Orbital apex syndrome

- a.k.a Jacod syndrome
- collection of cranial nerve deficits associated with a mass lesion near the orbital apex region
- presents with proptosis, chemosis, optic neuropathy, Horner's syndrome, ophthalmoplegia, involvement of ophthalmic nerve (first branch of trigeminal nerve)

Scleritis

- associated with RA, Wegener's granulomatosis, SLE, PAN, relapsing polychondritis
- redness of sclera and conjunctiva or dull purple area of inflammation, with severe deep boring pain, photophobia and loss of visual acuity
- scleritis may lead to perforation of eye (scleromalacia perforans)
- treatment: NSAIDs, steroids eye drops or if severe surgery is indicated

Foster Kennedy syndrome

- frontal lobe tumor (commonly meningioma in sphenoidal wings)
- causing ipsilateral disc atrophy (compression) + contralateral disc swelling (increased ICP)

Idiopathic intracranial hypertension

- a.k.a benign intracranial hypertension or pseudotumor cerebri
- most common in obese young women between age 20-50
- headache (worse with straining and bending forward), visual blurring with papilloedema are common features
- 4 diagnostic criteria must be met
  i) sign and symptoms of increased ICP
  ii) normal or small size ventricles seen on neuroimaging
  iii) increased CSF pressure with normal composition
  iv) papilledema
- associated factors: OCP, steroids, vitamin A, tetracycline, nitrofurantoin
- opening pressure on LP : >25cm water
- complication: optic nerve infarction or blindness
- treatment: repeated lumbar puncture, acetazolamide, thiazide diuretics, surgical decompression or shunting (lumboperitoneal shunt), trial of steroid for severe cases at risk of visual impairment due to papilloedema, optic nerve fenestration

Angioid streaks

- a.k.a Knapp streaks
- small break in Bruch's membrane
- brown, concentric snake like lines
- Associations
  - pseudoxanthoma elasticum
  - UGIB
  - middle ear deafness
  - IHD
  - PVD
  - floppy mitral valve
  - sickle cell disease
  - Paget disease
  - Ehler Danlos syndrome
- avoid contact sports as it can predispose to globe rupture

Junctional scotoma

- ipsilateral scotoma + contralateral superior quadrantanopia
- lesion at von Willebrand's knee / anterior optic chiasm (eg: meningioma)
- von Willebrand knee is inferonasal fibers of optic nerve which go into the contralateral optic nerve 4mm before crossing over to the opposite optic tract

Horner's syndrome

- unilateral pupillary constriction with slight ptosis and enophthalmos indicates a sympathetic pathway lesion on ipsilateral side
- diminution of sweating on the same side depends upon the level of lesion
  i) central lesion : entire half of head, arm and upper trunk
  ii) neck lesion proximal to superior cervical ganglion (preganglionic): diminished facial sweating
  iii) lesion distal to superior cervical ganglion (postganglionic) : do not affect sweating at all
- Iris heterochromia if congenital or long standing
- Tests
   i) 4% cocaine drop (Horner does not dilate)
  ii) 1% hydroxyamphetamine (post ganglionic Horner does not dilate)

CHRPE

- congenital hypertrophy of retinal pigment epithelium
- 'bear track' lesion
- can be typical or atypical
- typical: grey or black with depigmented lacunas and are found in one quadrant of one eye, do no affect vision
- atypical: white fishtail and bilateral. They do not affect vision but if they are more than 4 atypical CHRPE in each eye then FAP or Gardner syndrome might be suspected

Retinitis pigmentosa

- characterised by triad of
   - night blindness (loss of rod function)
   - tunnel vision (rod dysfunction)
   - pigmented 'bony spicules'

Important systemic associations
- Abetalipoproteinemia (Bassen Kornzweig syndrome)
- Refsum's disease
- Usher syndrome
- Laurence Moon Biedl syndrome
- Kearns Sayre syndrome

Wilson's disease

- toxic accumulation of copper in the liver and CNS (basal ganglia) due to failure of biliary copper excretion
- autosomal recessive
- defective gene ATP 7B (chromosome 13)
- prevalence 3:100,000
- normal copper absorption but defetive intrahepatic formation of caeruloplasmin
- features
   - onset in childhood/adolescence
   - hepatic dysfunction (cirrhosis)
   - CNS involvement (chorea, oromandibular dystonia, tremor, seizure, cerebellar signs, psychosis)
   - Kayser-Fleischer ring (copper deposition in Descement membrane)
   - hemolysis
   - Fanconi syndrome
   - low serum uric acid
- diagnosis
   - decrease in serum caeruloplasmin
   - increase in hepatic copper content
   - increase urinary excretion of copper (further increase following administration of penicillamine)
- treatment: copper chelators (penicillamine and trientine), zinc

CMV retinitis

- without HAART, up to 30% of AIDS patients develop reactivation of CMV in the form of destructive and blinding retinitis
- slowly progressive disorder, visual loss may occur suddenly as a result of hemorrhage or retinal detachment
- presents with blurring of vision, scotoma, floaters and flashing lights
- patches of irregular retinal pallor and hemorrhage in perivascular distribution
- complications: retinal detachment, branch retinal artery occlusion, persistent iritis, cataract
- treatment: IV ganciclovir 10mg/kg/day for 3 weeks, foscarnet
 (ganciclovir is myelosuppressive, FBC should be monitored)

Holmes Adie syndrome

- Adie's pupil is due to postviral degeneration in ciliary ganglion 
   (where as in Argyll Robertson pupil is caused by damage to pathway from retina to Edinger Westphal   nucleus)

- tonically dilated pupil

-  does not constrict to light but constrict to accomodation
- pupil constricts with 0.125% pilocarpine (due to cholinergic denervation supersensitivity)

- Holmes Adie syndrome is combination of Adie's pupil and hyporeflexia

- also presents as diaphoresis, hyperopia (due to accomodative paresis)
- Ross's syndrome = Adie's syndrome + segmental anhidrosis (typically associated with compensatory hyperhidrosis)

microvascular cranial nerve palsy

- one of the most common causes of double vision in elderly with diabetes and hypertension
- a.k.a diabetic palsy
- occurs when perfusion to abducen, oculomotor or trochlear nerve is affected
- presented with diplopia, drooping eyelid or mydriasis
- benign prognosis
- treatment: eye patch, treat underlying diabetes and hypertension

Internuclear ophthalmoplegia (INO)

- In  INO, when the patient’s gaze is directed away from the side of the lesion, the ipsilateral (adducting) eye will not adduct and the contralateral (abducting) eye demonstrates horizontal nystagmus.
- Surprisingly, patients usually do not complain of diplopia
- lesion at medial longitudinal fasciculus (MLF)
- Causes:

• Multiple sclerosis —likely cause in adulthood/middle age; often bilateral. (bilateral INO is nearly pathognomonic of MS)
• Vascular brainstem lesion —likely cause in the elderly or people with vascular risk factors; often unilateral.
• Pontine glioma —more likely cause in children.
• Inflammatory encephalitis affecting the brainstem (e.g. autoimmune, infective)
• Myasthenia gravis (unusual)

- One and a half syndrome is internuclear ophthalmoplegia combined with a conjugate gaze paralysis in the other direction. One eye fails to adduct on attempted lateral gaze (‘the half’) and the other eye neither adducts nor abducts (‘the one’). The eye that can abduct may exhibit horizontal nystagmus when it does so. The responsible lesion is an extensive paramedian pontine lesion that involves the MLF and either the CN6 nucleus or the PPRF (parapontine reticular formation). Often ischemic.