Reading assignment information-Chapter 7 The EYE Flashcards
What nerve is considered the “work horse” of the eye?
CN 3 (oculomotor)
What muscles are NOT innervated by CN3?
LR6SO4: Lateral rectus (CN 6) and Superior Oblique (CN4)
What are the 3 parts of the near reflex?
Accommodation
Convergence
Pupillary Constriction
What is the direct effect?
The constriction of the pupil of the eye on which the light is shined
What is the consensual effect?
The simultaneous constriction of the opposite pupil
Define accommodation
near focusing of the eye by increasing the power of the lens by contraction of the ciliary muscle innervated by CN3
What side of the eye is the optic disc located in?
the nasal side
What landmarks can you use to find the optic disc?
The anastomosis of the vessels will point towards the optic disk
What is the normal cup to disc ratio?
the cup should be 30% the size of the disc diameter
What are the major symptoms of eye disease?
Loss of vision Eye pain Diplopia Tearing and dryness Discharge Redness
What 2 questions must you ask when a pt c/o loss of vision?
Did the loss of vision occur suddenly?
Is the eye painful?
What questions must you ask if the pt states they have eye pain?
describe the pain? did it come on suddenly? Photophobia? Pain when you blink? FB sensation? H/A? Pain w/ movement? Pain over brow on same side? contact lenses?
What is the most common condition of dry eye?
inadequate amount of the water layer of tears-keratoconjunctivits sicca “dry eye syndrome”
What types of eye discharge exist? And what do they mean?
Watery/mucoid=viral or allergic
Purulent=bacterial infection
What does the physical exam of the eye include?
Visual acuity Visual fields Ocular movements External and internal eye structure Ophthalmoscopic exam
for VA: the first number on the chart is the distance at which ________ reads the chart; and the second number is the distance at which ________ reads the chart.
1st number : the distance at which the PATIENT reads the chart.
2nd number : the distance at which the person with normal vision can read the same line of the chart.
abbrev: OD
R eye
abbrev: OS
L eye
abbrev: OU
both eyes
How might you evaluate a patient who cannot read any line of print on the charts?
Finger counting ability
How might you evaluate a patient who cannot see well enough finger counting?
ability to see light
define scotoma?
An area of depressed vision
What is the physiological scotoma?
The “blind spot” located approx 15 to 20 degrees temporal to central fixation-it corresponds with the optic nerve head.
define hemianospia?
absence of half of the visual field
What is bitemporal hemianopsia? What is it a sign of?
a defect in both temporal fields. Results form lesion involving the optic nerve at the level of the optic chasm-often the result of pituitary tumor.
What is the most common type of visual field loss?
Homonymous hemianopsia-occurs frequently in stroke pts
What is assessed when testing ocular movement?
Eye alignment (light reflection) Cover test (for strabismus) 6 cardinal positions of gaze (EOM's) Pupillary light reflex Near reflex
In Marcus Gunn or RAPD phenomenon what is the most extreme example?
When the light is shone in the blind eye, there is neither a direct or consensual response. When the light is moved to the other eye, there is both direct and consensual response (this is bc both afferent and efferent pathways are normal. When the light is swung back to the blind eye, no impasse are received by the retina (afferent), and the pupil of the blind eye no longer remains constricted; it therefore dilates.
When the patient looks far to near what should occur?
The eyes should converge and the pupils should constrict.
What do we examine on External and internal eye structure inspection?
Orbits and eyelashes Lacrimal apparatus Conjunctiva Sclera Cornea Pupils Iris Anterior chamber Lens
What sings should be watched for when inspecting the eyelid?
drooping infection erythema swelling crusting masses other abnormalities
Define ptosis (aka blepharoptosis)
drooping of the eyelid
Define Kearns-Sayre syndrome
Chronic progressive external ophthalmoplegia-slow progressive symmetric ptosis and symmetric external ophthalmoplegia caused by an autosomal-dominant condition
Define Lagophthalmos
Inability to close the eyelids completely.-seen in thyroid dz
entropion
a turning in of the eyelid
ectropion
a turning out of the eyelid
What is the most common type of malignancy associated with cutaneous horn?
Squamous cell carcinoma is most common type of malignancy at the base of the horn
Define Sturge-Weber syndrome
Congenital condition recognizable by a characteristic port wine stand on one side of the face.
Chalazion
meibomian gland obstruction. Tx with warm compresses
What is indicated by orbital discoloration of “raccoon eyes”?
basilar skull fracture
Xanthelasma
yellowish plaques on the periorbital skin
Stye (acute external hordeolum)
localized abscess caused by a staph infection.