Practical opthalmology lecture Flashcards
Patients may present WITHOUT an ocular complaint but…
STILL need their eyes examined! -new patient visits -wellness exam -pre-op exam -health certificate exam -non-ocular sick exam OR -with a primary ocular complaint
Ocular discharge normal but excessive..
Epiphora
Noted brown staining near the corners of the eye
How do you describe ocular discharge?
Abnormal color, consistency, translucency… unilateral or bilateral.
ID red eye
Slide 6
Could be allergic, infectious, or secondary to an underlying disease process (glaucoma)
ID conjunctivitis
Chemosis
Edema
Blepharospasm..
?
Photophobia..
?
ID change in corneal pigmentation..
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Change in pigmentation of the Iris..
Iris nevus (singular)
Iris nevi (plural)
Iris melanoma?
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Change in pigmentation of the sclera…
icterus
Prominent nictitans..
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Third eye lid mass…
Cherry eye!
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Entropion
Eyelids roll IN
*slide 14
Ectopion
Eyelids roll OUT
*slide 15
Abnormal eyelids
Agenesis (lid is absent)
*slide 16
Change in the shape of the globe.
Buphthalmos
*slide 17
Change in the size/shape of the pupils…
Anisocoria
*slide 18
Proptosis
*slide 19
Acute blindness
Slide 20
When patients present for a primary ocular complaint.. what do we need to know?
Clients perspective.. what have they noticed? what is there concern? Which eye? Both? How long? Has the condition progressed? Does the patient seem bothered? Blepharospasm? pawing at the eye? Third eyelid prominent? Rubbing? Change in behavior or activity? Known incident? Underlying medical conditions?
Hyperthyroidism (renal disease) can cause…
Hypertension > retinal detachment
Nutritional issues affecting the eye?
Taurine deficiency (cats and vegetarian diets)
Facial symmetry and/or distortion?
Ears, eyes, lips, nose..
Globe position..
Enphtalmos (eye sunken in)
Exophtalmos..
Globe is pushed out.
Decreased retropulsion as from space occupying mass or carnassial tooth root abscess.
Ptosis
Droopy lid
ID..
strabismus
Look for evidence of corneal trauma..
loss of translucency
loss of transparency
Trichiasis
Hair in normal site but misdirected towards the cornea..
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Distichiasis
extra eyelashes along the eyelid margin where they should not grow
*slide 37
Ectopic cilia
Eyelash emerges from the underside of the lid
*slide 38
Ocular exam..
Retropulsation
retropulse both of the globes (press with thumbs)
Menace response
Cranial nerves II and VII
*Wave hand in front of the eye, cover the other.
Palpebral reflex
CN V and VII
Pupillary light reflex
CN II and III Direct 100% pupillary constriction Consensual 50% pupillary constriction Pupillary constriction (parasympathetic pathway)
Advantages of direct opthalmosopy..
Greater magnification (greater detail)
Options (grid, slit, altering the dioptic power)
The fundus image is real, upright and 14x magnified in emmetropia (in the canine)
Disadvantages of ophthalmoscopy..
Small field of view
Short working distance
Lack of steroposis- monocular exam
Difficult to see through cloudy media (limited light source)
Difficult examining the peripheral fundus
Greater distortion when the visual axis is not completely transparent
Your face is very close to the patients muzzle!
ID the parts of the ophthalmic scope..
slide 45
Direct ophthalmoscopy..
To examine the right eye..
Stand or sit at the patients right side…
Hold the opthalmoscope with your right hand vertically infront of your right eye
Keep your index finger on the edge of the lens dial.
0 to -1 diopters focus on the fundus for most examiners
Keep both eyes open and look as though you are looking past the patient to block your own accomidation
Slide 49
Opthalmalogy lecture
Indirect ophthalmoscopy
Image is virtual and inverted.
The magnification depends on the focal length of the lens.
20 D lens: 4-5x mag less field of view
30 D lens: 2-3x mag but greater field of view
An important point to consider is that the axial magnification of the image varies with the species examined. For this reason a very mild elevation of the optic disc seen in a horse should be given much more significance than a disc of similar appearance in a dog as a horse optic nerve would be minifed a the lens strength.
Consider 14 D lens for horse exam.
Indirect ophthalmoscopy
Advantages
Larger field of view for fundic image Larger and safer working distance Stereopsis Ability to use both hands for patient examination Ability to see through cloudy media.
Indirect ophthalmoscopy
Disadvantages
Larger learning curve
Less magnification of structures, less detail
ID indirect opthalmascope..
slide 52
ID optic nerve
slide 53
Schirmer tear test
diagnose keratoconjuctivitis sicca (KCS, dry eye)
Fluorescein stain
Diagnose corneal ulceration
Tonometry
Diagnose glaucoma, high intraocular pressure
Uveitis = low intraocular pressure.