Ophthalmology Flashcards
OD vs OS
OD (oculus dexter) right eye
OS (oculus sinister) left eye
OU (oculus uterque) both eyes
Explain how to interpret snellen chart results
In this notation, the first number
represents the distance between the patient and the eye
chart (usually the Snellen eye chart); the second number
represents the distance at which the letters can be read by
a person with normal acuity. Visual acuity of 20 / 80 thus
indicates that the patient can recognize at 20 feet a symbol
that can be recognized by a person with normal acuity at
80 feet.
How should visual acuity be measured if visual acuity is 20/40 or less in one or both eyes?
repeat the test with the subject viewing the test chart
through a pinhole occluder and record these results. The
pinhole occluder may be used over the subject’s glasses.
If a patient cannot see the largest Snellen letters, proceed to reduce the distance
How is visual acuity tested if they are unable to see snellen chart from 3 or 1.5 m?
- Reduce distance to chart
- Count fingers
- Hand movement
- Light perception
- No light perception (NLP)
Marcus Gunn pupil
afferent pupillary defect that can be detected with swinging torch test
affected eye has less response to light
What are normal vs abnormal response on swinging-torch pupil examination?
A normal response is initial
pupillary constriction followed by variable amounts of
redilation.
An abnormal response is slow dilation without
initial constriction. The relative afferent pupillary defect
almost always indicates a lesion in the optic nerve on the
affected side.
What is a normal optic cup size?
The size of the physiologic cup varies
among individuals. Normal cup:disc diameter ratio is .3 to .6
Larger C/D ratios may be a sign of glaucoma.
Steps in Eye Examination
· Measure the visual acuity for each eye.
· Test the pupils for direct and consensual responses.
· Test the extraocular movements.
· Inspect the lids and the surrounding tissues.
· Inspect in order : conjunctiva, sclera, cornea and iris.
· Assess the anterior chamber for depth and clarity.
· Assess the lens for clarity through direct
ophthalmoscopy
· Use the ophthalmoscope to study the fundus,
including the disc, vessels, and macula.
· Perform a confrontation field test for each eye.
· Perform tonometry when indicated.
Presentations where eye examination is essential
- Headache
- Signs of raised ICP
- Malignant hypertension
- Sudden visual loss
Important Nerves for eye examination
- II- Optic
- III- Oculomotor
- IV- Trochlear
- VI- Abducens
Assessing the OPTIC (CN II) function
AFRO • Acuity • Fields • Reaction • ophthalmoscopy
Causes of Relative Afferent Pupillary Defect
optic neuritis
advanced glaucoma
Where is the lesion in a lower homonymous quadrantanopia?
lesion at left parental radiation
Where is the lesion in a upper homonymous quadrantanopia?
lesion at left temporal radiation
Causes of Eye movement disorders
- Brainstem disorders
- Cranial nerve palsies
- Hypertension, diabetes
- Intracranial aneurysm or cavernous sinus lesion
- Myasthenia gravis
- Muscle disease
Symptoms of eye movement disorders
- Diplopia (III= complicated, IV= vertical, VI= horizontal)
- Others
- droopy eyelid, dilated pupil, neurological etc.
What is binocular vs monocular diplopia?
Binocular Diplopia: Goes when one eye closed. Caused by misalignment between two eyes
Monocular Diplopia: Often more than 2 images, Present when one eye open, Caused by disturbances in optical media.
Signs of third cranial nerve palsy
- Signs- “Down and out”
- Ptosis
- Pupil- may be dilated/ “blown out”
Why would patient have dilated pupil in third nerve palsy?
parasympathetic fibres run along CN3
Why would patient have ptosis in third nerve palsy?
CN III supplies levator palpebrae
Causes of 4th CN nerve palsy
Very hard to pick up - Superior oblique isn’t working
- Trauma - susceptible due to long passage through cranial vault
- Congenital
- Ischemic (diabetic)
- SOL
presentation of 6th CN nerve palsy
Eye can’t abduct past the midline
Causes of 6th CN nerve palsy
Associated with: • Cardiovascular • Raised ICP • Demyelination • Vasculitis
Note: Abducens nerve runs up the floor of the skull to get to the cavernous sinus and into the orbit. When enters cavernous sinus, it makes an abrupt 90-degree bend. It is susceptible to high intracranial pressure
How can you differentiations between myasthenia graves eye features and CN palsy?
Myasthenia gravis can mimic any nerve palsy
But NEVER effects pupil
Hutchinson’s sign
Vesicles on the tip of the nose, or vesicles on the side of the nose, precedes the development of ophthalmic herpes zoster.[This occurs because the nasociliary branch of the trigeminal nerve innervates both the cornea and the lateral dorsum of the nose as well as the tip of the nose
Holmes-Adie pupil
- large and irregular
- constriction to light is slow and incomplete
- accomodation is relatively normal
- once the pupil has constricted it remains small for an abnormally long time (tonic pupil)
What is Holmes-Adie syndrome?
The Holmes-Adie syndrome is the association of a Holmes- Adie pupil with absent deep tendon jerks.
• Clinical features include:
• unilateral in 80% of cases
• dilated pupil in early stages
• decreased consensual and direct light reflex
• tonic pupil: pupil slowly constricts in bright light
• decreased accommodation reflex
• decreased tendon reflexes
• hypersensitivity to G pilocarpine solution (0.12%)
• patients are often young women
Argyll Robertson Pupil
Signs of tertiary syphilis
Small, irregular, reacts to near stimulus only
- The Argyll Robertson pupil is usually bilateral and characterised by:
- small, irregular pupils
- the size of the pupils may be unequal
- absence of the light reflex
- a prompt accomodation reflex
- pupils slowly dilate with mydriatics
Can patients have eye features of Graves’ disease but normal thyroid function tests?
• Eye and orbital changes usually in association with
hyperthroidism - Graves’ disease
• Patient may be clinically and biochemically euthyroid -
ophthalmic Graves’ disease
Eye features of thyroid disease
• Exophthalmos (proptosis) • Grossly swollen extraocular muscles, esp. medial and inferior recti • Lid retraction and lid lag • May cause blindness - Optic nerve damage - Corneal perforation
Rheumatological conditions associated with dry eyes
Rheumatoid arthritis
Sjogren’s
Rheumatological conditions associated with (epi)scleritis
Mainly RA
Rheumatological conditions associated with Uveitis
- Behçet
- Sarcoidosis
- JIA
Rheumatological conditions associated with ophthalmic vascular occlusion
SLE
Rheumatological conditions associated with Orbital disease
Granulomatosis with
polyangiitis
What is Behçet’s Disease?
- Idiopathic multisystem disorder
- Occlusive vasculitis - eyes involved in 75%
- Presents in the 3rd and 4th decades
Diagnosis: Oral ulceration with two of • Recurrent genital ulceration • Skin lesions - folliculitis, erythema nodosum • Positive pathergy test • Eye involvement • Acute anterior uveitis • Vitritis, vasculitis, retinitis
Treatment for Behçet’s Disease?
systemic immunosuppression
What is Hypopyon?
Hypopyon is a medical condition involving inflammatory cells in the anterior chamber of the eye. It is a leukocytic exudate, seen in the anterior chamber, usually accompanied by redness of the conjunctiva and the underlying episclera.
Ophthalmic risks associated with Giant Cell Arteritis
• Risk of blindness from ischaemic optic neuropathy • Risk of systemic involvement including CVA • Often preceding history of amaurosis
What is Blepharitis?
• Ubiquitous seborroheic disorder of the meibomian glands • Causes mild ‘gritty’ sensation • Treated with lid hygeine ± oral tetracyclines
Ophthalmic risks associated with Stevens Johnson Syndrome
pseudomembranous conjunctivitis, cicatrisation of the
conjunctiva and lids
What is Herpes Zoster Ophthalmicus?
Shingles affecting CN V1
Multiple possible ocular complications: • Keratitis • Uveitis • Glaucoma
Require ophthalmic examination
What is Mucous Membrane Pemphigoid?
- Rare, idiopathic, chronic progressive, females>males
- Inflammation followed by scarring
Eye: 50-70% have eye involvement • Dry eye, symblepharon, ankyloblepharon, keratopathy • Treatment with topical and systemic steroids, immunosuppressants, contact lenses, lid surgery
Sturge-Weber Syndrome
- Rare congenital disorder
- Port-Wine Stain
- Seizures
- Mental Retardation
- 50% have glaucoma
Features that should raise suspicion of Chlamydial Conjunctivitis
• Conjunctivitis not improving
with treatment
• Pre-auricular lymphadenpathy
Treatment for Chlamydial Conjunctivitis
- Single dose azithromycin 1g
* Refer to GU
Ophthalmic complication of corticosteroids
• Posterior subcapsular
cataract
• Secondary glaucoma
Ophthalmic complication of (Hydroxy)Chloroquine
Maculopathy
Ophthalmic complication of Desferrioxamine
Maculopathy
Ophthalmic complication of tamoxifen
Maculopathy
Ophthalmic complication of Quinine
Optic atrophy, arteriolar
narrowing
Ophthalmic complication of Amiodarone
Corneal change
“Amiodarone Keratopathy”
Ophthalmic complication of Vigabatrin
Visual field loss
