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Ophthalmology > Ophthalmology Unit 1 > Flashcards

Ophthalmology Unit 1 Flashcards

1
Q

What part does the prefix blepharo- refer to

A

Lids

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2
Q

What part does the prefix kerato- refer to

A

Cornea

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3
Q

What part does the prefix hyp- refer to

A

Anterior chamber

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4
Q

What part does the prefix phaco- refer to

A

Lens

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5
Q

What part does the prefix hya- refer to

A

Vitreous

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6
Q

What is redness of the conjunctiva called

A

Hyperemia

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7
Q

What is edema of the conjunctiva called

A

Chemosis

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8
Q

What type of animals have an open (incomplete) orbit, an orbit that is only partially surrounded by bone
Which animals have an enclosed orbit

A

Pigs and carnivores (dogs and cats) are open
Horses, oxen, sheep, cattle, and goats are closed

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9
Q

Which muscles that move the eye are innervated by ocular nerve III (oculomotor)

A

Dorsal rectus, medial rectus, ventral rectus, and ventral (interior) oblique

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10
Q

Which muscles that move the eye are innervated by cranial nerve VI (abducens)

A

Lateral rectus muscle and retractor oculi (bulbi) muscle

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11
Q

What muscle that moves the eye is innervated by cranial nerve IV (trochlear)

A

Dorsal (superior) oblique

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12
Q

Which muscles rotate the eye medial and lateral and which ones pull the eye dorsal and ventral

A

Rotates medial- medial rectus
Rotates lateral- lateral rectus
Pulls dorsal- dorsal rectus
Pulls ventral- ventral rectus

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13
Q

Which muscles pull the eye medial and lateral

A

The dorsal (superior) oblique pulls the eye medial and the ventral (inferiors) oblique pulls the eye lateral

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14
Q

What muscle is the only one to contribute to closure of the lid and what nerve controls it

A

Orbicularis oculi, cranial nerve VII (facial)

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15
Q

What muscle elevates the upper lid and what cranial nerve innervates it

A

Levator palpebral superioris, cranial nerve III (occulomotor)

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16
Q

What smooth muscle keeps the eyelids topically retracted

A

Muller’s muscle

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17
Q

What cranial nerves provide sensory input to the eyelids

A

Cranial nerve V (trigeminal) maxillary division for lateral lids and ophthalmic division for medial and ventral lids

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18
Q

T/F movement of the third eyelid is indirect

A

True

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19
Q

What is the conjunctiva lining the eyelids called? How about the conjunctiva covering the globe

A

Palpebral lines the eyelids and bulbar covers the globe

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20
Q

What is the junction or the blind sac of the palpebral and bulbar conjunctiva called (aka where there is a pocket created under the eyelids)

A

The fornix (cul de sac)

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21
Q

What are the three components of the precorneal tear film and the functions

A

Lipid- limits evaporation, serous- water part that moistens, mucous- keeps the tears on the eye

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22
Q

What feeds into the nasolacrimal duct

A

The lacrimal punctum which turns into the lacrimal canaliculus to enter the nasolacrimal duct

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23
Q

What glands form the lipid tear layer

A

The meiobomian gland and the glands of zeis

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24
Q

What glands form the serous layer of the tear film

A

The lacrimal gland and the gland of the third eyelid

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25
Q

What forms the mucous layer of the tear film

A

The goblet cells of the conjunctiva

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26
Q

What are the functions of the precorneal tear film

A

Maintaining an optically uniform surface, removing foreign material and debris, providing nourishment to the cornea, preventing infection

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27
Q

Which chamber is between the cornea and iris

A

The anterior chamber

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28
Q

Which chamber is between the iris and the lens

A

Posterior chamber

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29
Q

What makes up the anterior and posterior segments

A

The anterior segment is the front of the eye with the cornea, lens, iris, ciliary body, anterior and posterior chambers, etc.
The posterior segments contains the vitreous body in the vitreous chamber, the optic disk, retina, etc.

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30
Q

The globe is composed of what three layers and what is contained within these layers

A

Fibrous tunic- outer layer- cornea and sclera
Uvea- middle layer- iris, ciliary body, choroid
Nervous- inner layer/ central layer- retina and optic nerve

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31
Q

What is considered the internal media of the eye

A

Lens, aqueous, vitreous

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32
Q

Visually, the cornea is _____ when compared to the sclera which is _____

A

Visually, the cornea is transparent when compared to the sclera which is opaque

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33
Q

Name the layers of the cornea in order

A

Epithelium, basement membrane, bowman’s layer (in cows, primates, and birds), stroma, Descemet’s membrane (with a basal lamina/ basement membrane), and posterior epithelium (endothelium)

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34
Q

What makes up 90% of the cornea

A

The stroma

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35
Q

What is an important feature of the cornea in how it gets its nutrients

A

It is avascular so it must get its metabolic needs from tears, aqueous humor, and limbal capillaries

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36
Q

70% of refraction occurs where

A

In the cornea

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37
Q

What makes up the sclera

A

Elastic fibers and collagen fibers

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38
Q

What is the area called where the cornea and sclera meet

A

The limbus

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39
Q

People often compare the Irises function to that of a

A

Camera

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40
Q

What are the zones of the iris starting at the zone closest to the pupil

A

Pupillary border, central pupillary zone, collarette, peripheral ciliary zone

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41
Q

What is the largest component of the anterior uvea

A

The ciliary body

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42
Q

What produces aqueous humor and how does aqueous humor drain and what does it provide

A

The ciliary process on the ciliary body, it drains through the iridocorneal angle, and provides nourishment and removes waste

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43
Q

Where is the blood aqueous barrier

A

In the nonpigemented epithelium of the ciliary body

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44
Q

What makes up most of the mass of the ciliary body and what does this mean for function

A

Most of the mass is muscular and the function is accommodation through movement of the zonules which change the shape of the lens capsule and lens

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45
Q

What is the function of the choroid

A

To provide nutrition to the retina

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46
Q

What are the four layers of the choroid

A

Choriocapillaris (thin layer of capillaries), tapetum, medium sized vessel layer (choroidal vein), suprachoroidea (elastic connective tissue that is the transition between the choroid and the sclera)

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47
Q

What is the second most powerful refractive surface of the eye and what is its function

A

The lens, it focuses light onto the retina through accommodation

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48
Q

What has the highest protein content compared to any other organ in the body

A

The lens

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49
Q

Immunology what is the lens

A

It is seen as a foreign antigen

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50
Q

What is the lens capsule

A

A semipermeable membrane where the zonules attach, keeps the lens separate from the body

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51
Q

What is the site of most of the energy production of the lens

A

The anterior epithelium, uses anaerobic glycolysis (glucose) for energy

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52
Q

What happens to the lens as we age

A

It adds more protein to it every year to it gets larger and less mailable to accommodation which makes it harder to see through it

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53
Q

What are the layers of the lens

A

The capsule, cortex, and nucleus with adult, fetal, and embryonic layers

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54
Q

What makes up 2/3 of the volume of the globe

A

The vitreous, which is 98% water

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55
Q

Other than maintaining the shape of the eye what are other functions of the vitreous

A

It maintains the normal position of the retina and also functions to transmit light

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56
Q

What are the two components of the nervous tunic

A

Retina and optic nerve

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57
Q

How many layers is the retina made of

A

10, 9 neurosensory layers (neuroretina) and a single retinal pigment epithelium

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58
Q

What are the three functions of the retinal pigmented epithelium

A

It is the location of the blood retinal barrier, it transports retinol, and does phagocytosis and degeneration of the photoreceptor disc

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59
Q

In the synaptic body of the photoreceptor cell what is located there

A

Mitochondria

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60
Q

What does the outer segment of the photoreceptor cell contain

A

The discs and photopigments

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61
Q

What are the different photopigments and their functions

A

Rods- red, green, blue wavelengths (color)
Cones- Rhodopsin

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62
Q

Where does phototransduction take place and what is that

A

It is the conversion of light energy into electrical energy and it takes place in the outer segment

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63
Q

What is in the ganglion cell layer

A

The nuclei of the retinal ganglion cells

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64
Q

What is the in the nerve fiber layer

A

The axons of the ganglion cells

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65
Q

What makes up the orbital portion of the optic nerve and what is it considered to be

A

Considered to be a nerve fiber tract, the orbital portion of the optic nerve runs from the lamina cribrosa to the optic foramen

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66
Q

At what part (what section) of the nerve do the optic nerve fibers cross

A

The intracranial portion (from the optic canal to the optic chiasm)

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67
Q

What is the synapse of the optic tracts

A

The lateral geniculate body

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68
Q

What coordinates the orientation to visual stimuli and is sensitive to horizontal stimulus movement

A

The rostral colliculus

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69
Q

What is the efferent tract for parasympathetic oculi motor nuclei

A

The pretectal nucleus

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70
Q

What is the ocular fundus composed of

A

The retina, retinal vessels, optic disc, and the parts of the choroid and sclera that can be seen through the retina

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71
Q

What is a holangiotic retinal vascular structure and what animals have this

A

When there are blood vessels that cover the whole retina, most mammals have this

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72
Q

What is a merangiotic retinal vascular structure and what animals have this

A

The blood vessels are only on the meridian, lagomorphs (rabbits) have this

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73
Q

What is an anangiotic retinal vascular structure and what animals have this

A

One little area with the blood vesssles, birds have this

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74
Q

What is a panurangiotic retinal vascular structure and what animals have this

A

A circular area of blood vessels that cover part of the retina, horses have this

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75
Q

Describe the layers and media that make up the globe

A

Fibrous layer- cornea and sclera
Vascular/ pigmented layer- uveal tract- iris, ciliary body, choroid
Nervous layer- retina
Clear ocular media- tear film, aqueous humor, lens, vitreous humor

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76
Q

What is the adnexa

A

The eyelids, conjunctiva (palpebral and bulbar), and the nasolacrimal system

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77
Q

What makes up the orbit

A

The bones, extraocular membrane, vessels, and glands

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78
Q

What are the components of the ophthalmic exam

A

Neuro-ophthalmic exam- PLR, palpebral reflexes, vision, ocular motility
Exam proper- orbits, eyelids, globes
Ancillary tests- Sherman tear test, fluorescein stain, intraocular pressure measurement

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79
Q

What are important considerations for the history

A

Signalment- age, sex, species, breed, coat color,
Presenting complaint- change in vision? Pain? Discharge? Color or opacity change? How long, any treatment, any change?
Previous ophthalmic concerns or systemic signs
Medications
Travel history and exposure
Other animals effected?

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80
Q

What is some basic equipment for the ophthalmic exam

A

Finoff transilluminator
Slit beam
Ophthalmoscope
Indirect lens
Magnification

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81
Q

What is the use for proparacaine and a way it should never be used?

A

It is a topical anesthetic to cause short-acting but rapid ocular surface anesthesia to help with some procedures and cytologies
Never use for therapeutic use!

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82
Q

What should you evaluate before you use proparacaine (or any drops really)

A

Evaluate tear film quality and quantity

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83
Q

What is the mechanism of action of tropicamide and its use

A

It is a parasympatholytic that causes rapid short acting pupil dilation, used for a more thorough lens and fundic exam

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84
Q

What is tropicamide contraindicated for

A

Glaucoma

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85
Q

What should you evaluate before administering tropicamide

A

PLRs and iris tissue

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86
Q

What should you warn owners of if they are going to be present when you administer tropicamide

A

That it causes drooling because of its bitter taste
Also causes light sensitivity

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87
Q

How should you start your ophthalmic exam

A

Watching the animal from a distance and seeing how it visually tracts, looking at facial symmetry, the size and shape of the globe and orbit, the eyelid position, any discharge, the pupil size and shape

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88
Q

What nerve must you block in large animals to cause eyelid akinesia so you can do an ophthalmic exam

A

Cranial nerve VII (facial)

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89
Q

What are the afferent and efferent neurons stimulated by the pupillary light reflex and what is the effector muscle

A

Afferent- CN II (optic)
Efferent- CN III (oculomotor)
Effector muscle- Iris sphincter muscle

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90
Q

What are the afferent, and efferent neurons stimulated by the dazzle reflex and what is the effector muscle

A

Afferent- CN II (optic)
Efferent- CN VII (facial)
Effector muscle- orbicularis oculi muscle

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91
Q

What are the afferent and efferent neurons stimulated by the menace response and what is the effector muscle

A

Afferent- CN II (optic)
Efferent- CN VII (facial)
Effector muscle- orbicularis oculi muscle

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92
Q

What are the afferent and efferent neurons stimulated by the palpebral reflex and what is the effector muscle

A

Afferent- CN V (trigeminal- ophthalmic and maxillary branches)
Efferent- CN VII (facial)
Effector muscle- orbicularis oculi muscle

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93
Q

What are the afferent and efferent neurons stimulated by the corneal blink reflex and what is the effector muscle

A

Afferent- CN V (trigeminal- ophthalmic branch)
Efferent- CN VII (facial)
Effector muscle- orbicularis oculi muscle

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94
Q

What are the afferent and efferent neurons stimulated by the doll’s eye reflex and what is the effector muscle

A

Afferent- CN VIII (vestibulocochlear)
Efferent- CN III, IV, VI (oculomotor, trochlear, abducens)
Effector muscle- extraocular muscle

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95
Q

In order to have a direct PLR, what must all be working in the stimulated eye

A

Requires the retina (photoreceptors), cranial nerve II (afferent) and III (efferent), and iris muscle to all be working

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96
Q

What pathway must be functioning in the eye not being stimulated in order to have an indirect PLR

A

The efferent pathway of the non-stimulated eye (CN III and iris muscle) and a functioning afferent pathway in the stimulated eye

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97
Q

Is PLR a vision test and give an example why or why not

A

No it isn’t, a blind eye from cataracts will have a normal PLR, also a seeing eye may not have a PLR if it has severe iris atrophy and the pupil is always dilated

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98
Q

A dog has retinal or optic nerve disease, what will its PLR look like

A

This is affecting the afferent pathway so the diseased eye will not have a PLR and neither will the other eye (no consensual). When the contralateral eye is stimulated the diseased eye will have a PLR

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99
Q

A dog has cranial nerve III or iris disease, what will its PLR look like

A

This is affecting the efferent pathway so the diseased eye will not have a PLR (absent direct PLR) but the contralateral eye will have a PLR. However when the light is shone in the contralateral eye the diseased eye will not have a consensual response

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100
Q

Lesions affecting the afferent optic tract typically present as what

A

Visual impairment/ blindness

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101
Q

Lesions affecting the efferent optic tract typically present as what

A

Normal vision but iris atrophy

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102
Q

In terms of assessing vision, when is the PLR useful

A

When you are assessing to see if it is going to return. If there is an absent consensual PLR from the affected eye to the contralateral eye there is low potential for restoration of vision

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103
Q

Which visual reflex is a learned response so it won’t always be present in young animals

A

The menace response

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104
Q

In the neural pathways for the visual reflexes, all but one use the same interneuron. What is this interneuron and which one does not use that one and what does it use

A

They all use the sub-cortical interneuron except menace which uses the cortex and cerebellum

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105
Q

Other than examining the eye during an eye exam, what other area should you examine that isn’t the eye/orbit/eyelids and why

A

You should look inside the mouth at the pytergopalatine fossa (caudal to the last molar) because oral disease/ foreign bodies can enter the orbit here

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106
Q

How do you assess the different parts of the third eyelid

A

You can retropulse the globe to assess the palpebral surface and you can use a topical anesthetic and manual retraction to evaluate the bulbar aspect

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107
Q

When preforming retroillumination in a patient what should you look for/at

A

Assess facial and pupil symmetry and assess the clear ocular media (visual axis) for opacities

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108
Q

Why is transillumination helpful

A

You can shine light and observe it as it passes through transparent and translucent ocular structures

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109
Q

Describe the parts of a purkinje image

A

The first white line is the tear film/ cornea, behind it is the anterior chamber which is normally black, the beginning of the lens is the anterior lens capsule, this is followed by the “smokey” lens, then the posterior lens capsule

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110
Q

In terms of lesion localization, which covers which the anterior structures or the posterior ones

A

The anterior structures cover the posterior ones

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111
Q

If an object is seen in front of the iris where must it be

A

In the anterior chamber or the cornea

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112
Q

How can you tell where an object is in the eye based on how it moves

A

Lesions anterior to the center of the lens move in the same direction as the front of the eye, lesions posterior to the center of the lens move in opposite direction as front of the eye

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113
Q

What are the steps of examining the cornea

A
  1. Retroillumination
  2. Exam with naked eye
  3. Diffuse and transillumination and maybe magnification
  4. Focused (slit) bean
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114
Q

How do you examine the anterior chamber

A
  1. Retroillumination
  2. Diffuse and trans-illumination
  3. Focused (slit) beam
    Compare to other eye
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115
Q

How do you examine the lens

A
  1. Retroillumination- look for backlit opacities
  2. Diffuse and trans-illumination
  3. Focused (slit) beam to determine depth in lens
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116
Q

Where are cataracts located

A

In the lens

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117
Q

When preforming direct ophthalmoscopy what eye do you use to view the left (OS) and right (OD) eyes

A

You use your right eye to view their right eye and you use your left eye to view their left

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118
Q

If an object is located on the retina at what dioptric strength when using a direct ophthalmoscope will the object be in focus, what about if the object is in front or behind the retina

A

If the object is on the retina it will be in focus at dioptric strength 0, if it is in front of the retina it will be + D, and behind the retina is - D

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119
Q

T/F the smaller the eye the less magnified it is by the direct ophthalmoscope

A

False, smaller eyes are more magnified

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120
Q

What is a good tool for screening the fundus

A

Monocular indirect ophthalmoscope (or binocular)

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121
Q

What are the benefits of direct ophthalmoscopy vs. indirect

A

Direct is easier to use and is a real, upright image (not inverted and reversed), it can give high magnification which is helpful for closer examination of the optic nerve or lesions

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122
Q

What does the schirmer tear test measure and what is the normal values for the test

A

The aqueous (water) component of the tear film, dogs are normally > or equal to 15mm, and <10 is abnormal, cats are variable due to sympathetic tone (not really used much with cats)

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123
Q

What are all the uses for the fluorescein stain

A

Detect defects in the ocular surface (epithelium)
Access tear film health/deficiencies
Assess the patency of the nasolacrimal tear drainage (Jones test)
Detect leakage via ocular defects (Seidel test)

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124
Q

What is specifically being stained by fluorescein stain

A

The stroma of the cornea (b/c hydrophilic)

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125
Q

If an animal is positive for the Jones test where will the fluorescein stain appear

A

The nostrils

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126
Q

What are the normal values for tonometry (intraocular pressure) and what does a high and low IOP signify

A

15-25mmHg is normal
High can be a sign of glaucoma, low can be a sign of uveitis
OR a difference between the eyes > 5-10mmHg can suggest an issue

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127
Q

What is the difference between how the tono-pen and tono-vet work

A

The tono-pen flattens the eye (applanation) and often requires topical anesthesia
The tono-vet uses induction-impact/rebound and doesn’t require topical anesthesia

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128
Q

What are some patient related factors that impact IOP

A

Age- decreases with age
Excitement/ stress- increases
Breed

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129
Q

What does the rose bengal stain do

A

It detects devitalized epithelial cells and/or tear film (mucin) deficiency, more sensitive than fluorescein which detects epithelial loss/defect

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130
Q

What are the ocular barriers to drugs

A

The tear film (dilutes)
The hydrophobic epithelium and hydrophilic stroma of the cornea
The blood eye barrier

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131
Q

What should be your targets if you are choosing to give a topical eye medication

A

The ocular surface to posterior lens capsule

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132
Q

When is it best to use systemic medications for eyes

A

When you are trying to target the lids, orbit, posterior segment, or if there is a perforated globe

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133
Q

What does the blood eye barrier cover

A

the endothelial cells of the iris blood vessels and epithelial cells of the ciliary body

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134
Q

give an example of when drugs can get into the uvea by crossing the blood brain barrier

A

uveitis- the barrier breaks down because of inflammation

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135
Q

What type of drug is best to use to get to the choroid

A

systemic, there is a blood retinal barrier

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136
Q

Where to the topical drugs usually go

A

most are onto the face, some go systemically by absorption through the conjunctiva or down the nasolacrimal duct, lastly some get into the aqueous humor by transcorneal absorption

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137
Q

if you are having to give different medications, how far spaced out should you give solutions and ointments

A

solutions should be spread out every 5 minutes and ointments every 30 minutes

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138
Q

what type of drugs cause dilation of the eye (mydriasis)

A

parasympatholytics (anticholinergic) and sympathomimetics

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139
Q

what type of drugs cause constriction of the eye (miosis)

A

parasympathomimetics (cholinergics) and sympatholytics

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140
Q

Give two examples of topical mydriatics that are parasympatholytics and how do they differ

A

1% Tropicamide- short acting and no pain relief and 1% Atropine- long acting and pain relief

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141
Q

Give an example of a topical mydriatic that is sympathomimetic and what are some side effects

A

phenylephrine- it can have some serious systemic effects- increase heart rate and cause local vasoconstriction, activates dilator muscles

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142
Q

what drug is often given pre-op for a cataract patient to dilate the eye

A

phenylephrine

143
Q

What drug is often used for reflex uveitis or directly for uveitis pain

A

Atropine

144
Q

What drug is a topical anesthetic but you can’t use it as a pain relief therapy because it dries, causes ulceration, delays healing, up-regulates pain receptors

A

Proparacaine HCL or tetracaine

145
Q

Which topical antibiotics can be used for cat conjunctivitis

A

chloramphenicol and tetracyclines

146
Q

which topical antibiotic is good for gram positive organisms

A

cefazolin

147
Q

Which topical antibiotic is good for rods

A

aminoglycosides- neomycin, gentamicin or tobramycin; ciprofloxacin,

148
Q

Which topical antibiotic is good for cocci

A

triple antibiotic or chloramphenicol

149
Q

What is the “big gun” topical antibiotic that is used in septic keratitis with rods and can get gram negatives and aerobic positives

A

second generation fluoroquinolones- ciprofloxacin, ofloxacin, levofloxacin

150
Q

which antibiotic is reserved for multi drug resistant infections and can get gram negative and positives well

A

4th generation fluoroquinolones- moxifloxacin, gatifloxacin

151
Q

What are antiproteases and how are they used

A

It is plasma or serum given as an eye drop to treat melting corneal ulcers

152
Q

how often would you give topical antibiotics for prophylactic therapy? How about septic conjunctivitis? How about septic keratitis?

A

prophylactic- 2-3 times a day
septic conjunctivitis- 3-4 times a day
septic keratitis- every 1-2 hours

153
Q

corneal infiltrate is a hallmark of what

A

an infection

154
Q

What animal is most likely to get a corneal fungal infection

A

a horse

155
Q

What are the topical anti-fungals used in eyes

A

natamycin, itraconazole, miconazole, voriconazole

156
Q

What are the three topical anti-virals used in eyes

A

trifluridine (most effective and expensive), Idoxuridine, Cidofovir

157
Q

What are the two systemic antivirals often used in cats with herpes

A

L-lysine and famcyclovir

158
Q

dexamethasone is often in combo with what

A

Neomycin and polymyxin B (NeoPoly Dex)- often cheaper than just dexamethasone too

159
Q

What are the side effects of a topical steroid in the eye

A

They can delay corneal wound healing so NEVER use if the cornea is ulcerated
They can reactivate herpes
Lipid deposits in cornea
Iatrogenic Cushing’s

160
Q

Flurbiprofen sodium Ocufen, Diclofenac Voltaren, Bromfenac Xibrom, and Keterolan Acular are all what

A

topical eye NSAIDS

161
Q

which is better for immune-mediated inflammation and which is better for traumatic inflammation, steroids or NSAIDS

A

steroids are better for immune mediated and NSAIDS are better for traumatic inflammation

162
Q

T/F you can give NSAIDS and steroids together topically

A

true

163
Q

What are some challenges when treating glaucoma

A

there are huge differences between species and even between individuals with how they respond to the drug

164
Q

What characteristics must a drug have to penetrate the cornea

A

The drug must be lipophilic (to diffuse through cells) and hydrophilic (diffuse between cells)

165
Q

When is mannitol used

A

In pre-op for lens luxation

166
Q

what is the prostaglandin analog (PGF2alpha agonist) used in angle closure glaucoma cases

A

latanoprost (Xalatan)

167
Q

How does latanoprost (Xalatan) work and in what species does it work

A

It binds to the FP (prostaglandin F) receptor which increases uveoscleral outflow (drains aqueous humor) to decrease IOP, causes miosis, and reduces aqueous production (in dogs)
only works in dogs and humans to reduce IOP

168
Q

When is it contraindicated to use latanoprost (Xalatan)

A

in uveitis and anterior lens luxation (and probably in cats with glaucoma cause it doesn’t reduce IOP in them)

169
Q

What is oral methazolamide or dichlorphenamide (Trusopt, Cosopt, Azopt)

A

carbonic anhydrase inhibitors

170
Q

How do carbonic anhydrase inhibitors help with glaucoma

A

By inhibiting carbonic anhydrase the aqueous humor is decreased

171
Q

How do cholinergics work

A

they increase the aqueous humor outflow by causing miosis (contracting the longitudinal ciliary muscle) which in turn reopens the angle/ breaks the pupil block

172
Q

what do beta-adrenergic blockers do and what causes are they used in

A

they decrease the aqueous production and may increase the outflow (miosis) but are a 3rd choice in secondary glaucomas or as a prophylactic

173
Q

What are two causes of Keratoconjunctivitis Sicca (KCS)

A

quantitative- low schirmer tear test
qualitative- rapid tear break up time

174
Q

What are the two t-cell modulators (tear stimulants) used for Keratoconjunctivitis Sicca (KCS) treatment and the differences

A

Cyclosporine A (FDA approved) and Tacrolimus (not approved cause possible carcinogen, but works just as well if not better)

175
Q

What specific type of Keratoconjunctivitis Sicca (KCS) can a cholinergic be used for

A

neurogenic KCS, replaces the parasympathetic neurotransmitter

176
Q

Which drugs are best to use as artificial tears for a mucin deficiency and how do they work

A

cyclosporine (stimulates), polyvinylpyrrolidone (mimics), Methylcelluloses (mimics)

177
Q

Which drugs are best to use as artificial tears for a lipid deficiency (blepharitis)

A

Refresh Endura or soothe (oil based), sodium hyaluronate, warm compresses

178
Q

What would you use if an eye had an erosion secondary to corneal edema

A

sodium chloride- suck out that fluid!

179
Q

what is the magic drug that will dissolve a cataract?

A

there is none! save your money for surgery

180
Q

What are the common bugs that cause feline conjunctivitis

A

chlamydia, herpes, mycoplasma

181
Q

what are four topical antibiotics used to treat feline conjunctivitis and how often should you give the drugs

A

tetracyclines, erythromycin, ciprofloxacin, chloramphenicol, treat frequently! BID-TID

182
Q

If you had a dog with a corneal erosion and it wasn’t infected what may you start prophylactically?

A

Neomycin (aminoglycoside)/polymyxin often used with bacitracin added to ointments or gramicidin added to solutions
gram neg and pos coverage

183
Q

what is a good broad spectrum treatment for infected corneal ulcers

A

Aminoglycoside (gentamicin, tobramycin, neomycin) OR Fluoroquinolones (ciprofloxacin, ofloxacin, etc.)
AND
cefazolin

184
Q

What muscle is responsible for “squeezing” and pushing the globe forward into a normal position, it relaxes when sleeping

A

the smooth muscle cone

185
Q

What type of tone causes the smooth muscle cone to push the eye forward

A

sympathetic

186
Q

What are some basic/ beginning parts of the orbital examination (hint there are six ones I have listed and all of them just involve your hands and eyes, no real special equipment)

A

Looking at facial, orbital, and globe symmetry- look from top!
Orbital rim palpation
Retropulsion of the globes- can it be done easily?
ocular motility- doll’s eye reflex, positions of base
nasal airflow
oral exam

187
Q

When are radiographs helpful in ophthalmology (You can’t see eyeballs on an X-ray what the heck??)

A

they can be helpful for examining the orbit and surrounding structures like the sinuses, maxilla and mandible, and teeth!

188
Q

What are four differentials for enophthalmos (globe recessed in orbit)

A

A lesion anterior to the globe that is space-occupying
A decrease in orbital volume (ex. dehydration, emaciation, etc.)
Pain
Lack of orbital smooth muscle tone (Horner’s syndrome)

189
Q

What are two abnormalities you may need to differentiate from enophthalmos and how would you do this

A

atrophy- phthisis bulbi
microphthalmos- congenitally small globe
you look at the corneal diameter- with enophthalmos the diameter is equal and with microphthalmos or phthisis bulbi it is decreased

190
Q

what commonly causes exophthalmos

A

a space-occupying lesion within the orbit

191
Q

what other clinical signs do you often see with exophthalmos

A

lagophthalmos (inability to blink)
strabismus (deviation of the globe)
exposure keratitis (inflammation of cornea)
increased scleral show
sometimes third eyelid elevation

192
Q

what do you need to differentiate exophthalmos from and how do you do that

A

differentiate from buphthalmos (enlarged globe) by assessing from above, assessing corneal diameter (equal with exophthalmos and increased with buphthalmos), and if there is resistance to retropulsion (exophthalmos will resist)

193
Q

What are four clinical signs of orbital disease

A

third eyelid elevation
strabismus
epiphora (tearing)- due to obstruction of nasal lacrimal duct
Vascular congestion in conjunctiva, episclera, or retina

194
Q

what is microphthalmos associated with (other than a small globe obviously)

A

a small palpebral tissue and orbit and often there will be multiple congenital ocular deficiencies, also associated with merle coat color

195
Q

What is it called when there is a single eye fused at the midline

A

cyclopia/synophthalmos

196
Q

siamese cats often have what congenital abnormality

A

convergent (inward) strabismus (esotropia)

197
Q

brachycephalic dogs often have what congenital abnormality

A

divergent (outward) strabismus (exotropia)

198
Q

what causes Horner’s syndrome

A

loss of sympathetic innervation to the orbit

199
Q

what are symptoms of Horner’s in a dog? How does a horse and cow vary

A

Dog
-ptosis (drooping of upper eyelid)
-miosis (small pupil)
-enophthalmos (recessed globe)
-nicitating membrane/ third eyelid protrusion
Horse- in addition to dog ones, ipsilateral sweating and vascular hyperemia of face
Cow- same as dog plus a ipsilateral dry nasal planum

200
Q

describe the sympathetic innervation to the orbit and know that a lesion along any of these structures can cause Horner’s syndrome

A

Central neuron- hypothalamus to T1-T3 (or T4)
Preganglion neuron- T1-T4 to sympathetic trunk
Autonomic ganglion- cranial cervical ganglion
Postganglionic neuron- CN V branches to orbital structures

201
Q

Why does ptosis (drooping of upper eyelid) occur with Horner’s

A

mueller’s muscle denervation

202
Q

Why does miosis occur with Horner’s (muscle effected)

A

denervation of iris dilator muscle

203
Q

Why does enophthalmous occur with Horner’s

A

denervation of orbitalis muscle/ smooth muscle cone

204
Q

Why is there sweating and hyperemia of the face with Horner’s

A

vasodilation (loss of sympathetic vasoconstriction)

205
Q

What is the most common cause of Horner’s in dogs

A

idiopathic

206
Q

How do you localize the lesion and confirm the diagnosis of Horner’s

A

phenylephrine- dilute will localize the lesion to post-ganglionic (if it resolves the symptoms), and 10% will confirm the diagnosis

207
Q

What is phthisis bulbi (atrophy of globe) secondary to

A

severe/chronic inflammation, glaucoma- damage to ciliary body decreases and eventually stops production of aqueous humor

208
Q

A dog presents with what appears to be orbital cellulitis or an abscess, what are some clinical signs you may see

A

acute onset, nictitans protrusion, usually unilateral exophalmus, resistance to retropulsion, pain upon opening of the mouth, and others

209
Q

How would you drain an orbital access

A

general anesthesia and create a stab incision in the pterygopalatine fossa- insert hemostats and open, do not close!

210
Q

what orbital disease are Goldens overrepresented for

A

extraocular polymyositis (swelling of extra ocular muscles)

211
Q

What disease can be immune-mediated and makes dogs look “stressed” (bilateral exophthalmos)

A

extraocular polymyositis (swelling of extra ocular muscles)

212
Q

which immune mediated disease are German shepherds and Weimaraners overrepresented that can cause blindness, bilateral exophthalmos, pain with opening the mouth

A

Masticatory/eosinophilic myositis

213
Q

T/F orbital neoplasia is usually benign

A

false

214
Q

What causes of exophthalmos are not painful

A

neoplasia and a cyst/mucocele

215
Q

How could you tell apart an exophthalmos caused by an abscess vs. a myositis

A

accesses are usually unilateral and myositis is usually bilateral exophthalmos, but both are acute and can cause pain, fever, and anorexia

216
Q

Proptosis is exophthalmos with what

A

entrapment of the eyelids behind the globe equator

217
Q

A BDLD presents to your clinic with a proptosed eye, what is important to do while you evaluate the patient

A

keep the eye lubricated

218
Q

Other than a lack of PLR, what is another bad sign with a proptosed eye

A

hyphema (pooling of blood in anterior chamber)

219
Q

What rule of thumb should you use when presented with a proptosed eye in terms of enucleation

A

If in doubt, replace. You can always remove it later.

220
Q

What has a better prognosis for their proptosed eye, a bulldog or a golden

A

a bulldog, brachycephalic breeds have a better prognosis!

221
Q

T/F being a cat or a horse is a negative prognostic indicator for successful replacement of a proptosed eye

A

true

222
Q

What is the rule of thumb for the number of extraoccular muscles avulsed with a proptosed eye and it being a negative prognostic factor

A

more than 3

223
Q

what type of sutures are used in a proptosed eye surgery to preform the tarsorrhapy (temporary surgical closure of the eyelids)

A

horizontal mattress

224
Q

what are possible sequelae to proptosis

A

corneal ulceration
blindness (20% K9 regain vision and 100% of felines will be blind)
Strabismus (often lateral)
KCS
lagophthalmos and exposure keratitis

225
Q

What is an enucleation defined as and give an example of when it is used

A

removal of just the globe, lid margins, conjunctiva, and third eye lid
used for treatment of glaucoma or perforation of the globe

226
Q

What is an exenteration defined as and give an example of when it is used

A

removal of globe and orbital contents
used for neoplasia or infection beyond sclera

227
Q

What is an evisceration defined as and give an example of when it is NOT used

A

removal of the intraocular contents which leaves a corneal shell where an implant can go
contraindicated for intraocular neoplasia or infection

228
Q

When blinking what eyelid moves the most

A

The upper eyelid

229
Q

Where are the ducts of the mebomian glands

A

On the lid margin

230
Q

When do eyes usually open after birth and if they don’t what is it called

A

10-15 days, ankyloblepharon is delayed or incomplete opening

231
Q

What is it called when there is eyelid agenesis and what species is it most common in

A

Coloboma, more common in cats

232
Q

What is euryblepharon and what species and clinical signs is it associated with
What syndrome is it also called

A

Macroblepharon, abnormally large palpebral fissure, associated with brachycephalic breeds and lagophthalmos (can’t fully blink) and tear film abnormalities- leads to corneal pigmentation, keratitis, and ulceration
Aka ocular brachycephalic syndrome

233
Q

What occurs with an entropion

A

Inward rolling of all or part of the eyelid margin and the hair rubs against the conjunctiva and cornea and can cause ulcers, pigmentation, and self-trauma

234
Q

What is primary vs. secondary entropion

A

Primary- congenitally long or lax lids, heavy brown folds
Secondary- pain/spastic or cicatricial from scarring

235
Q

How can you test to see in entropion is primary or secondary

A

Apply a topical anesthetic to the eye and see if it goes away, if so probably secondary

236
Q

What approach may you take to fix an entropion in a puppy vs. an older dog

A

In a puppy you may be able to use a horizontal mattress suture to tack the eyelid up temporarily
In an older dog you may need to use the Hotz-Celsus surgical repair (remove a strip of skin/muscle and close with a simple interrupted) or/and lateral canthoplasty (good for excessive lid length to remake lateral canthus

237
Q

T/F with a Hotz-Celsus entropion repair you should always take a little bit more than you measure just to be sure it actually fixes it

A

False! You should actually err on the lower side of skin removal

238
Q

what is ectropion

A

outward rolling of lid causing exposure of conjunctival tissue, and sometimes causing lagophthalmos (incomplete lid closure)

239
Q

is ectropion a common thing to fix

A

no, in fact it is desirable in some breeds. Only fix if there is ongoing conjunctivitis

240
Q

what is it called when you have a combined ect/entropion and what does it often look like

A

diamond eye, the entropion is on the sides (temporal and nasal) and then that causes an ectropion in the middle

241
Q

What is distichia/ distichiasis

A

there are additional eyelashes coming from metaplastic meibomian glands (undifferentiated meibomian tissue) so they grow down and into the eye, may have one or many per opening

242
Q

What is Trichiasis

A

eyelashes (cilia) that are in the right place but they are growing down and directed toward the cornea

243
Q

What is an ectopic/ aberrant cilia

A

an eyelash (cilia) that grows through to the underside of the eyelid (it grows straight down and through the conjunctiva)

244
Q

what is trichomegaly

A

long but normal eyelashes but they are so long they rub on the cornea

245
Q

what breeds are predisposed to distichia

A

cocker spaniels, English bulldog, shetland sheepdog, poodles

246
Q

what is the treatment for distichia

A

there isn’t a perfect one but cryotherapy is most common (but may kill meibomian glands)

247
Q

T/F ectopic cilia is a variation of distichia

A

true

248
Q

what are common symptoms of issues with the cilia

A

blepharospasm, conjunctivitis, keratitis, corneal ulceration

249
Q

what is the treatment for ectopic cilia

A

surgical excision and you must make sure you excise them all because there can be nests of hair

250
Q

Trichiasis can be primary or secondary, what would be an example of a treatment for a primary cause and a secondary cause

A

primary- grooming to cut the hair short enough from the eye
secondary- removal of nasal folds or hetz-celsus to remove skin folds that are pushing the hair into the eye

251
Q

What is important regarding eyelid trauma

A

it is well vascularized so large defects often heal well, so you should always try to put it back together and not cut it off. The most important thing is accurate position of eyelid margins

252
Q

what are the two types of malignant eyelid neoplasms in dogs (there are also many benign neoplasms- in fact most are benign, 85%)

A

mast cell and squamous cell

253
Q

How should you excise an eyelid neoplasm

A

take 1/3 to 1/4 of the eyelid involvement using a full thickness wedge resection or 4-sided excision

254
Q

what is important when removing eyelid tumors

A

that the lid margin comes together perfectly

255
Q

other than surgical removal what is another approach for removing eyelid neoplasms and what are advantages and disadvantages

A

debulk and cryotherapy- it is cheaper but more likely to need repeating and can cause depigmentation

256
Q

Are cat eyelid neoplasms more likely to be malignant

A

yes and they are locally invasive

257
Q

What is the most common eyelid neoplasm in a cat

A

squamous cell carcinoma

258
Q

A cat comes to you because the owner has noticed a weird grey mark next to its eye. What is this and what should you do

A

This is an apocrine hidrocystoma. You can remove it surgically or with cryotherapy but they usually come back

259
Q

what is blepharitis and the clinical signs

A

eyelids that are hyperemic, have edema, and are chronically distorted
causes blepharospasm, exudate, alopecia, ulceration, and hyperpigmentation
(think granulomatous, crusty, hairless, nasty eyelids)

260
Q

What are common causes of bacterial blepharitis (infected eyelids) in puppies and adults

A

puppies- juvenile pyoderma
adults- staphylococcus or streptococcus

261
Q

what are parasites that cause blepharitis in dogs and cats

A

demodex and sarcoptes

262
Q

what is a cause of immune mediated blepharitis that isn’t from an allergic reaction/insect bite

A

pemphigus foliaceus or erythematosus

263
Q

what is a chalazion

A

retained meibomian secretions that leak into surrounding tissue and cause an inflammatory response and granuloma formation

264
Q

What is a hordeolum

A

a stye, usually a staphylococcal infection of the lids that causes inflammation of glands of Zeiss and Moll or internal infection of meibomian gland

265
Q

what are the glands of Zeiss and Moll

A

Zeiss are the sebaceous glands of the eyelid margins and Moll are the apocrine (sweat glands) near the eyelid margin

266
Q

what are the conjunctival responses to disease

A

chemosis (edema), hyperemia, cellular exudate

267
Q

what is conjunctivitis

A

inflammation of the conjunctiva without concurrent uveitis or intraocular disease

268
Q

What is a major difference between canine and feline conjunctivitis

A

most of cat conjunctivitis is infectious and that is very rare in dogs

269
Q

A dog has bilateral follicular enlargement of the bulbar surface of the third eyelid, what could be causing this

A

seasonal allergies but you need to rule out KCS

270
Q

How should you treat allergic conjunctivitis

A

an anti-inflammatory and an antibiotic

271
Q

what are the most common differentials for feline infectious conjunctivitis

A

feline herpes-1, chlamydia psittaci, mycoplasma

272
Q

what is symblepharon and what is it usually happen in

A

Loss of conjunctival epithelium that causes inappropriate adherence of the conjunctiva to the eye, in young cats with herpes infections

273
Q

what is the treatment for feline herpes virus

A

No treatment but you van help control outbreaks + topical antibiotics for a secondary infection because of ulcers
topical trifluridine (if corneal disease) or cidofivir or idoxuridine
oral antivirals like famciclovir

274
Q

How is feline chlamydial conjunctivitis different than feline herpes

A

usually doesn’t have a URI where as that is how herpes usually starts

275
Q

how do you diagnose and treat feline chlamydial conjunctivitis

A

conjunctival cytology or IFA and treat with tetracycline, erythromycin, ciprofloxacin, and/or oral doxycycline

276
Q

What disease can cause unilateral or bilateral conjunctivitis in cats and it id diagnosed by inclusion bodies at the cell membrane

A

mycoplasma

277
Q

What is difficult about cytology or culture for feline conjunctivitis

A

Usually there is a low diagnostic yield

278
Q

What disease causes ropy, mucopurulent discharge with conjunctival hyperemia, chemosis, and keratitis with superficial neovascularization and pigmentation

A

Keratoconjunctivitis sicca (KCS)

279
Q

What part of the tear film is made by the meibomian glands, is superficial, and can stabilize and prevent evaporation

A

The lipid layer

280
Q

What part of the tear film is made by the lacrimal gland, gland of the third eyelid, and accessory glands, provides corneal nutrition and helps remove waste, and is the intermediate layer

A

Aqueous layer

281
Q

What part of the tear film is made by the conjunctival globlet cells and provides secretory IgA and is the interface of the tear film and the hydrophobic cornea

A

Mucus layer

282
Q

Where are the meibomian glands

A

In the tarsal plate

283
Q

A yorkie presents with a corneal ulcer that you suspect has a secondary infection. You have tried to treat this in the past and it keeps coming back. The dog also has dry and crusty nares. What may he have?

A

Keratoconjunctivitis sicca (KCS)

284
Q

Same yorkie with the ulcerated eye and dry, crusty nose. What test could you do to test for KCS and what value would be indicative

A

The Schirmer Tear test. Normal is 15-25mm/60sec, marginal is 10-15, and low is <10mm/60sec but you shoudl always evaluate the test and clinical signs together

285
Q

What is the most common form of keratoconjunctivitis sicca

A

Idiopathic/ immune mediated

286
Q

A dog presents to you and their owner said that the dog has recently undergone a surgery to remove its cherry eyes, but now it’s eyes are hyperemic with ropy discharge. What may have happened?

A

The third eyelid gland was probably excised when the cherry eye was removed causing keratoconjunctivitis sicca. This is why you should never remove a cherry eye and instead surgically correct it by tacking in down

287
Q

What causes unilateral neurogenic dry eye

A

Loss of parasympathetic activation of the lacrimal gland

288
Q

What is the difference between quantitative and qualitative dry eye

A

Quantitative is not enough production of the aqueous component of the tear film
Qualitative is a problem in the tear film breakup time (happens too fast), usually there is an issue with the mucin or lipid composition

289
Q

How can you test for qualitative dry eye and what test won’t work for it

A

You can use meibometry to examine the lipid component. Schirmer teat test wouldn’t work because it is for measuring the quantity of the aqueous portion of the tear film

290
Q

What are two causes of qualitative KCS

A

Loss of goblet cells (ex. from chronic inflammation) or dysfunction of the meibomian glands

291
Q

How can you stimulate tear production in keratoconjunctivitis sicca

A

Use cyclosporine A or tacroliums for life
Or pilocarpine (but this is reserved for cases of neurogenic KCS)

292
Q

When testing quantitative KCS there is a specific cut off that is used as a prognostic indicator for an individuals response to treatment. What is it?

A

If the Schirmer Tear Test is < 1mm/min usually only 50% will respond but if there is > or equal to 2mm/min then 80% are likely to respond

293
Q

What is a specific goal of KCS treatment which has a challenge with it specific to the type of medication used

A

You want to decrease inflammation so you can do this with cyclosporine or topical steroids, but many cases have ulcers and you can’t use steroids on an eye with an ulcer!

294
Q

Which drugs can be used with a mucin deficiency KCS as an “artificial tear” and how do they work (very basically)

A

Cyclosporine- stimulates the production of mucus
Polyvinlypyrrolidone- mimics mucus
Methylcelluloses- mimic mucus

295
Q

Which drugs can be used with a lipid deficiency KCS as an “artificial tear”

A

Refresh Endurance, soothe- oil based
Sodium hyaluronate
Warm compresses

296
Q

Describe a surgical treatment for KCS and what is the disadvantages

A

Transposition of the parotid salivary duct to the open conjunctiva but saliva are not tears so you have to clean their eyes more and there is a mineral deposition on the corneal and lid margins. Also sometimes the saliva is not comparable with the cornea

297
Q

What is the most common primary conjunctival disorder in dogs

A

Prolapse of the third eyelid gland (cherry eye)

298
Q

What causes a cherry eye (prolapse of third eyelid gland)

A

Weakness between the tissue attachments of the third eyelid and peri orbital tissues

299
Q

How many dogs will develop KCS if their cherry eye is surgically removed

A

50%

300
Q

Where can the third eyelid gland be anchored if a cherry eye is surgically fixed
What is another option for fixing a cherry eye

A

To the orbital rim
Or can use the pocket technique- two incisions make and you close the far edges of them to close it around the gland

301
Q

What causes a plasmoma (chronic superficial keratitis) and what is the treatment

A

Plasma infiltrate of the third eyelid (a variation of pannus) and you can use topical steroids or cyclosporine

302
Q

What is follicular conjunctivitis associated with

A

Large numbers of follicles on the bulbar surface of the conjunctiva, often associated with environmental allergens

303
Q

Where is a good place for a foreign body to hide that may cause a non-healing erosion

A

Behind the third eyelid

304
Q

What causes epiphora (excessive tearing of the eye), in regards to the nasolacrimal system

A

Poor drainage due to a hypoplasia or imperforate puncta or entropion
Blockage from a foreign body, inflammation or neoplasia

305
Q

Is puncta aplasia (imperforate punctum) common? What breeds/species are usually affected

A

Yes and you see it in cocker spaniels, goldens, miniature poodles, horses, llamas, and alpacas

306
Q

What is it called when you have mucopurulent discharge, epiphora (excessive watering of the eye), and may have swelling or draining fistulas in the medial can’t heal region

A

Dacryocystitis (inflammation of the tear ducts)

307
Q

What are the functions of the cornea

A

Transmission of light (transparent and refractive medium)
Defense- a barrier between the eye and the environment

308
Q

What are the layers of the cornea

A

Precorneal tear film, surface epithelium, stroma, Descemet’s membrane (the basement membrane), endothelium

309
Q

What are two functions of the corneal epithelium

A

Refraction- tear film “smoothens” the refractive surface
Mechanical barrier to fluid imbibition from the stroma

310
Q

T/F corneal edema will occur if the epithelium is damaged

A

True, it helps “hold in” the aqueous humor and when there is a loss of epithelium (like an ulcer) edema can occur because of fluid imbibition from the stroma

311
Q

Why are corneal ulcers so painful

A

The stroma is richly innervated

312
Q

Name four features of the normal corneal stroma

A

Avascular, non-pigmented and transparent, relatively dehydrated, regular collagen fibril arrangement

313
Q

What could cause the collagen fibrils in the cornea to spread out

A

Edema

314
Q

What is the meaning of corneal deturgescence and what helps the cornea achieve this

A

The corneal stroma is bathed in tears and aqueous humor but is still relatively dehydrated. It achieves this because tears are hypertonic and draw fluid out as they evaporate. Also, the epithelium is hydrophobic and so is the endothelium, but the endothelium has and NA-K ATPase pump to pump fluid into the anterior chamber. Lastly it is avascular

315
Q

What is the corneal endothelium made of and can you make more of it

A

It is a mono layer of squamous epithelial cells but they are post-mitotic so you can’t make any more of them

316
Q

What are the steps for stroma wound healing

A
  1. Invasion by neutrophils
  2. Wound margin keratocyte transformation to fibroblasts
  3. Fibroblasts invade wound
  4. Collagen and GAG synthesis
  5. Collagen reorganization
  6. Return of tensile strength
317
Q

Do you want angiogenesis in stromal healing

A

Definitely! It is basically necessary/enhances healing

318
Q

Which purkinje image is the cornea

A

The first one

319
Q

What are the three types of corneal vascularization/ causes of red in the cornea and what does each one indicate

A

Superficial- usually indicate ocular surface disease
Deep- into the stroma along the brush border and indicates intraocular disease (uveitis, glaucoma etc.)
Hemorrhage- indicates vascularization

320
Q

If you have a crystalline or chalky deposit in a cornea what could this be made of?

A

This could be a corneal deposit made of lipids (cholesterol) or mineral (calcium)

321
Q

How does a corneal scar differ from a deposit

A

It is usually more of a wispy grey to dense white and doesn’t have well defined edges or is chunky

322
Q

What does corneal cellular infiltrate look like and what can cause it
What is indicated when you have one

A

It is a yellow-white, creamy/soft to dense white
It can be inflammatory from infection or sterile (immune-mediated with WBCs) or neoplasia also may be associated with stromal loss or thickening
Cytology is indicated

323
Q

What does corneal edema look like

A

Hazy grey to a dense blue and maybe a cobblestone appearance
Will thicken the cornea which you can appreciate with a purkinje image

324
Q

What does cornea edema indicate

A

Epithelial defect (ulcer), endothelial defect/dysfunction (-itis, glaucoma, dystrophy or degeneration), or corneal vascularization

325
Q

What are keratin precipitates, where are they, and what do they indicate

A

They are tan-ish infiltrates (often sterile inflammatory cells) on the corneal endothelial surface that indicates anterior uveitis (intraocular inflammation)

326
Q

What can give you corneal pigment

A

Melanocytes from conjunctiva from chronic irritation or neoplasia
Or melanocytes from the uveal tract (iris) because of corneal perforation, congenital (PPM), Iridocilliary cyst, and of course neoplasia

327
Q

A cat has a history of ulcers and now there is a tan-ish black mark on its cornea, what could this be

A

A corneal sequestrum (only in cats), this is necrotic corneal stroma

328
Q

What is always indicated with a corneal ulcer

A

Steroids! Just kidding please don’t do this
It’s actually antibiotics because there is always a risk of secondary infection

329
Q

What are the etiologies for a cornea ulcer

A

Trauma- either direct or secondary (foreign body, entropion, tumor, etc.)
Exposure- lagophthalmos, buphthalmos, exophthalmos
Infection- FHV-1 (and other herpes viruses)
Tear film deficiency- ex. KCS
Neurological defects- CN V (neurotropic) and VII (paralytic)

330
Q

How long should it take an uncomplicated ulcer to heal

A

A week

331
Q

Corneal ulcers cause reflex _____

A

Anterior uveitis

332
Q

What are the specific clinical signs associated with anterior uveitis

A

Mitosis, aqueous humor flare in anterior chamber

333
Q

T/F just because an animal has an ulcer with severe uveitis doesn’t mean the ulcer is severe

A

False, the severity of the uveitis usually correlates with the ulcer

334
Q

Define a superficial, uncomplicated corneal ulcer

A

Acute and painful but has a distinct border and a tight edge. There is little corneal edema if any and no stroma loss. There also isn’t any infiltrate (uncomplicated) and no to mild reflex uveitis

335
Q

What can you give to help with the pain of a corneal ulcer

A

Atropine or NSAIDs

336
Q

What is SCCED and what is the common breeds and classic characteristics seen with them

A

Spontaneous chronic corneal epithelial defect, it is an indolent ulcer with non-adherent/loose epithelial edges (because the anterior stroma impairs normal epithelial adherence). Unlike other indolent ulcers there isn’t an underlying cause so it is usually a diagnosis by elimination Boxers, Corgis over represented
Will see a characteristic staining pattern where the stain seeps under the epithelial edge of the ulcer

337
Q

What is required for treatment of SCCED

A

Debridement with a Cotten tipped applicator or a diamond burr and anterior stromal puncture/ grid keratotomy (basically dragging a needle on the exposed stroma to promote healing)

338
Q

What is a descemetocele and how can you tell if you have one on an eye

A

Stromal loss down to Descemet’s membrane, will have a characteristic staining pattern where the Fluor. will stain a ring

339
Q

What are the etiologies for corneal malacia (melting)

A

Endogenous proteases/collagenases
Infection (bacterial collagenases)
Topical corticosteroids (and maybe NSAIDS)

340
Q

How should you assess a stromal ulcer

A

Look at the depth, the integrity (perforation risk, malacia), look for infiltrate, reflex uveitis and how bad it is/ if there at all, and any vascularization

341
Q

What type of antibiotic should you use for a corneal ulcer (assuming you don’t have a culture yet)

A

A broad spectrum and maybe a combo with an anti-fungal
Ex. Fortified cefazolin (gram + cocci) and fluoroquinolones or tobramycin (gram - rods)
No ointments with current or impending perforation!

342
Q

What can you use when you have a stromal ulcer with malacia to help treat the malacia

A

Serum, EDTA, or acetylcysteine

343
Q

What do you give to help with reflex uveitis with a stromal ulcer

A

Topical cycloplegia/ mydriasis- cholinergic/ parasympatholytic (atropine- but not if KCS or glaucoma)
Maybe systemic anti-inflammatory but also may delay corneal healing (and definitely no topical steroids!!)

344
Q

What animal is more likely to have reflex uveitis because of a stromal ulcer and what can be really bad with that animal specifically

A

A horse, the pain can also make them colic!

345
Q

T/F you should always preform a cytology in a horse with an ulcer

A

True

346
Q

T/f cats are the most likely to get ulcers from fungal infections

A

False! Way more common in horses

347
Q

What are some indications you may need to preform a conjunctival flap/graft or corneal transplant for a stromal ulcer

A

If there is rapid progression or malacia, limited or no vascularization, perforation or active leakage

348
Q

What disease is common in German shepherds, greyhounds, and some other dogs that is inherited and UV exacerbated, bilateral, chronic superficial keratitis

A

Pannus

349
Q

What is the treatment for pannus

A

Long term topical steroids and avoiding UV exposure

350
Q

What would cause white plaques of infiltrate in the cornea what is in cats and considered an immune-mediated keratitis. Hint- You do a cytology and see a bunch of a specific white blood cell

A

Eosinophilic keratitis

351
Q

What are inherited corneal lipid deposits known as (often in huskies)? Is there a treatment?

A

Corneal dystrophy, no treatment, usually bilateral and non-painful and minimally progressive

352
Q

What is an inherited/ age related change in the cornea that can cause edema and indolent ulcers

A

Endothelial degeneration

353
Q

What is it called when there is haired skin (or any abnormal tissue growing in an abnormal location) growing on the cornea

A

A dermoid or choristoma

Ophthalmology (2 decks)

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