Anatomy Flashcards
Choroid
vascular layer between retina and sclera
BVs to nourish outer layers of retina
produce heat exchange from retina
conduct BVs to ant regions of eye
assists in IOP regulation
pigment cells absorb excess light penetrating retina - prevents reflection
Posterior vitreous detachment
increase in age = decrease gel structure
and increase liquid volume
pulls away from retina
casts shadow on retina — seen as floaters
traction on retina - creates retinal tear and fluid seeps underneath retina = retinal detachment - seen as shower floater and curtains closing over eye
urgent referral
Cx of diabetic retinopathy
Flow of aqueous
ciliary body posterior chamber pupil anterior chamber trabecular meshwork Schlemm's canal Episcleral venous system
Ciliary body
Gives rise to zonules
Epithelium secretes aqueous
Ciliary muscle - accommodation of lens
Supplied by SNS
Muller’s muscle
Dilator pupillae
Ciliary epithelium
Supplied by PNS
Constrictor pupillae
Ciliary muscle
Media of eye
cornea anterior chamber lens posterior chamber vitreous
Components of urea
iris
ciliary body
choroid
Myopia
short sightedness = corrected biconcave lenses
eyes look small through glasses
Hypermetropia
far-sightedness = corrected biconvex lenses
eyes look big through glasses
Presbyopia
age related loss of lens elasticity
cannot accommodate for near vision
needs reading glasses/bifocals
Astigmatism
Light not evenly focused on retina
Extra-ocular muscles functions
MR = adduction LR = abduction IO = extorsion SO = intorsion SR = elevation IR = depression
SOF
superior ophthalmic vein
CN III, IV, VI and ophthalmic division of trigeminal
lacrimal frontal and nasociliary nerve
IOF
maxillary division of trigeminal
inferior ophthalmic vein
Optic canal
CN II and ophthalmic artery
Layers of retina
Inner limiting membrane Neural fibre layer Ganglion cell layer Inner plexiform layer Inner nuclear layer Outer plexiform layer Outer nuclear layer External limiting membrane Photoreceptor layer Retinal pigmented epithelium
Normal
Cup:Disc
AV ratio
4: 10
2: 3
Ocular pathway
CNII optic chiasm optic tract LGB optic radiations visual cortex in occipital lobe
Accommodation
lens becomes more globular
pupil constricts
eyes converge
Levator palpebrae superioris
CN III
trauma = ptosis
Rods vs Cones
Rods
- 1 type = black and white vision
- peripheral vision
- vision in dim light
- not present at fovea but present everywhere else
- slow response
Cones
- 3 types - colour vision
- central vision
- vision in bright light
- highest density at fovea and macula
- fast response
