Ophthalmology intro and adnexa Flashcards

1
Q

What direct opthalmoscope settings do we use to look at tapetal reflex

A

0 dioptres
Go from about 2 foot away

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2
Q

What might decrease or increase the tapetal reflex

A

Decrease: cataracts
Increase: retinal atrophy

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3
Q

How to differentiate nuclear sclerosis from true cataract

A

True cataract does obscure the tapetal reflex
Nuclear sclerosis doesn’t obscure tapetal reflex (=pseudoopacity)

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4
Q

How to look at the posterior section of the eye with direct opthalmoloscope

A

Still use 0 dioptres
Go 2-3cm away from eye for highly magnified view of fungus

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5
Q

What is myopia and hypermetropia and how do we compensate for this when we want to look at the fundus

A

Myopia = short sightedness
Hypermetropia = long sightedness
Compensate via adjusting dioptres setting

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6
Q

What direct ophthalmoloscope settings do we use to look at anterior segment of the eye

A

10 dioptres

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7
Q

What shape do the anterior vs posterior suture lines of the lens make

A

Anterior = Y shape
Posterior = inverse Y

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8
Q

What setting do we use to look at cornea and adnexa on direct ophthalmoscopy

A

20-30 dioptres

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9
Q

Properties of indirect ophthalmoscopy

A

Less magnified
Inverted, virtual image
Good for scanning retinas

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10
Q

What is gonioscopy and what is it useful in identifying

A

= using contact lens for visualising the iridocorneal angle
Can be diagnostic in glaucoma

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11
Q

What is a normal Schirmer tear test result and what is clinical dry eye

A

Normal = 10-20mm/min
Dry eye = 5mm/min

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12
Q

How does indentation tonometry work

A

Pushes probe on surface of eye and sees how much it indents; more indentation = lower intraocular pressure

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13
Q

How does applanation tonometry work e.g tonopen

A

How much pressure does it take to flatten middle 0.5cm of cornea; less pressure means lower intraocular pressure

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14
Q

How does rebound tonometry work e.g tonovet

A

Speen of rebound of probe going onto eye

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15
Q

What is normal intraocular pressure
- What in glaucoma
- What in inflammation

A

Normal = 15-22mmHg
Glaucoma = 30-60mmHg
Inflammation = 10mmHg

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16
Q

Why do we flush eye after putting in Fluorescein isothiocyanate stain

A

Because re-epithelialised ulcer will have dip in the middle that dye can pool in but not a true ulcer

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17
Q

What is rose bengal dye used for

A

Adheres to areas deficient in mucus e.g in dry eye

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18
Q

Where embryologically do the anterior structures in thee ey come from

A

Neural crest and mesenchyma

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19
Q

Where do the cornea and lens come from embryologically

A

From ectoderman placode

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20
Q

WHere do retina and ciliary body come from embryologically

A

optic vesicle; outpouching of midbrain

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21
Q

Glands in the eyelid/eyelid margin and what do they secrete
Zeiss, Moll, Meibomian

A

Zeiss secrete aqueous secretion
Moll secrete sebaceous
Meibomian glands made lipid component of tear film

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22
Q

Nerve supply to levator palpebrarum and implications of this

A

Trigeminal sympathetic supply; so in Horner’s syndrome get upper eyelid drooping (ptosis)

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23
Q

What does orbicularis oculi cause

A

Closing of the eyelid

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24
Q

Which species often have coloboma of the eyelid and where is it

A

Cats and snowleopards
Found laterally on the upper eyelid
- May also have optic disc coloboma

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25
Q

4 causes of entropion

A

1) Tarsal plate defect
2) Excess facial skin
3) Dropping upper lid
4) diamond eye

26
Q

What is the most common cause of entropion and how do we treat it

A

Tarsal plate defect
Seen in retrievers, cocker spaniels
Use Hotz-celcus procedure to remove an oval of skin

27
Q

How can we deal with entropion due to excess facial skin in puppies

A

Use temporary vertical mattress sutures to evert the eye; should resolve as animal grows

28
Q

How do deal with entropion caused by drooping upper lid e.g in Cocker spaniels

A

Do a stades procedure; remove lid and cilia

29
Q

What is a stades procedure

A

Make incision at lid margin and remove skin and lashes; then leave open to granulate
Used to correct eyelid drooping causing entropion

30
Q

How does the Hotz-celcus procedure work

A

Remove an elipse of tissue about 1mm from eyelid edge and suture up
- Used to correct entropion due to tarsal plate defect
Or can be used to correct diamond eye

31
Q

How do we estimate amount of skin to remove in a Hotz-celcus procedure

A

Pinch skin and outturn eyelid in an unsedated patient

32
Q

Which breeds is diamond eye part of the breed standard for

A

Bloodhound, St Bernard, Clumber spaniel

33
Q

What is diamond eye

A

Ectropion + entropion on the sloping lid edges

34
Q

What is a Wyman lateral canthoplasty

A

Involves suturing flaps of orbicularis oculi to correct diamond eye

35
Q

What is a potential sequelae to ectropion

A

Exposure keratitis

36
Q

How to correct ectropion

A

Wedge resection of excess lid
Or Khunt-Szymanowski procedure to involve lid splitting

37
Q

What type of tumours are commonly seen on dog eyelids

A

Benign
- Sebaceous adenoma, squamous papilloma, benign melanome, histocytoma

38
Q

What type of tumours are commonly seen on cat eyelids

A

Malignant; squamous cell carcomas

39
Q

What is distichiasis

A

Where an extra set of lid hairs comes from the Meibomian gland orifices at lid edge and cause ocular irritation

40
Q

Why should we not attempt to remove distichiasis hairs via sharp knife surgery on the lid margin itself

A

Get scarring of area which leads to corneal irritation and pathology

41
Q

What is trichiasis and what breed anatomy can lead to this

A

= where hairs growing in normal position are placed abnormally onto the cornea and cause irritation
- E.g dropping upper lid in old cockers (entropion)
- E.g nasal fold hairs in Pekinese etc
- E.g Ingrowing medial canthus hairs in brachycephalics

42
Q

What is chalazion

A

Lump on the eyelid due to blockage of the meibomiam gland (can occur due to meibomitis)

43
Q

What is juvenile cellulitis

A

where the whole lid becomes swollen due to an allergic reaction to normal staphylococci
- Need steroids +/- antibiotics to deal with it

44
Q

What type of suture should we use to repair lid trauma

A

6/0 vicryl
Figure of 8 knots

45
Q

Movement of the third eyelid

A

Moves across the eye when the globe is retracted by retractor bulbi
Protrudes both when eye retracted or protruding

46
Q

Things that might cause third eyelid protrusion

A
  • Retrobulbar space occupying lesion
  • Reduced retrobulbar muscle contraction after tranquilisation/tetanus/torovirus
  • Reduced orbital contents e.g dehydration, microphthalmia
  • enopththalmos from trauma, Horner’s syndrome, ocular pain
47
Q

Which breeds do we tend to see cherry eye and how do we correct it

A

Brachycephalics and Mastiffs
- Use pocket technique to correct it
- Could remove gland but bad idea since it controbutes 30% of tear film so risk of dry eye

48
Q

How are tears removed/flow out

A

Evaporation
Drainage through nasolacrimal system
Flow aided by orbicularis oculi squeezing on canailculi when blinking

49
Q

What is keratoconjunctivitis sicca

A

Dry eye
- insufficient tear production

50
Q

What would be an indication that KCS is due to a neurological defect

A

Also seeing a dry nose

51
Q

What can cause KCS

A

Neurological issues; ophthalmic branch of trigeminal or facial nerve
Iatrogenically from sulphonamides
Autoimmune; lymphocytic infiltrate into glands

52
Q

Complications that can arise from parotid duct transposition

A

Overproduction of tears
Duct can siccatrise and stop producing saliva

53
Q

Treatment for KCS

A

Cyclosporine (optimmun 0.2%), artificial tears, protecting gel, pilocarpine drops

54
Q

What would dogs with deficienct in the mucus component of the tear film present with and what is the cause

A

Chronic keratitis but NORMAL schirmer tear test
Due to infection or inflammation of the Meibomian gland; so get lipid deficiency and unstable tear film

55
Q

What congenital defect can cause insufficient tear drainage

A

Micropunctun or imperforate punctum

56
Q

WHy might we give adrenaline during surgery for imperforate puncta

A

To stop haemorrhage which could lead to fibrosis and scarring

57
Q

What is epiphora

A

Insufficient tear drainage

58
Q

What is dacryocystitis

A

Persistent mucopurulent discharge due to blockage of nasolacrimal duct with inflammation/infection

59
Q

Which breed has an issue with functional defects in an otherwise patent nasolacrimal duct

A

Poodles
- See as brown facial tear staining

60
Q

What procedure to do with globe prolapse

A

Canthotomy; cut lateral canthus and lift eyelids

61
Q

If there is an infectious cause of exophthalmos what symptoms will we see

A

Pain opening mouth
Pus coming out behing top last molar