By- Dr. Armaan Singh

Complete Eyeball Info ppt.

Eyeball

• Surrounded by Tenon’s fascia

• Attached to corneoscleral junction

• Dura on optic nerve

• Check ligaments

• Suspensory ligament of Lockwood

• Cone of muscles

• Fat

Eyeball• Consists of three coats

• Outer layer

• Sclera and cornea

• Choroid

• Retina

Cornea• Transparent

• Avascular

• Forms anterior 1/6

• Smaller sphere than sclera

• Depression at corneoscleral junction

Five Layers of Cornea1. Corneal epithelium

2. Bowman’s or anterior limiting membrane

3. Substantia propria

4. Descement’s or posterior limiting membrane

5. Endothelium

Cornea• Posterior limiting membrane

breaks up at the edges to form pectinate ligament of iris

• Spaces are called the spaces of the iridiocorneal angle (fontana)

Iridiocorneal Angle

• If the iridiocorneal angle is narrowed

• Reabsorption of aqueous humour into venous sinus of sclera is blocked

• Causing glaucoma

• Blindness increased intraocular pressure

Cornea

• Cornea is avascular

• Surface must be moist

• Rheumatoid dry

• Not wearing safety goggles

• Scarring of cornea results in blindness in that portion of the cornea

• Trachoma, new vessel formation in the cornea

• Transplants

Sclera• Posterior 5/6

• Opaque

• Insertion muscles

• Vena vorticosae pierce at equator

• Optic nerve 2.3 mm medial to axis, the lamina cribrosa

• Central artery of retina

• Long and short cilary vessels and nerves

Suprachoroid Space• Long ciliary nerves

• Long posterior ciliary arteries going to iris

Choroid• Choroid proper

• Ciliary body

• Iris

• Vascular layer in posterior part

• Equator of eyeball

• Uveal tract or iridocyclitis

Choroid

• Outer limiting membrane

• Veins

• Arteries

• Capillaries

• Inner limiting membrane of bruch

• Attached to pigmented layer of retina

Ciliary Body

• Triangular

• Apex posterior

• Short base anterior

• Deep surface thrown into folds called the ciliary processes

• Ciliary body is vascular, pigmented

Ciliary Zonule• Suspensory ligament of lens is

attached to the cilary processes

• The portion of the suspensory ligament closest to the ciliary

• Processes is called the ciliary zonule

Ciliary Muscles

• Smooth muscle

• Radial is attached to scleral spur

• Circular within anterior part of radial muscle

• Parasympathetic oculomotor 3rd nerve

• Relays in ciliary ganglion

Accommodation Reflex

• Contraction of ciliary muscles

• Ciliary processes pulled anteriorly

• Relaxes suspensory ligament of lens

• Elasticity of lens

• It becomes more convex

• Pupils constrict

• Medial rectus contracts

Iris

Iris• Cone shaped diaphragm

• Halfway along anterior of base of choroid

• Central aperture pupil

• Vascular pigmented

• Amount pigment colour

• Blood vessels long posterior, anterior cilary arteries; two circles

Iris

• Circular sphincter pupillae

• Oculomotor

• Behind lies radial or dilator pupillae

• Sympathetic T1 develop from ectoderm

Aqueous Humour• Aqueous humour is secreted by

ciliary processes into posterior chamber

• Through the pupil into anterior chamber

• Spaces of fontana into venous sinus of sclera or canal of Schlemn

Posterior Chamber

• Bounded posteriorly by suspensory ligament of lens and lens

• Peripherally by ciliary processes

• Anteriorly by iris

Anterior ChamberAnterior Chamber

• Bounded posteriorly by iris and pupil

• Anteriorly by cornea

• Peripherally by spaces of fontana or iridio-corneal angle

Retina• Nervous layer

• Superficial to deep

• Pigment cells

• Rods and cones

• Bipolar cells

• Ganglion cells

• Axons of the ganglion cells form optic nerve

Rods • Rods are found at peripheral

portion of the retina

• 70 rods connected to one bipolar cell

• Peripheral vision

• Visual purple sees back and white

Cones

• Cones see colour

• Photoreceptors

• One cone to one bipolar cell

• Found in fovea or macula lutea

• Directly behind axis

• No nerve fibres or vessels in front

Blood Supply of Retina

• Rods and cones supplied by capillaries of choroid by diffusion

• Bipolar and ganglion cells supplied by central artery of the retina

• Enters through optic disc, blind spot

Optic Disc

Diabetic Hypertensive

Detached Retina• Outer layer of optic cup

• Pigmented layer

• Inner layer rods and cones

• Removed from their blood supply

Refractive Media• Cornea

• Aqueous humour of anterior and posterior chamber

• Lens

• Vitreous body

Refractive Media• Greatest refraction of light

• Takes place at the surface of the cornea

• Very little refraction after

cornea

Lens• Crystalline

• Translucent

• Avascular structure

• Lies in hyloid fossa

• Posterior surface is highly convex

• Does not alter its shape

Lens• Suspensory ligament is

attached to periphery of the lens

• Cataract opaque lens

• Nutrition from aqueous humour

Lens• Supplied by hyloid

• Artery during development

• Hyloid artery regresses remains as the hyloid canal

• May persist, result a form of blindness

Vitreous Body• Semiliquid

• Translucent

• Avascular gel

• Enclosed in hyloid membrane

• Opacities may develop in elderly

Subconjunctival Haemorrhage