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Flashcards in CM- Physical Exam of the Eye Deck (46)
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1
Q

What are the 8 parts of a general eye exam?

A
  1. visual acuity
  2. external examination
  3. pupillary reactions
  4. ocular motility and alignment
  5. visual fields
  6. anterior segment examination
  7. intraocular pressure
  8. funduscopic examination
2
Q

What 4 symptoms raise index of suspicion for a more serious sight threatening disorder?

A
  1. decrease of vision
  2. photophobia
  3. diplopia
  4. deep aching ocular pain
3
Q

What 6 signs raise the index of suspicion for a serious sight-threatening disorder?

A
  1. decreased vision
  2. corneal edema
  3. corneal ulcers/infiltrates
  4. circumcorneal redness
  5. abnormal pupil
  6. elevated intraocular pressure
4
Q

What 3 pieces of equipment are necessary to perform an adequate eye exam?

A
  1. visual acuity chart [or card]
  2. light source [penlight]
  3. direct opthalmoscope

*access to mydriatic drop, tonometer, pair of loupes or slit lamp would further enhance

5
Q

What must light focus on to achieve sharp, clear central vision?

A

fovea of the retina

6
Q

What 2 structures of the eye provide refractive power to help focus light onto the fovea?

A

2/3 of refractory power comes from the cornea

1/3 comes from the lens

7
Q

What is myopia, hyperopia, and astigmatism?

A

Myopia- the eye is too long, so visual acuity is lost at far distances

Hyperopia- the eye is too short, so visual acuity is lost at short distances

Astigmatism- of the refracting power is different in one meridian than another [ex. horizontal and vertical don’t agree] then vision will be blurry

8
Q

What is accommodation?
Describe the process of accommodation.

What is it called when accommodation is lost with age?

A

Accommodation is the ability of the lens to assume a more convex shape in response to ciliary muscle contraction.

When looking far way, the cililary muscles are relaxed, and the zonules are tighted flattening the lens.
When changing to look at something closer, the ciliary muscles contract, zonules relax, and the lens curves [convex]

Presbyopia is the loss of accommodation with age and usually manifests around 40

9
Q

Describe the proper technique for Standard Snellen visual acuity.

A
  1. Patient should be wearing corrective lenses and you should make them cover one eye to test each eye individually
  2. Distance visual acuity is preferred and the chart is at 20 feet from the patient.
  3. patient reads the smallest letters/numbers they can
    - results are recorded as 20 over whatever number [20/40 means that this person can read at 20ft what a normal person can read at 40]
    - patient gets credit if they can read 1/2 the line
  4. if the patient cannot see the largest letter on the chart, they are asked to count the examiners fingers at 5ft
  5. if the patient cannot see the fingers, they are asked to detect motion [wave of examiners hand] at 10ft
  6. if patient cannot detect hand movements, the examiner uses penlight to see if patient can detect light [LP or NLP =light perception or no]
10
Q

If you cannot do a standard snellen with distal visual acuity, how do you perform with a pocket visual screener?

A

The card provides “near-equivalent” Snellen acuity

  1. wear corrective lenses [and if over 40 bifocals]
  2. hold card 14 to 16 inches from face
  3. test each eye individually
11
Q

Why is is crucial to test each eye individually for Snellen visual acuity tests?

A

Testing both eyes together would mask unilateral vision loss

12
Q

What are 4 common lid abnormalities that should be able to be diagnosed on visual examination of the eye?

A
  1. entropion - the lid is turned inward and the lashes rub against the ocular surface
  2. ectropion - lid is turned outward, tears flow onto cheeks; conjunctiva is dry and keratinized
  3. Ptosis - drooping of one or both eyelids
    - isolated [congenital, acquired]
    - neurologic or systemic disorder [Horner’s, 3rd nerve palsy]
  4. retraction- seen with Graves
13
Q

Systemic diseases can be associated with signs on the ocular adnexa [orbit, conjunctiva, eyelids]. What are 2 examples?

A
  1. Xanthelasma- benign histiocytic tumor that has cholesterol laden macrophages. It presents as yellow plaques underneath the medial canthal area
  2. Proptosis- forward displacement of the eye, and lower lid edema are signs of Graves
14
Q

Describe the anatomy of the pupillary reflex.

[how does information of light travel]

A
  1. light strikes one eye, and the info is carried posteriorly through the optic nerve
  2. Half the fibers decussate at the optic chiasm into the contralateral optic tract, half stay in the ipsilateral optic tract
  3. 2/3 along the optic tract, some fibers leave and enter the superior colliculus and go to the pretectal nucleus.
  4. From the pretectal nucleus, information passes to Edinger-Westphal nucleus bilaterally
  5. From here pupillary motor commands travel with the 3rd CN through the superior orbital fissure to the ciliary ganglion and iris sphincter.
  6. Iris sphincter constricts to make the pupil smaller

LIGHT SHINED IN ONE EYE SHOULD TRANSMIT TO BOTH PUPILS EQUALLY

15
Q

How do the sphincter of the iris [constrictor] and dilator of the iris differ in terms of innervation?

A

Constrictor is a parasympathetic response from EW nucleus in the midbrain

Dilator is sympathetic

16
Q

Describe the pathway for eye dilation.

A
  1. first order neurons are in the hypothalamus
  2. course down the brainstem to cilio-spinal center of Budge [C8-T2]
  3. Second order neurons exit spinal cord, cross apex of the lung, and end at superior cervical ganglion
  4. third order neurons ascend with common and internal carotids to join the opthalmic artery in the carvernous sinus –> iris dilator muscle
17
Q

What 3 features are associated with the near synkinetic response?

A
  1. convergence - eyes rotate towards each other
  2. accommodation - lens becomes convex
  3. miosis- pupil shrinks
18
Q

How do the pathways for light induced pupillary constriction and near synkinetic pupillary constriction differ?

A

Light–> optic tract –> pretectal nucleus–> EW

Near–> peristriate cortex [more ventral in the midbrain then the light reflex pathway] –>EW

Both near and light have a common final pathway from EW nucleus via 3rd cranial nerve through ciliary ganglion to the iris sphincter muscle

19
Q

What is Argyll-Robertson pupils for syphilis?

A

Pupils get small with accomodation to near objects but do NOT get smaller with light.

20
Q

Describe “normal” pupils on physical exam.

A
  1. round
    - peaked or irregular is a sign of trauma/surgery
    - absence is called aniridia
  2. equal size
    - 20% have physiologic anisocoria [unequal size pupils] but the difference is less than 2mm and difference remains constant despite illumination changes
21
Q

How can you differentiate physiologic anisocoria from Horner’s syndrome?

A

Physiologic anisocoria is when a person has unequal size pupils [usually different by less than 2mm]. The pupils remain the same difference in size despite changes in illumination

Horner syndrome- anisocoria is greater in dim light than in bright light

22
Q

What can cause Horner syndrome?

What are the common clinical findings?

A

A lesion anywhere in the sympathetic pathway can cause Horner syndrome.

  1. miosis of the affected side
  2. slight ptosis of the upper lid [2-3mm]
  3. narrow palpebral fissure

If the lesion is proximal to the bifurcation of the carotid, anhydrosis of the ipsilateral face may occur.

It can be benign, but is frequently associated with apical lung tumors, thoracic aortic aneurysms, neuroblastomas, or trauma to brachial plexus

23
Q

What should you suspect if anosocoria is greater in bright light?
Dim light?

A

If the difference in pupil size is greater in bright light, you should suspect 3rd nerve palsy [oculomotor nerve palsy]

If the difference is greater in dim light, you should suspect Horner syndrome [sympathetic problem]

24
Q

A patient presents with a fixed, dilated pupil.
They have anosocoria that is worse in bright light.
You note ptosis and extraocular muscle dysfunction. What is the likely problem?

What is the most common non-traumatic cause of this presentation?

A

3rd cranial nerve palsy

Most common non-traumatic cause is posterior communicating artery aneurysm

25
Q

If a comatose patient presents with a unilateral blown pupil, what should you be suspicious of?

A

This is called Hutchinson pupil and it typically indicates herniation of the uncus putting pressure on the contralateral 3rd nerve

26
Q

Describe how the direct response to light is tested.

What do you do if the patient has a sluggish pupillary response?

A
  1. shine a light in the patients eye.
  2. measure how brisk the constriction of the pupil was [4+ is very brisk, 1+ is sluggish]
  3. if the patient has a sluggish response, test the near response by having the patient focus on a far away object and then fixate on a near object w/in 6 inches of the face [convergence and constriction should be observable]
27
Q

How should the light and near response compare?

A

The light response should be equal to or greater than the near response. If it is not, this is light-near dissociation

28
Q

How is consensual pupillary reflex tested?

A

Swinging flashlight test

  • normally both pupils should constrict when a light is shown in either eye
    1. tell patient to focus on a distant object in a moderately dark room
    2. shine light in the right eye [both pupils should constrict]
    3. swing the light to the left eye [both pupils should remain constricted]
29
Q

How can you detect an afferent pupillary defect [Marcus Gunn pupil] with the swinging flashlight test?

A

If when you swing the flashlight to the other eye, both pupils dilate, this is a sign of an afferent defect on the second eye. [optic nerve or extensive retinal damage]

When you swing the flashlight back to the first eye, they will constrict again

30
Q

How can you differentiate efferent and afferent pupillary defects?

A

Efferent- CN3 defect. If there is a problem with the left and you shine a light in the right, the right will constrict. If you move a light to the left, the left will not shrink, but the right will remain constricted [because afferent pathway to EW nucleus and right circuitry are still intact.

Afferent- optic nerve [CN2] defect. If there is a problem with the left eye, if you shine a light in the right eye, both pupils will get small. If you swing the flashlight to the left, both eyes will dilate.

31
Q

What muscles are controlled by CN 3, 4, and 6?

A
3= SR, IR, MR, IO, levator palpebrae
4= SO
6 = LR
32
Q

How is ocular motility tested?

A

Examine the eyes in the 6 cardinal positions of gaze.

  1. gazing right isolates left MR and right LR
  2. gazing up and in isolates inferior oblique
  3. gazing down and in isolates SO
  4. gazing up and out isolates SR
  5. gazing down and out isolates IR
  6. gazing left isolates left LR and right MR
33
Q

What is esotropia?

What are the 3 ways it can occur?

A

Crossing of the eyes

  1. acquired localized problem
  2. CN6 palsy
  3. increased intraocular pressure
34
Q

What is extropia?

What are the 2 causes?

A

It is an outward deviation of the eyes

  1. localized childhood problem
  2. CN3 palsy
35
Q

How are visual fields assessed clinically?

A

“3 stage confrontation”

  1. sit 3 feet from the patient, cover one eye and have the patient cover the same while keeping fixation on each others eyes
  2. put your hand in different quadrants midway btwn you and the patient and have them count the fingers
  3. present fingers on both hands simultaneously in 2 quadrants and have the patient count
  4. hold both palms forward to the patient and ask if they note any differences
  5. test the opposite eye in the same fashion
36
Q

What is the purpose of a visual field map?

Describe a visual field map.

A

Visual field map helps localize lesions in the visual pathways that may cause disturbances in vision.

Map:

  1. center is fixation where the patient is looking and has the greatest visual acuity
  2. draw the map as if you are looking out the patients eyes
  3. the physiological blind spot [where optic nerve exits the globe and there is no photoreceptors] is marked on the horizontal meridian lateral to fixation
37
Q

What is a scotoma?
What is central scotoma?
What is metamorphopsia?

A

Scotoma = blindspot
Central scotoma = damage to the macula
Metamorphopsia = distortion of shapes of objects [due to damage to the macula]

38
Q

How does the retinal image compare to the object in space?

A

Retinal images are reversed and inverted compared to objects in space

[inferior retinal lesion = superior field defect]

39
Q

What fibers cross and the optic chiasm and which remain ipsilateral?

A

At the optic chiasm, nasal retinal fibers [temporal visual fields] decussate.

Temporal fibers [middle visual fields] remain ipsilateral

40
Q

Posterior to the optic chiasm, the lateral geniculate, optic radiations and occipital cortex carry information from the ____________ visual field.

A

Contralateral

41
Q

What tool is used to test the anterior segment of the eye?
What anatomical structures are included in the “anterior segment’?
Describe the appearance.

A

To test the anterior segment, you need a penlight or slit lamp biomicroscope.

Ant. Segment :

  1. sclera
  2. conjunctiva
  3. cornea - illuminated in cross section
  4. iris
  5. anterior chamber -dark space between cornea and yellowed crystalline lens
42
Q

What is a pinguecula?

What is a pterygium?

A

Pinguecela is a yellow plaque at the interpalpebral fissue [medial or lateral]. It is localized elastotic degeneration of subconjunctival tissue due to UV radiation.

Pterygium is advanced pinguecela that is red/inflammed and advancing onto the cornea

43
Q

What is arcus senilis?

What is arcus juvenilis?

A

Senilis:
hazy grey peripheral cornea due to long-standing accumulation of lipids in the area.
Found in elderly

Juvenilis:
hazy grey peripheral cornea due to lipids in a person under 50. Suggests elevated serum cholesterol/lipids

44
Q

How does aqueous humor form? How does it drain?

A
  1. produced by ciliary bodies
  2. flows to ant chamber by going through space btwn lens and pupillary border w/iris
  3. exits the eye via trabecular meshwork at internal angle [iris/cornea] into the venous system
45
Q

How is intraocular pressure measured?
What is normal pressure?
Who should be measured for intraocular pressure?

A

tonometer

Normal pressure is below 22mmHg

46
Q

A patient presents with mid-dilated fixed pupil, cloudy cornea, eye pain, nausea and vomiting.
You have them close their eye and push on it with your fingers. It feels rock hard.

What is it likely that this patient has?

A

Acute angle closure glaucoma