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AGACNP > Ophthalmology 1 > Flashcards

Ophthalmology 1 Flashcards

1
Q

Voluntary eye movements

A

smooth pursuit

vergence

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2
Q

involuntary eye movements

A

saccades

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3
Q

Saccades

A

A quick, simultaneous movement of both eyes btw two or more phases of fixation in the same direction

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4
Q

Six extraocular muscles facilitate eye movement

A
  1. Lateral rectus
  2. Medial rectus
  3. Inferior rectus
  4. Superior rectus
  5. Inferior oblique
  6. Superior oblique
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5
Q

Oculomotor nerve (CN III) controls which muscle(s)?

A

Superior rectus
Inferior rectus
Medial rectus
Inferior oblique

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6
Q

Trochlear nerve (CN IV) controls which muscle(s)?

A

Superior oblique muscle

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7
Q

Abducens nerve (CN VI) controls which muscle(s)?

A

Lateral rectus muscle

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8
Q

What are physiological reasons for us to have two eyes according to Manfred Fahle (neuro researcher)?

A
  1. Gives a spare eye in case one is damaged
  2. Gives a wider field of view (eg 190 degrees w/ two eyes; 40 degrees by one eye)
  3. Give precise depth perception
  5. It allows us to see more of or all of an object behind an obstacle
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9
Q

Amblyopia

A
  • Lazy eye
  • Results in decreased vision in an eye that otherwise typically appears normal
    The brain starts to favor the unaffected eye and eventually this eye gets “stronger” causing problems with:
    1. Pattern recognition
    2. Poor visual acuity,
    3. Low sensitivity to contrast and motion
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10
Q

Amblyopia: pathophysiology

A
  • Lazy eye
  • Results in decreased vision in an eye that otherwise typically appears normal
    The brain starts to favor the unaffected eye and eventually this eye gets “stronger” causing problems with:
    1. Pattern recognition
    2. Poor visual acuity,
    3. Low sensitivity to contrast and motion
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11
Q

Amblyopia: characteristics

A
  • Most common cause of decreased vision in a single eye among children and younger adults (**children may have reading problems –> usually a slow reader)
  • Due to brain “plasticity” in young children, this allows the brain to correct for diplopia (double vision), as the brain ignores input from the weaker eye
  • If something happens in later age, the brain cannot, and therefore would result in diplopia
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12
Q

Amblyopia: three main causes

A
  1. strabismus
  2. refractive error
  3. deprivation of vision 2/2 vision obstruction (cataract)
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13
Q

Amblyopia: Tx

A 
Strengthening the weaker eye by depriving the stronger one w/ eye patches/glasses w/ one lens occuluded
Pharmacologic penalization (mydriatics)
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14
Q

What do you need to consider in case of a Pt whose complains of double vision?

A

Cataract

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15
Q

Strabismus: definition

A

A general term for gaze misalignment (a disconjugate gaze)

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16
Q

Strabismus: cause

A

Strabismus can occur due to muscle dysfunction, farsightedness, central problems (cranial nerve palsies), trauma, or infections.

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17
Q

Strabismus: risk factors

A

premature birth, cerebral palsy, and a family history of the condition

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18
Q

Strabismus: types

A
  1. Esotropia: the eyes are misaligned towards the medially
  2. Exotropia: the eyes are misaligned laterally
  3. Hypertropia: the eyes are superiorly misaligned
  4. Hypotropia: the eyes are inferiorly misaligned
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19
Q

Myopia (nearsightedness): definition

A

This can arise from a cornea or crystalline lens with too much curvature (refractive myopia) or an eyeball that is too long (axial myopia).

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20
Q

Hyperopia (farsightedness): definition

A

This can arise from a cornea or crystalline lens with not enough curvature (refractive hyperopia) or an eyeball that is too short (axial hyperopia).

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21
Q

Presbyopia: definition

A

When the flexibility of the lens declines, typically due to age. The individual would experience difficulty in near vision, often relieved by reading glasses, bifocal, or progressive lenses.

22
Q

Astigmatism: definition

A

A person with astigmatic refractive error sees lines of a particular orientation less clearly than lines at right angles to them

23
Q

Eye exam (pupil): Key points

A
  • Pupils, for their light reflex and ability to accommodate and focus
  • A poorly reactive pupil suggests CNIII palsy, iris damage as in acute glaucoma, or Horner’s Syndrome
24
Q

Eye exam (extraocular movements): Key points

A
  • First, examine if the gaze is conjugate (aligned), when looking at the examiner and following the examiner’s finger
  • Next, examine for a gaze palsy, again suggesting CN palsy
  • Look for nystagmus (*rotate beats are ALWAYS pathological)
25
Q

Eye exam (visual field): Key points

A
  • Confrontation
  • Visual field defects suggest a retinal (just one eye) or central process (both eyes)
  • Central process –> refer to neurologist
26
Q

Eye exam (proptosis): key points

A
  • Proptosis, which involves forward displacement of the globe and widening of the palpebral aperture so as to expose sclerae superior and inferior to the iris
  • Observe from above the patient
  • The most common cause is dysthroid eye disease (chronic inflammatory cell infiltration of the orbital tissues and extra ocular muscles, most often from hyperthyroidism), other causes include extraxial brain tumors
  • Unilateral proptosis –> possible brain tumors
27
Q

Eye exam (anterior segment exam): Key points

A

Using either a slit lamp or magnifying glass, the anterior chamber and cornea

28
Q

Eye exam (ophthalmoscopy): Key points

A

Dilating the pupils allows for the best view of the retina, where the examiner should assess for optic disc swelling, hemorrhages or exudates, and for clarity of the vitreous

29
Q

Eye redness: clinical term, causes

A
  • The clinical term is conjunctival injection
  • Usually caused by hyperemia of the conjunctival, episcleral, or ciliary blood vessels
  • Sometimes caused by subconjunctival hemorrhage (which is nearly always alarming but completely benign)
30
Q

Subconjunctival hemorrhage: key points

A

Subconjunctival hemorrhage is often:

  1. Spontaneous in supratherapeutic INR
  2. Seen after violent vomiting
  3. Traumatic, if “poked” in the eye
  4. Not associated with anything more severe than a mild foreign body sensation in the eye
31
Q

Eye pain: key points

A
  • Eyes shouldn’t ever “hurt” but if they do, take a careful history about whether one eye hurts (more concerning) or if both eyes hurt (probably not something eye-related)
  • Sudden increase in intraocular pressure as seen in acute angle closure glaucoma
32
Q

Foreign body sensation in the eye: key points

A
  • The patient is often correct, even if you can’t see a foreign body right away, keep looking
  • Corneal abrasions and ulcers cause this
33
Q

Photophobia: key points

A
  • Corneal inflammation (keratitis)
  • Anterior uveitis (iritis)
  • Fever and other systemic conditions
34
Q

Eye itching: key points

A

Almost always from an allergic condition

35
Q

Eye watering: key points

A
  • Inadequate drainage from infection (dacrocystis) or inflammation of the lacrimal drainage system
  • Often occurs as a reflex in corneal disorders (the body will try to wash out a foreign body)
36
Q

Eye strain: key points

A

Assess visual acuity for signs of refractive errors

37
Q

Conjunctival discharge: key points

A
  • Purulent discharge usually indicates bacterial infection
  • Watery discharge are usually viral conjunctivitis or keratitis
  • Ropy, clear discharge with itching is usually allergic
38
Q

Visual loss: key points

A
  • Blurry vision is often a refractive error, corneal opacity (cataract), intraocular inflammation (uveitis), retinal detachment involving the macula, optic nerve disorders
  • Monocular field loss usually indicates disease of the retina or the optic nerve
  • Binocular field loss usually indicates a central nervous system lesion, as in a stroke
39
Q

Diplopia (double vision): key points

A
  • Usually from acquired ocular misalignment (will resolve after one eye is covered)
  • Central disorders of eye movement
  • Cranial nerve palsies as the result of trauma (muscle entrapment due to orbital fracture), neoplastic or inflammatory disease, Wernicke’s syndrome, Myasthenia Gravis
  • Monocular diplopia (will not resolve when the fellow eye is covered), suggests a refractive error
40
Q

Flashes and floaters: key points

A
  • Usually indicates a retinal problem and suggests the need for dilated fundal examination to exclude a retinal tear or detachment
  • Occasionally due to migraine phenomena
41
Q

Hordeolum (stye): Definition, S/Sx, cause, Tx

A

Definition: Staphylococcal abscess in the eye lid
S/Sx: red, swollen, acutely tender area of the lid
Cause: Occasionally occur on the inside of the lid and is caused by a blocked Meibomian gland
Tx: Warm, wet compresses are the most effective, and it usually resolves in 2-3 days
During the acute phase, application of erythromycin or bacitracin ointment can help as well
*If it does not resolve, incision and drainage is needed

42
Q

Chalazion: Definition, S/Sx, Tx

A

Definition: characteristically firm and painless lid nodule
S/Sx: Usually, it is firm, nonerythematous, nonfluctuant, and nontender
Tx: the gland will need to be surgically excised

43
Q

Blepharitis: Definition, cause, S/Sx, Tx

A

Definition: Blepharitis is a common chronic bilateral inflammatory condition of the lid margins
Cause: Can be caused by staphylococci or seborrheic dermatitis; Can be caused by use of old or dirty eye makeup, or false eyelashes
Symptoms: iirritation, burning, and itching
Tx: Better hygiene often resolves the problem without medicine, but occasionally persistent cases can be treated with antibiotics:
- Systemic antibiotics: minocycline, tetracycline, doxycycline
- Topical antibiotics: ciprofloxacin 0.3% eye drops

44
Q

Entropion: Definition, cause, Tx

A

Definition: inward turning of the lid
Cause: usually caused by chronic scarring of the palpebral conjunctiva resulting from long-lasting irritation and inflammation
Tx: Surgical treatment is needed if the lashes rub against the cornea, but can sometimes be avoided by botulinum toxin injection

45
Q

Ectropion: Definition, Tx

A

Definition: Ectropion is the outward turning of the lower lid, and is common with advanced age (*Imagine droopy dog
Tx: Surgical treatment is indicated if there is excessive tearing, exposure keratitis, or for cosmesis

46
Q

Dacrocystis: Definition, cause, characteristics,

A

Definition: Infection of the lacrimal sac due to an obstruction of the nasolacrimal drainage system. Staphylococci and Candida are the most common infectious causes
Characteristics: Can be acute or chronic and is more common in the very young and very old

47
Q

Dacrocystis: S/Sx, Tx

A

S/Sx: Usually unilateral. Usually pain, swelling, redness and tenderness to the lacrimal sac, and on palpation, purulence can be expressed from the lacrimal sac
Tx:
- Usually responds well to systemic, not topical, Abx Tx
- Rarely, surgery is needed

48
Q

Bacterial conjunctivitis: Characteristics, Spp., S/Sx

A

Characteristics: very common & contagious
Common spp: S. pneumoniae, Haemophilus spp, Pseudomonas spp, and Moraxella spp.
Occasionally N. gonorrhea & C. trachomatis
S/Sx:
- Typically monocular
- Conjunctival injection and an irritated feel and appearance to the eye, purulent discharge (worst in the morning)
-No visual impairment, acuity is preserved

49
Q

Viral conjunctivitis: S/Sx, cause

A

S/Sx: Involves both eyes
There is also usually other constitutional symptoms like pharyngitis, fever, fatigue and preauricular adenopathy (referred to as “pharyngoconjunctival fever”)
The discharge is usually watery, not purulent
Cause: Adenoviruses,
Tx: require no treatment, but antihistamines can offer some symptom relief

50
Q

Herpetic conjunctivitis: S/Sx, Tx

A

S/Sx: zoster rash near the eye, and “dendritic lesions” can be seen on fluorescein exam
Tx: Must be treated with acyclovir
*irreparable damage to the cornea may result without treatment

51
Q

Keratoconjunctivitis sicca (dry eyes): Causes, prevention

A
  • Result of environmental factors, or from diseases affecting tear production (Sjögren’s Syndrome)
  • Seen in competitive swimmers, as constant chlorine exposure will dry out the eye
    -Occasionally is iatrogenic, as when patients are sedated or under anesthesia, the blink reflex slows or is absent
    In intubated patients, artificial tears should be used often
  • Patients under anesthesia should have eyes taped shut
52
Q

Keratoconjunctivitis sicca (dry eyes): S/Sx, Tx

A

S/Sx: Pt will complain of “bloodshot eyes” (always both), that feel dry, might sting, but visual acuity is preserved; eye may well appear “dried out” as well on the exam
Tx: depends on the cause.

AGACNP (21 decks)

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