anatomy and patho of eye

Question 1

sclera

Answer 1

white outer protective layer

Question 2

conjunctiva

Answer 2

clear mucous membrane that covers the sclera

Question 3

choroid

Answer 3

vascular layer that provides oxygen and nutrients to eye

Question 4

bulbar conjunctiva

Answer 4

clear mucous membrane that covers the sclera up to cornea

Question 5

palpebral conjunctiva

Answer 5

lines the inside of the eye lids

Question 6

retina

Answer 6

neural tissue containing the photoreceptors

Question 7

cornea

Answer 7

modifed transparent sclera that allows light to enter the eye

Question 8

optic disk

Answer 8

where the optic nerve leaves the eye this area of retina does not respond to light and is known as blind spot

Question 9

macula

Answer 9

yellowish pigmented spot at back of the eye which contains the fovea a thinned out, cone only portion of the retina where visual acuity is greatest

Question 10

age related macular degeneration

Answer 10

disease in which sharp, central vision is gradually destroyed
- progressive, chronic disease of centrak retina, resulting in rapid vision loss if untreated

2 processes:
dry and wet

Question 11

dry

Answer 11

geographic atrophy
yellow lipid deposits form under the retinal epitheliym
losss of retinal epithelium, capillaries and photoreceptors

Question 12

wet

Answer 12

exudative
involves neovascularisation of choroidal blood vessels into the retina, leaking fluid, lipids, blood and leading to fobrous scarring
choroidal neovascularisation at this stage is treatable
post 3 years damage is permanent with loss of centreal vision

Question 13

scotoma

Answer 13

loss of central vision

Question 14

risks for macular degeneration

Answer 14

smoking
obesity
low intake of Vitamin A, C, E and zince, lutein and omega 3 fatty acids
cardiovascular risk factors

Question 15

life mods

Answer 15

stop smoking
loss weight
dietary supplements
antihypertensive and lipid/cholesterol lowering therapies if indicated

Question 16

treatments for wet macular degeneration

Answer 16

therapy surpresses the action of vascular endothelial growth factor which is a key regulator of neovascularization pathogenesis
ranibizumab
bevacizumab
aflibercept

Question 17

ranibizumab

Answer 17

antibody fragment that binds all VEGF isoforms
improves vision when IV
expensive
1/3 have positive outcome over 7 years

Question 18

bevacizumab

Answer 18

antibody against VEGF approved for colon cancer

Question 19

aflibercept

Answer 19

acts like VEGF receptor
selectively binds VEFG A, key regulator isoform

Question 20

retinopathy

Answer 20

bilateral bulls eye pattern of retinal damage
central, concentric, parafoveal
progresses centrally toward fovea

Question 21

retinopathy risk factors

Answer 21

duration of use (> 5 years, high cumulative dose >1kg)
concomitant treatment with tamoxifen
sig renal disease
peexisting retinal and macular disease

Question 22

retinopathy mechanism

Answer 22

hydroxychloroquine inhibits uptake of all vitamin a by retinal pigment epithelium cells
photoreceptors contain rhodopsin or photopsin, GPVR that contains retinal
Vit A is thr percursor of retinal and thus depeltes retinal in RPECs

Question 23

hydroxychloroquine

Answer 23

t1/2= 40-50 days therefore lasting effects for months
accumulation in tissues not blood
5 or lessmg/kg, max 400 mg tp avoid retinal toxicity

Question 24

lacrimal gland

Answer 24

secretes tears to spread over eyeball by blinking and removes dust and foreign particles

Question 25

lacrimation

Answer 25

lubricating eyeball via lacrimal gland parasympathetic innervation VII nerve via pterygopalatine ganglion activates M3 receptors on secretory globular acinar cells to stimulate tear secretion drain via nasolacrimal duct

Question 26

dacryostenosis

Answer 26

obstruction of nasolacrimal duct

Question 27

dacryocystitis

Answer 27

infection of lacrimal sac S aureus S pneumonia H influenzar S macroessans P aeruginosa

Question 28

dry eye

Answer 28

discomfort and visual disturbances (intrinsic vs extrinsic)

Question 29

changes contributing to xerophthalmia

Answer 29

- decreased tear production -increased evaporation of tear film due to dysfunction of meibomiam glands - most have a combo -late stage assoicated with conjunctival scarring and corneal complication

Question 30

meibomiam gland

Answer 30

orifices on eyelid margin blocked by thickened meibomian secretion

Question 31

conjunctiva

Answer 31

parasympathetic nerves acting on M3 receptos cause goblet cells in the conjunctival epithelium to release mucin and other protein secretion into the tear for lubrication muscarine receptor antagonist can cause dry eyes by blocking activation of m3

Question 32

sjogren syndrome

Answer 32

automimmune disorder of mucous membrane which leads to dryness of eyes, mouth, skin, nasal and vaginal passages women have antibodies to m3 receptor which disrupts lacrimal and salivary gland function leading to xerostomia and xerophthalmia treatment: muscarinic receptor agonists

Question 33

conjunctivities

Answer 33

inflammation of tranparent lubricating mucous membrane that covers the globe of the eye and under surface of eyelid symptoms: discharge, erythema, pruritis allergy, viral, bacterial

Question 34

external hordeolum

Answer 34

stye staph infection of hair follicle of eye lid upper more often pimple like abscess which can swell reddening eye lid and resulting in pain zeis (sebum) and moll (igA, mucin and lysosomes) blackade of thes due to thickening, drying and stasis of their secretin promotes infection

Question 35

internal hordeolum

Answer 35

infection of meibomiam glan in conjunctive meibomiam glands are type of sebaceous gland that produce an oily layer which aids in lubrication more painful

Question 36

chalazion

Answer 36

cyst like nodules that remain post hordeolum red but not painful

Question 37

blepharitis

Answer 37

inflammation of eyelids often at base of eyelashes erythematous, pruritic eyelids, conjunctival injection, crusting or matting of eyelids and occasionally flaking of eyelid skin