/stalk(allows passage of vasculatureto lens & layers of cup)

Lens placode ectodermalThickening

Lens pitinvaginates to formlens vesicle

Development of the retinaouter & inner portions of the optic cupClosure of choroid fissure ~ 6-7 weeks

Optic CupInner layer neuroepitheliumneural retinaOuter layerretinal pigmentepitheliumIntraretinal space

Cavity of optic stalk filledwith axons of optic nerveFusion of inner and outerportions of the optic cup

Lens Development

lens placode in surface ectoderminvaginates as lens vesiclesupplied by hyaloid arteryAphakia absence of the lens (extremely rare) Moore and Persaud, 1998Congenital cataracts(e.g., rubella virus)Congenital galactosemiacataract formation within 2-3 weeksof birth (galactose accumulation)

Development of Ciliary Body and Irisboth develop from anterior portions of the optic cup and surrounding mesenchymeCiliary muscle smooth muscle derived from mesenchyme near the margin of the optic cup effects accommodation reflexIridial muscles dilator and sphincter pupillae mm. Smooth muscles derived from neuroectoderm of the optic cup control size of pupillary aperture

Iris dan Badan Siliar

Some Ocular AnomaliesRetinal detachmentbetween inner and outer portions of the optic cup derivatives congenitalfailure of fusion acquiredtraumaDefects in closure of optic (choroid) fissure retinal colobomairidial colobomaAniridia (rare) 1 in 75,000

Extraocular MusclesDevelop from somitomeres I-IV (paraxial mesoderm cranial to the occipital somites)Innervated via CN III, IV, & VICoordinate movements between the two eyes(usually conjugate, although some instancesof physiological vergence exist)

Extraocular mm.Inferior obliqueMedial rectusSuperior obliqueSuperior rectusLevator palpebrae sup.Lateral rectusInferior rectus(not shown)

Oculomotor Nerve (CN III)Somatic motor(oculomotor nucleus):Sup. rectus, Inf. rectus,Med. rectus, Inferior oblique& Levator palpebrae superiormm.Parasympathetic(Edinger-Westphal nucleus):Ciliary m. &Constrictor pupillae m.

Trochlear Nerve (CN IV)Somatic motor only(trochlear nucleus):Superior oblique m.Abducens Nerve (CN VI)Somatic motor only(abducens nucleus):Lateral rectus m.

Extraocular Muscle Anomalies (congenital)

Agenesis (single muscle usually)Anomalous Attachmentsmisplacedadditional attachmentsAdherence & Fibrosis Syndromes**Failure to align visual axes (strabismus), thus potentially resulting in diplopia (double-vision)Amblyopiareduced/absent visual ability in one eye lazy eye

VISUAL REFLEXES

Pupillary Light Reflexes: 30wks gestationConstriction (parasympathetic)Dilation (sympathetic)Accommodation (4 months = well developed)(The Near Reflex)

Visual Developmental Milestones

Pupillary Light Reaction30 wks gestation(CN II/symp/parasymp integration)Lid closure in response to bright light30 wks gest.(CN IICN VII reflex)Blink response to visual threat2-5months(CN IICN VII reflex)Visual Fixationbirth (well dev=6-9wks)Visual Following3 monthsAccommodation4 months

ResourcesThe Developing Human6th Edition K. L. Moore & T. V. N. Persaud 1998The EssentialsWalsh & Hoyts ClinicalNeuro-Ophthalmology5th EditionEditorsN.R. Miller and N.J. Newman1999Neuro-ophthalmology3rd EditionEditorJ.S. Glaser1999

Growth and Developmental of the Eye

Dimensions of the EyeMost of growth of the eye takes place in the first year of lifeThe axial length occurs in 3 phasesPhase I: rapid period of growth (6 mos)-AL increases 4 mmPhase II and III: (age 2-5 years) and (age 5-13 years) growth slows-about 1 mm

KeratometryCornea grows rapidly over the first several months of life (6 mos)Keratometry values change ,markedly in the first year of life:52 D at birthFlattening to 46 D by 6 monthsReaching adult power of 42-44D by age 12

Corneal horizontal diameter9.5-10.5 mm at newborns12 mm in adulthoodMost of changes occurs in the first year of life

Lens PowerThe power of the infant lens decreases dramatically over the first several years of life, an important fact to consider when implanting intraocular lenses (IOLs) in children undergoing cataract extraction in infancy and early childhood

Refractive ErrorsThe refractive state of the eye changes as The AL increasesThe cornea and lens flattenIn general:Infants are hyperopic at birth, become slightly more hyperopic until age 7, and a myopic shift until the eye reaches its adult size, usually by about age 16

Visual acuity and StereoacuityTwo major methods are used to determine VA in preverbal infants and toddlers:Visual evoked potentials (VEP) Preferential looking (PL)VEP shows improvement of vision from about 20/400 in infancy 20/20 by age 6-7 mosPL studies estimate the vision of a newborn infant 20/600, 20/120 by 3 mos and 20/60 by 6 mos.20/20 at 3-5 years

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