Thyroid Eye Disease (Graves' orbitopathy)

Features

•    Proptosis (exophthalmos)

•    Lid retraction ("stare"), lid lag on downgaze

•    Diplopia (due to extraocular muscle fibrosis; inferior rectus most commonly affected)

•    Exposure keratopathy

•    Compressive optic neuropathy (↓ colour vision, RAPD)

Risk Factors

•    Smoking

•    Uncontrolled hyperthyroidism

Management

•    Control thyroid dysfunction

•    Smoking cessation

•    Lubrication (mild cases)

•    IV steroids or orbital decompression (optic nerve compression)

Myotonic Dystrophy

Features

•    Bilateral ptosis

•    Early-onset cataracts (Christmas tree appearance)

•    Retinal pigmentary changes

•    Weakness, myotonia, frontal balding, cardiac conduction defects

Genetics

•    Autosomal dominant, CTG repeat expansion

Phacomatoses (Neurocutaneous syndromes)

NF1 (Neurofibromatosis type 1)

•    Lisch nodules (iris hamartomas, pigmented)

•    Optic gliomas → visual loss

•    Café-au-lait spots, neurofibromas

Tuberous Sclerosis

•    Retinal astrocytic hamartomas

•    Facial angiofibromas

•    Cortical tubers, subependymal nodules, renal angiomyolipomas

Sarcoidosis

Ocular Features

•    Anterior or posterior uveitis

•    Conjunctival granulomas

•    Lacrimal gland enlargement → dry eyes

•    Optic nerve involvement possible

Myasthenia Gravis

Features

•    Ptosis (fatigable) — worse as day progresses

•    Variable diplopia

•    No pupillary involvement (distinguishes from CN III palsy)

Diagnosis

•    Ice pack test: improves ptosis

•    AChR antibodies

•    Edrophonium (Tensilon) test (historical)

Diabetes Mellitus

Features

•    Diabetic retinopathy (NPDR, PDR)

•    Cataracts (earlier onset)

•    Cranial nerve palsies (III, IV, VI):

o    CN III palsy: pupil-sparing due to ischaemia

Hypertension

Features

•    Hypertensive retinopathy:

o    Silver/copper wiring

o    Cotton wool spots

o    Flame-shaped haemorrhages

o    Papilloedema (malignant HTN)

Extra Revision Pearls

•    Diplopia + proptosis clue → thyroid eye disease

•    Ptosis + cataracts clue → myotonic dystrophy

•    Lisch nodules clue → NF1

•    Retinal astrocytoma clue → tuberous sclerosis

•    Ptosis that improves with rest clue → myasthenia gravis

•    Pupil-sparing third nerve palsy clue → diabetes microvascular ischaemia

•    Cotton wool spots clue → diabetes or hypertension