ANATOMY & PHYSIOLOGY EYE

By: Dr Abdul Salim IsmailOphthalmology DepartmentHospital Pulau Pinang8 July 2015

Eye Cavity Shape/Size

pear-shaped

30cc volume

35mm height,

45mmwidth

40-45mm depth

Formation

margin

roof/floor

lateral/medial wall

periorbital sinusesJPG File JPG File

Blow-Out Fracture

Results in antero-posterior compression

Simultaneous expansion in

the equatorial plane

Impact primarily absorbed:lens-iris diaphragmvitreous base

Damage :anterior segmentposterior segment

Blunt Trauma

Skinfine hairs/various glands

MarginSubcutaneous connective tissueOrbicularis oculi muscleOrbital septumLevator/muller’s muscleTarsus plates

Eye Lids

GIF File GIF FileJPG File

JPG File

Lacrimal System

•Epiphora•Acute Dacryocystitis

High contents of nerve axon unlike skeletal muscle

Origin from orbital apex

Insertion on anterior scleral layer

Single/share nerve/blood supply

Extraocular muscles differ histologically from most other skeletal muscles in that they are made up of 2 different types of muscle cells. Each muscle cell is composed of groups of myofibrils called sarcomeres

Extraocular Muscles

Skeletal muscles in that they are made up of 2 different types of muscle cells. Each muscle cell is composed of groups of myofibrils called sarcomeres

Extraocular Muscles

Total six muscles

superior rectus

inferior rectus

medial rectus

lateral rectus

superior oblique

inferior oblique

24mm in diameter

AP diameter 21-26mm

conjuctivae-retina

Eye Globe

Conjunctivae

outermost layer palberal/bulbar

parts nonkeratinizing

squomous epithelium with numerous goblet cells

Sclera opaque and white eye ball integrity

JPG File

Cornea

avascular and transparent 12x11 mm in size consist of 5 layers

epithelium Bowman’s layer stroma descement’s membrane endothelium

main refractive element 70%

Lasik surgery

Keratoconus

Corneal Transplant

Cornea Ulcer

Aqueos humour

produced by ciliary bodies epithelium

provides nutrients needs for cornea/lens

drains endly into schemm’s canal

production/outflow directly influence IOP

PNG File JPG File

Iridocorneal angleAngle Structures

Gonioscopy

Acute angle closure attack

Uveal tract

main vascular compartment of the eye

consists of iris ciliary body choroid

Iris

anterior extension of uveal tract

made up of connective tissue/blood vessels

melanocytes/pigments cells give various colour

central opening(pupil) for for visual axis

dilator/sphinter muscles important for accommodative

Ciliary body

triangular in shape and mainly formed by epithelium/stroma layer

Also contents of ciliary muscles

aqueous humor production and lens accomodation

Choroid

posterior portion of uveal tract

0.25mm in diameters

main vascular supply to posterior eye component

Lens

bioconvex avascular structre and located just behind iris

9-10mm in diameter

held in place by zonular fibers of ciliary body

function as refractive +accomodation

Phacoemulsification

Vitreous

transparent gel like structure due to content of ‘mucopolysaccharide hyaluronic acid’

4ml in volume with 99% water content

important for metabolism intra ocular tissue such as lens,ciliary body and retina

firmly adhered to retina at periphery and presence of traction can lead to retinal tear

Retina

thin transparent structure

main light receptors structure

consists of 10 layers

red reflex due to transmission of light reflected from capillary bed of the choroid

JPG File JPG File

Retinal Breaks

Leads to retinal detachment

Macula (anatomic macula) 4.5mm-6mm diameter centered on the fovea bordered by superior and

inferior temporal arcadesMacula (fovea centralis)

3mm temporal and 1mm inferior to disc

yellow configuration given by presence of xantophyll

1-umbo2-foveala3-fovea4-parafovea5-perifovea

Optic nerve

second cranial nerve

contents of 1 million axons that originated from ganglion cell layer of retina JPG File

Visual Pathway

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