Ophthalmology

Question 1

OD vs OS

Answer 1

OD (oculus dexter) right eye
OS (oculus sinister) left eye
OU (oculus uterque) both eyes

Question 2

Explain how to interpret snellen chart results

Answer 2

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.

Question 3

How should visual acuity be measured if visual acuity is 20/40 or less in one or both eyes?

Answer 3

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

Question 4

How is visual acuity tested if they are unable to see snellen chart from 3 or 1.5 m?

Answer 4

• Reduce distance to chart
• Count fingers
• Hand movement
• Light perception
• No light perception (NLP)

Question 5

Marcus Gunn pupil

Answer 5

afferent pupillary defect that can be detected with swinging torch test

affected eye has less response to light

Question 6

What are normal vs abnormal response on swinging-torch pupil examination?

Answer 6

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.

Question 7

What is a normal optic cup size?

Answer 7

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.

Question 8

Steps in Eye Examination

Answer 8

· 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.

Question 9

Presentations where eye examination is essential

Answer 9

• Headache
• Signs of raised ICP
• Malignant hypertension
• Sudden visual loss

Question 10

Important Nerves for eye examination

Answer 10

• II- Optic
• III- Oculomotor
• IV- Trochlear
• VI- Abducens

Question 11

Assessing the OPTIC (CN II) function

Answer 11

AFRO
• Acuity
• Fields
• Reaction
• ophthalmoscopy

Question 12

Causes of Relative Afferent Pupillary Defect

Answer 12

optic neuritis

advanced glaucoma

Question 13

Where is the lesion in a lower homonymous quadrantanopia?

Answer 13

lesion at left parental radiation

Question 14

Where is the lesion in a upper homonymous quadrantanopia?

Answer 14

lesion at left temporal radiation

Question 15

Causes of Eye movement disorders

Answer 15

• Brainstem disorders
• Cranial nerve palsies
• Hypertension, diabetes
• Intracranial aneurysm or cavernous sinus lesion
• Myasthenia gravis
• Muscle disease

Question 16

Symptoms of eye movement disorders

Answer 16

• Diplopia (III= complicated, IV= vertical, VI= horizontal)
• Others
• droopy eyelid, dilated pupil, neurological etc.

Question 17

What is binocular vs monocular diplopia?

Answer 17

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.

Question 18

Signs of third cranial nerve palsy

Answer 18

• Signs- “Down and out”
• Ptosis
• Pupil- may be dilated/ “blown out”

Question 19

Why would patient have dilated pupil in third nerve palsy?

Answer 19

parasympathetic fibres run along CN3

Question 20

Why would patient have ptosis in third nerve palsy?

Answer 20

CN III supplies levator palpebrae

Question 21

Causes of 4th CN nerve palsy

Answer 21

Very hard to pick up - Superior oblique isn’t working

• Trauma - susceptible due to long passage through cranial vault
• Congenital
• Ischemic (diabetic)
• SOL

Question 22

presentation of 6th CN nerve palsy

Answer 22

Eye can’t abduct past the midline

Question 23

Causes of 6th CN nerve palsy

Answer 23

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

Question 24

How can you differentiations between myasthenia graves eye features and CN palsy?

Answer 24

Myasthenia gravis can mimic any nerve palsy

But NEVER effects pupil

Question 25

Hutchinson's sign

Answer 25

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

Question 26

Holmes-Adie pupil

Answer 26

- 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)

Question 27

What is Holmes-Adie syndrome?

Answer 27

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

Question 28

Argyll Robertson Pupil

Answer 28

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

Question 29

Can patients have eye features of Graves' disease but normal thyroid function tests?

Answer 29

• Eye and orbital changes usually in association with hyperthroidism - Graves’ disease • Patient may be clinically and biochemically euthyroid - ophthalmic Graves’ disease

Question 30

Eye features of thyroid disease

Answer 30

``` • Exophthalmos (proptosis) • Grossly swollen extraocular muscles, esp. medial and inferior recti • Lid retraction and lid lag • May cause blindness - Optic nerve damage - Corneal perforation ```

Question 31

Rheumatological conditions associated with dry eyes

Answer 31

Rheumatoid arthritis | Sjogren's

Question 32

Rheumatological conditions associated with (epi)scleritis

Answer 32

Mainly RA

Question 33

Rheumatological conditions associated with Uveitis

Answer 33

* Behçet * Sarcoidosis * JIA

Question 34

Rheumatological conditions associated with ophthalmic vascular occlusion

Answer 34

SLE

Question 35

Rheumatological conditions associated with Orbital disease

Answer 35

Granulomatosis with | polyangiitis

Question 36

What is Behçet’s Disease?

Answer 36

* 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 ```

Question 37

Treatment for Behçet’s Disease?

Answer 37

systemic immunosuppression

Question 38

What is Hypopyon?

Answer 38

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.

Question 39

Ophthalmic risks associated with Giant Cell Arteritis

Answer 39

``` • Risk of blindness from ischaemic optic neuropathy • Risk of systemic involvement including CVA • Often preceding history of amaurosis ```

Question 40

What is Blepharitis?

Answer 40

``` • Ubiquitous seborroheic disorder of the meibomian glands • Causes mild ‘gritty’ sensation • Treated with lid hygeine ± oral tetracyclines ```

Question 41

Ophthalmic risks associated with Stevens Johnson Syndrome

Answer 41

pseudomembranous conjunctivitis, cicatrisation of the | conjunctiva and lids

Question 42

What is Herpes Zoster Ophthalmicus?

Answer 42

Shingles affecting CN V1 ``` Multiple possible ocular complications: • Keratitis • Uveitis • Glaucoma ``` Require ophthalmic examination

Question 43

What is Mucous Membrane Pemphigoid?

Answer 43

* 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 ```

Question 44

Sturge-Weber Syndrome

Answer 44

* Rare congenital disorder * Port-Wine Stain * Seizures * Mental Retardation * 50% have glaucoma

Question 45

Features that should raise suspicion of Chlamydial Conjunctivitis

Answer 45

• Conjunctivitis not improving with treatment • Pre-auricular lymphadenpathy

Question 46

Treatment for Chlamydial Conjunctivitis

Answer 46

* Single dose azithromycin 1g | * Refer to GU

Question 47

Ophthalmic complication of corticosteroids

Answer 47

• Posterior subcapsular cataract • Secondary glaucoma

Question 48

Ophthalmic complication of (Hydroxy)Chloroquine

Answer 48

Maculopathy

Question 49

Ophthalmic complication of Desferrioxamine

Answer 49

Maculopathy

Question 50

Ophthalmic complication of tamoxifen

Answer 50

Maculopathy

Question 51

Ophthalmic complication of Quinine

Answer 51

Optic atrophy, arteriolar | narrowing

Question 52

Ophthalmic complication of Amiodarone

Answer 52

Corneal change "Amiodarone Keratopathy"

Question 53

Ophthalmic complication of Vigabatrin

Answer 53

Visual field loss