Ophthalmology Flashcards
What is glaucoma usually attributed to?
Glaucoma is a group of disorders characterised by Optic Neuropathy and is (usually) due to raised intraocular pressure.
What causes the increased intraocular pressure in Acute Angle-Closure Glaucoma (AACG)?
Increased intraocular pressure due to an impairment of aqueous outflow.
What 3 factors predispose a patient to Acute Angle-Closure Glaucoma?
- Hypermetropia (long-sightedness)
- Pupillary dilatation
- Lens growth associated with age
List the features of Acute Angle-Closure Glaucoma.
- Severe pain: may be ocular or a headache
- Decreased visual acuity
- Symptoms worse with mydriasis (dilatation of the pupil) eg. watching TV in a dark room
- Hard, red eye
- Haloes around lights
- Semi-dilated non-reacting pupil
- Corneal oedema results in a dull or hazy cornea
- Systemic upset may be seen eg. nausea, vomiting, abdominal pain.
What is the management of a patient with Acute Angle-Closure Glaucoma?
- Urgent referral to an Ophthalmologist
- Acetazolamide: Reduces aqueous secretions
- Topical Pilocarpine: induces pupillary constriction
What is the mode of action of Pilocarpine?
Muscarinic receptor agonist.
Pilocarpine is used in patients with Acute Angle-Closure Glaucoma. It increases Uveoscleral outflow by constricting the pupil (thereby decreasing intraocular pressure).
List 4 features of Horner’s syndrome.
- Miosis (small pupil)
- Ptosis
- Enophthalmos (sunken eye) **
- Anhydrosis (loss of sweating on one side)
** in reality, the appearance is due to a narrow palpebral aperture rather than true enophthalmos.
How would you know when a patient has congenital Horner’s syndrome?
Heterochromia (difference in iris colour) is seen in congenital Horner’s.
A central lesion is causing Horner’s syndrome. Where would you expect to see anhidrosis?
- Face
- Arms
- Trunk
A central lesion is causing Horner’s syndrome. List 5 possible differentials for the central lesion.
- Stroke
- Syringomyelia
- Multiple Sclerosis
- Tumour
- Encephalitis
A pre-ganglionic lesion is causing Horner’s syndrome. Where would you expect to see anhidrosis?
- Face
A pre-ganglionic lesion is causing Horner’s syndrome. List 4 possible differentials for the pre-ganglionic lesion.
- Pancoast’s Tumour
- Thyroidectomy
- Trauma
- Cervical rib
A post-ganglionic lesion is causing Horner’s syndrome. Where would you expect to see anhidrosis?
No anhidrosis.
A post-ganglionic lesion is causing Horner’s syndrome. List 4 possible differentials for the lesion.
- Carotid artery dissection
- Carotid aneurysm
- Cavernous sinus thrombosis
- Cluster headache
Describe a ‘Relative Afferent Pupillary Defect (RAPD)’.
What is the name given to a RAPD pupil?
RAPD: when the affect and normal eye appear to dilate when light is shoe on the affected eye.
Marcus-Gunn pupil.
What causes a Relative Afferent Pupillary Defect?
RAPD: caused by a lesion anterior to the Optic Chiasm ie. Optic Nerve or Retina
- > RAPD is caused by differences between the two eyes in the afferent pathway due to retinal or optic nerve disease.
- > This leads to reduced constriction (hence appears as dilation) of both pupils when light is shone from the unaffected eye to the affected eye.
How is a Relative Afferent Pupillary Defect identified?
Found by the ‘Swinging Light Test’.
What are the i. Retinal and ii. Optic Nerve causes of a Relative Afferent Pupillary Defect?
i. Retinal: Detachement
ii. Optic Nerve: Optic Neuritis eg. Multiple Sclerosis
Describe the pathway of pupillary light reflex.
Afferent and Efferent
Afferent: Retina -> Optic Nerve -> Lateral Geniculate Body -> Midbrain
Efferent: Edinger-Westphal nucleus (midbrain) -> Oculomotor Nerve
List the ocular manifestations of Rheumatoid Arthritis and some differentiating features.
- Keratoconjunctivitis sicca (most common)
- Episcleritis (erythema)
- Scleritis (erythema + pain)
- Corneal ulceration
- Keratitis
List the iatrogenic ocular problems a person with Rheumatoid Arthritis might encounter.
- Steroid-induced cataracts
- Chloroquine retinopathy
Which feature differentiates scleritis from episcleritis?
Scleritis = PAINFUL
Episcleritis = is not painful
Describe 4 features of Keratoconjunctivitis sicca.
- Usually bilateral
- Dry eyes
- Burning
- Itchy
Roughly what percentage of people with Rheumatoid Arthritis experience eye problems?
25%
What would you expect to see on fundoscopy of a patient with Retinitis Pigmentosa?
Black bone spicule-shaped pigmentation in the peripheral retina
What visual changes are associated with Retinitis Pigmentosa?
- Night blindness (often the initial sign)
- Tunnel vision (due to loss of the peripheral retina)
On fundoscopy: black bone spicule-shaped pigmentation in the peripheral retina, and mottling of the retinal pigment epithelium
Which diseases are associated with Retinitis Pigmentosa?
- Refsum disease: cerebellar ataxia, peripheral neuropathy, deafness, ichthyosis
- Usher syndrome
- A-beta-lipoproteinemia
- Lawrence-Moon-Biedl syndrome
- Kearns-Sayre syndrome
- Alport’s syndrome
A 71yo male with T2DM and hypertension is complaining of a sensation of lights flashing in his right eye. Symptoms have been present for 2 days and seem to occur more at the periphery of his vision. There is no pain or redness in the affected eye.
Corrected visual acuity is measured as 6/9 in both eyes.
What is the most likely diagnosis?
Vitreous detachment
Flashers and floaters are symptoms of vitreous detachment. The patient is at risk of retinal detachment and should be referred urgently to an Ophthalmologist.
What are the most common causes of sudden, painless loss of vision?
- Ishcaemic / vascular: eg. thrombosis, embolism, temporal arteritis). This include syndromes such as Occlusion of central retinal vein and Occlusion of central retinal artery.
- Vitreous haemorrhage
- Retinal detachment
- Retinal migraine
What are the differentials for sudden painless loss of vision with an ischaemic / vascular cause?
- ‘Amarosis fugax’
- Atherothrombosis
- Embolus
- Dissection
- Small artery occlusive disease eg. Anterior ishcaemic optic neuropathy, vasculitis (temporal arteritis)
- Venous disease
- Hypoperfusion
- May represent a form of Transient Ischaemic Attack
What causes Ischaemic Optic Neuropathy?
- Occlusion of the short posterior ciliary arteries
- Causes damage to the Optic Nerve
For Central Retinal Vein Occlusion, describe the following:
i. Incidence
ii. Causes
iii. What you’d see on fundoscopy.
Central Retinal Vein Occlusion
i. Incidence increases with age. More common that arterial occlusion.
ii. Causes: Glaucoma, Polycythaemia, Hypertension
iii. Fundoscopy: Severe retinal haemorrhages
For Central Retinal Artery Occlusion, describe the following:
i. Cause
ii. Features
Central Retinal Artery Occlusion
i. Cause: due to thromboembolism (from atherosclerosis) or arteritis (eg. temporal arteritis)
ii. Features:
- Afferent pupillary defect
- ‘Cherry red’ spot on a pale retina
For Vitreous Haemorrhage, describe the:
i. Causes
ii. Features
Vitreous Haemorrhage
i. Causes: Diabetes, Bleeding Disorders, Anticoagulants
ii. Features: sudden visual loss, dark spots
How would you identify Posterior Vitreous Detachment from a patient’s symptoms?
- Flashes of light (photopsia) in the peripheral field of vision
- Floaters, often on the temporal side of the central vision
How would you identify Retinal Detachment from a patient’s symptoms?
- Dense shadow that starts peripherally and progresses towards the central vision
- A veil or curtain over the field of vision
- Straight lines appear curved
- Central visual loss
How would you identify a Vitreous Haemorrhage from a patient’s symptoms?
- Large bleeds cause sudden visual loss
- Moderate bleeds may be described as numerous dark spots
- Small bleeds may cause floaters.
What is ‘Posterior Vitreous Detachment’?
The separation of the vitreous membrane from the retina.
This occurs due to natural changes to the vitreous fluid of the eye with ageing.
- A common condition which does not cause any pain or loss of vision.
Which condition is it important to rule out in a patient with Posterior Vitreous Detachment?
Rule out Retinal tears or Retinal Detachment as this may result in permanent loss of vision.
-> separation of the vitreous membrane can lead to tears and detachment of the retina.
What is ‘Hutchinson’s sign’? What does it predict?
The presence of a vesicular rash on the tip of a patient’s nose.
Predicts ocular involvement eg. consider Herpes Zoster Ophthalmicus.
Which virus causes Herpes Zoster Ophthalmicus?
Varicella-Zoster Virus
Reactivation of VZV in the area supplied by the ophthalmic division of the trigeminal nerve.
What are the features of Herpes Zoster Ophthalmicus?
- Vesicular rash around the eye, which may or may not involve the actual eye itself.
- Hutchinson’s sign: rash on the tip or side of the nose. Indicates nasociliary involvement and is a strong risk factor for ocular involvement.
Describe the management of Herpes Zoster Ophthalmicus.
- Oral antiviral treatment for 7-10 days
> Ideally started within 72 hours
> IV antivirals may be given for very severe infection or if the patient is immunocompromised.
> Topical antiviral treatment is NOT given in HZO. - Topical corticosteroids may be used to treat any secondary inflammation of the eye
- Ocular involvement requires urgent ophthalmology review.
What are the complications of Herpes Zoster Ophthalmicus?
- Ocular: conjunctivitis, keratitis, episcleritis, anterior uveitis
- Ptosis
- Post-herpetic neuralgia
What is Blepharitis?
Inflammation of the eyelid margins.
What causes Blepharitis?
- Posterior blepharitis is caused by Meibomian gland dysfunction (this is most common)
- Anterior blepharitis (less common) is caused by seborrhoea dermatitis / staphylococcal infection.
- Blepharitis is also more common in patients with rosacea.
How do problems affecting the Meibomian glands lead to blepharitis?
- Meibomian glands secrete oil onto the eye surface to prevent rapid evaporation of the tear film.
- Any problem affecting the Meibomian glands (as in Blepharitis) can hence cause drying of the eyes which in turn leads to irritation.
What are the features of Blepharitis?
- Symptoms are usually bilateral
- Grittiness and discomfort, particularly around the eyelid margins
- Eyes may be sticky in the morning
- Eyelid margins may be red. Swollen eyelids may be seen in staphylococcal blepharitis
- Styes and chalazions are more common in patients with blepharitis
- Secondary conjunctivitis may occur
Describe the management of a patient with Blepharitis.
- Softening of the lid margin using hot compresses twice a day
- ‘Lid hygiene’: mechanical removal of debris from lid margins
> cotton wool buds dipped in a mixture of cooled boiled water and baby shampoo
> OR a teaspoonful for sodium bicarbonate in cooled water that has recently been boiled. - Artificial tears may be given for symptom relief in people with dry eyes or an abnormal tear film.
