Cornea

Question 1

In come people the corneal dendritic scar (with bulbous ends) heals, but what are some of the complications that could arise for those who dont heal?

Answer 1

if the infection is confined to the epithelium, healing occurs without scarring.
Sometimes stromal inflammation may occur and so this can lead to some level of scarring.
anterior uveitis can occur

Question 2

what can happen if you put a topical steroid on a herpetic corneal ulcer?

Answer 2

results in an amboeid ulcer and is slow to heal and very hard to treat.

Question 3

what are some complications of herpes zoster virus?

Answer 3

conjuctivitis
keratitis
anterior uveitis
scleritis and episcleritis

Question 4

What are three viruses that can affect the cornea?

Answer 4

herpes simplex
herpes zoster
adenovirus

Question 5

WHat are predisposing factors that make bacterial infection likely to happen in the cornea?

Answer 5

corneal trauma
contact lens wear
chronically compromised ocular surface such as dry eye, blepharitis and keritopathy
hepatitis keratitis
corneal exposure (facial nerve palsy (cant close eyes) and proptosis)
immunosupression, including topical steroid use

Question 6

what is the management for bacterial keratitis?

Answer 6

urgent investigation and admission!
conjuctival and corneal samples sent for microscopy and culture
broad-spectrum topical antibiotics such as quinilone, are administered frequently 24 hrs per day, intially until a favourable response is seen.
sometimes subconjuctival and systemic antibotics are given
despite the liklihood of permanent scarring topical steroids are only used when resolution of the infection element.

Question 7

what is marginal keratitis?

Answer 7

blepharitis is a common cause of marginal corneal ulceration which is a hypersensitivy reaction to bacterial toxins - NOT an infection

Question 8

what are the three types of corneal transplantation one can do?

Answer 8

penetrating keratoplasty - full thickness
deep anterior lamellar keratoplasty - partial thickness leaving endothelium in place
endothelial keratoplasty - just the endothelium is transplanted

Question 9

what causes corneal melting?

Answer 9

infection
reduction of tear flow
autoimmune process

Question 10

sx of adenovirus keratitis?

Answer 10

blurring and photophobia after viral conjuctivits

Question 11

What is recurrent corneal erosion syndrome?

Answer 11

caused by epithelial or stromal dystrophy or by previous trauma

Question 12

what are some systemic associations with cataract?

Answer 12

diabetes
corticosteroid therapy
hypocalcemia and other metabolic disorders

Question 13

what are the three types of cataracts that can develop?

Answer 13

nuclear scelrosis - central opacity
posterior subscapular - back of capsule
cortical - spoke like opacities of the cortex

Question 14

What are some caused of leukocoria? (white pupil)

Answer 14

cataract
retinoblastoma
retinopathy of prematurity
corneal opacity
coat's disease

Question 15

what is ectopia lentis?

Answer 15

a disolcated lens - causes include trauma, marfans, cataract

Question 16

WHat is the difference between open and close angle glaucoma?

Answer 16

Open-angle is when there is an open and wide angle between iris and cornea, develops over a very long time and symptoms are not always known.
Angle-closure is when there is a closed and sharp angle, happens quickly and symptoms are very obvious.

When the block is at the entrance it is called Closed Angle Glaucoma. When the blockage is not at the entrance, but beyond, somewhere inside, we call it Open Angle Glaucoma. Closed angle is assosciated with a pupillary block.

Question 17

WHat are the sx of close angle vs open angle glaucoma?

Answer 17

open angle:
not much

closed angle:
pain, nausea and vomiting
loss of vision
red eye (usually unilateral)
cloudy cornea 
a hx of a previous attack

Question 18

what is the surgical procedure for open vs closed angle glaucoma?

Answer 18

open-angle: trabeculectomy

closed-angle: iridotomy

Question 19

How can you test if there is a pupil sympatehtic problem?

Answer 19

cocaine test - 4% cocaine solution into eye and if pupi does not dilate (which a normal one would) then this indicates a loss of sympathetic innervation.

Question 20

What is denervation hypersensitivity?

Answer 20

This is when postganglionic fibers are damaged and so the iris creates more receptors and therefore reacts to a smaller concentration of neurotransmitters than it normally should

Question 21

How can you test for denervation hypersensitivity?

Answer 21

postganglionic parasympathetic lesions - pilocarpine 0.1% - affected pupils will constrict while normal pupils will not

postganglionic sympathetic lesions - 0.1% adrenaline - affected pupils will dilate while normal won’t.

Question 22

how are the pupils affected in third nerve palsy?

Answer 22

dilated pupil that fails to react to light.

also has ptosis and down and out eye.

Question 23

What is Adie’s pupil?

Answer 23

damaged postganglionic parasympathetic fibers causes a semi dilated pupil that reacts poorly to direct light and to accommodation. redilation is slow.
cause unknown - likely viral???
diagnosed with hypersensitivity to 0.1% pilocarpine.

Question 24

What is Horner’s syndrome?

Answer 24

miosis, ptosis and anhydrosis
most obvious in a dim room when the horner’s eye fails to dilate.
cocaine 4% dilates the normal pupil but not the horner’s one. whereas adrenaline 0.1% dilates the horner’s pupil but not the normal one. (since cocaine only prevents reuptake of adrenaline)
investigate for a pancoast tumour in the lung.

Question 25

what is RAPD good for testing which conditions?

Answer 25

test is positive in unilateral disease in the optic nerve,
retinal detachment
severe wet macular degeneration

negative in
cataracts
corneal opacity
vitreous hemmorhage

Question 26

What is scintillating scotoma? and what are the causes?

Answer 26

a kaleidoscope pattern (shattered glass), water running down a window kind of distortion of vision.
This is often seen when the retina or cerebral cortex is being underperfused such as in:
migraine
emboli
giant cell arteritis

Question 27

what are floaters and what are the causes?

Answer 27

floaters are objects seen in vision such as cobwebs, a hair, tadpoles in vision.
causes include anything occurring in the vitreous:
vitreous degeneration or posterior vitreous detachment
vitreous hemorrhage
posterior uveitis.

Question 28

what is happening when someone sees a flickering light?

Answer 28

when a vitreous detachment occurs the posterior vitreous gel may exert traction on the retina, stimulating the retina to see a flickering light.
the traction may tear the retina.

Question 29

what questions should you ask when someone has flashes of light that come and go in the past 5 years?

Answer 29

how long do these episodes last? - 5-20mins suggests a migraine
do you have any assosciated headache that comes after these visual sx? - migraine is usually unilateral throbbing nature.
do you have any hx of diabetes, heart disease, hyperlipideamia, previous stroke/tia, peripheral vascular disease, do you smoke?, arteritis?
do you have a family hx of migraines?
are you on the COC pill?
other neuroligical sx?

Question 30

What is the treatment for corneal abrasion (severe)?

Answer 30

chloramphenicol ointment
dilating drops for comfort
occlusive dressing pad

Question 31

what is corneal abrasion syndrome?

Answer 31

recurrent corneal abrasion syndrome is caused when the attachment of the epithelium to the basement membrane is weak.
it causes episodic sx of:
pain and watering especially in the morning

between attacks, nothing is usually seen on pentorch other than punctate fluorescein staining

Question 32

what is the management of corneal abrasion syndrome?

Answer 32

regular lubrication using artificial tears during day and ointment at night

Question 33

what is someone at risk of developing if they had been kicked in face?

Answer 33

corneal abrasion
acute and chronic glaucoma
pressure on optic nerve and other cranial nerves due to swelling and face frcatures 
vitreous hemmorhage 
retinal damage 
orbital blow out fracture

Question 34

what are the clinical features of an orbital blow out fracture?

Answer 34

enophthalmos - initially can be masked by orbital hemmorhage
altered face sensation of the infraorbital nerve (cheek)
reduced vertical ocular movement - causes vertical double vision.