Ophthalmology 1 Flashcards
1
Q
Voluntary eye movements
A
smooth pursuit
vergence
2
Q
involuntary eye movements
A
saccades
3
Q
Saccades
A
A quick, simultaneous movement of both eyes btw two or more phases of fixation in the same direction
4
Q
Six extraocular muscles facilitate eye movement
A
- Lateral rectus
- Medial rectus
- Inferior rectus
- Superior rectus
- Inferior oblique
- Superior oblique
5
Q
Oculomotor nerve (CN III) controls which muscle(s)?
A
Superior rectus
Inferior rectus
Medial rectus
Inferior oblique
6
Q
Trochlear nerve (CN IV) controls which muscle(s)?
A
Superior oblique muscle
7
Q
Abducens nerve (CN VI) controls which muscle(s)?
A
Lateral rectus muscle
8
Q
What are physiological reasons for us to have two eyes according to Manfred Fahle (neuro researcher)?
A
- Gives a spare eye in case one is damaged
- Gives a wider field of view (eg 190 degrees w/ two eyes; 40 degrees by one eye)
- Give precise depth perception
- It allows us to see more of or all of an object behind an obstacle
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
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
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
12
Q
Amblyopia: three main causes
A
- strabismus
- refractive error
- deprivation of vision 2/2 vision obstruction (cataract)
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)
14
Q
What do you need to consider in case of a Pt whose complains of double vision?
A
Cataract
15
Q
Strabismus: definition
A
A general term for gaze misalignment (a disconjugate gaze)
16
Q
Strabismus: cause
A
Strabismus can occur due to muscle dysfunction, farsightedness, central problems (cranial nerve palsies), trauma, or infections.
17
Q
Strabismus: risk factors
A
premature birth, cerebral palsy, and a family history of the condition
18
Q
Strabismus: types
A
- Esotropia: the eyes are misaligned towards the medially
- Exotropia: the eyes are misaligned laterally
- Hypertropia: the eyes are superiorly misaligned
- Hypotropia: the eyes are inferiorly misaligned
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).
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).
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
Eye exam (visual field): Key points
- Confrontation
- Visual field defects suggest a retinal (just one eye) or central process (both eyes)
* Central process --> refer to neurologist
26
Eye exam (proptosis): key points
- 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
Eye exam (anterior segment exam): Key points
Using either a slit lamp or magnifying glass, the anterior chamber and cornea
28
Eye exam (ophthalmoscopy): Key points
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
Eye redness: clinical term, causes
- 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
Subconjunctival hemorrhage: key points
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
Eye pain: key points
- 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
Foreign body sensation in the eye: key points
- 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
Photophobia: key points
- Corneal inflammation (keratitis)
- Anterior uveitis (iritis)
- Fever and other systemic conditions
34
Eye itching: key points
Almost always from an allergic condition
35
Eye watering: key points
- 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
Eye strain: key points
Assess visual acuity for signs of refractive errors
37
Conjunctival discharge: key points
- Purulent discharge usually indicates bacterial infection
- Watery discharge are usually viral conjunctivitis or keratitis
- Ropy, clear discharge with itching is usually allergic
38
Visual loss: key points
- 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
Diplopia (double vision): key points
- 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
Flashes and floaters: key points
- 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
Hordeolum (stye): Definition, S/Sx, cause, Tx
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
Chalazion: Definition, S/Sx, Tx
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
Blepharitis: Definition, cause, S/Sx, Tx
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
Entropion: Definition, cause, Tx
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
Ectropion: Definition, Tx
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
Dacrocystis: Definition, cause, characteristics,
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
Dacrocystis: S/Sx, Tx
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
Bacterial conjunctivitis: Characteristics, Spp., S/Sx
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
Viral conjunctivitis: S/Sx, cause
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
Herpetic conjunctivitis: S/Sx, Tx
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
Keratoconjunctivitis sicca (dry eyes): Causes, prevention
- 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
Keratoconjunctivitis sicca (dry eyes): S/Sx, Tx
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.
