Key points 23 Flashcards
Spasm of the near reflex can be distinguished from accommodative esotropia by:
near myopia
miosis on attempted lateral gaze
no vertical component
the angle of turn is highly variable and unpredictable
Which immunosuppressant has an enhanced effect with allopurinol?
Patients on allopurinol require a reduced dose of azathioprine.
The most common site of obstruction in acquired nasolacrimal obstruction is the:
The most common site of acquired nasolacrimal obstruction is the intra-osseous nasolacrimal duct. By contrast, in congenital obstruction, the most common site is the valve of Hasner.
Which treatment is most likely to be effective in multifocal choroiditis due to cryptococcus neoformans?
Cryptococcus neoformans is an encapsulated yeast. It is present in pigeon droppings and enters the body through inhalation. Infection usually occurs in patients with cell-mediated immune compromise (e.g. HIV). Ocular involvement usually occurs secondary to meningitis. Manifestations include papilloedema, ophthalmoplegia, optic neuropathy, nerve palsy, multifocal choroiditis, keratitis and conjunctivitis. Treatment is with: amphotericin, fluconazole and itraconazole.
What is the ROP screening criteria?
All babies <32 weeks gestation or less than 1501g birthweight should be screened for ROP
All babies less than 31 weeks gestational age or less than 1251g birthweight must be screened for ROP
What are the ocular features of Fabry’s disease?
vortex keratopathy, conjunctival aneurysms, posterior spoke-like cataracts, papilloedema, macular oedema, optic atrophy and retinal vascular dilation.
What are the ICG findings in PCV?
uncommon idiopathic choroidal vascular disease, characterised by typical ICG findings. The ICG shows a branching vascular network at the level of the choriocapillaris with polypoidal and aneurysmal dilatations at the terminals of the branching vessels beneath the RPE, which fill slowly and then leak intensely. The condition is characterised by serous PED with or without haemorrhage. Lesions occur at the macula most commonly, though peripapillary lesions are present in up to 20%. Asians are at increased risk.
The classification of scleritis most likely to present with visual loss is:
B-scan showing a sub-tenon’s effusion at the junction of the optic nerve and globe (T-sign).
Patients with posterior scleritis present with proptosis, pain, visual loss, and occasionally motility restrictions. Clinical findings include choroidal folds, papilloedema, exudative retinal detachment, and even angle-closure glaucoma are possible.
What is the Mizuo-Nakamura phenomenon
the appearance of a golden-brown fundus in the light adapted state with normalization of the colour on dark adaptation.
The electroretinogram in birdshot chorioretinopathy:
there are peripheral choroidal infiltrates, retinochoroidopathy and rod dysfunction. Scotopic responses on ERG are particularly affected, although photopic responses are also diminished. The b wave on ERG is disporportionately affected in birdshot.
Characteristics of manifest-latent nystagmus:
bilateral
becomes manifest and/or amplitude increases when one eye occluded, blurred or intermittently suppressed
jerk-type nystagmus
null point in adduction
fast phase towards fixing eye
face turn towards the fixing eye dampens nystagmus
associated with interruptions to binocular development: congenital esotropia, but also monocular congenital cataracts
A 6-year-old girl presents with unilateral blurred vision. On examination, you discover features in keeping with neuroretinitis with a swollen optic nerve and macular star.
What initial treatment would you offer?
Neuroretinitis can be idiopathic or it can be associated with viral infections (mumps, influenza, varicella) or other infections such as Cat-scratch and leptospirosis. The natural course is for spontaneous resolution over several months with excellent prognosis; observation is therefore appropriate initially.
The foramen rotundum transmits:
maxillary nerve and the small veins of the cavernous sinus.
A patient is sent to an ophthalmologist by a gastroenterologist to rule out Wilson’s disease. The most vital and sensitive aspect of the ophthalmologist’s examination is:
The earliest sign of copper deposition in Descemet’s membrane (Kayser-Fleischer ring) is detectable only at the far periphery with gonioscopy. Slit-lamp examination alone is insufficient.
Features suggesting a bilateral fourth nerve palsy are:
excyclodeviation over 10 degrees on double Maddox rod testing
a right hypertropia with right head tilt and left hypertropia with left head tilt
right hypertropia in left gaze and left hypertropia in right gaze
V pattern esotropia
chin down head position (no head tilt)
The two most commonly associated with bull’s-eye maculopathy are
cone dystrophy and Stargardt’s disease
An ICG in serpiginous choroidopathy is most likely to demonstrate:
Flourescein angiography of active lesions demonstrates early hypofluorescence (due to non-perfusion of choriocapillaris) and late hyperfluorescence due to staining. ICG of active lesions demonstrates hypofluorescence due to non-perfusion of choriocapilllaris, throughout the angiogram.
What are the features of Serpiginuous Choroidopathy?
Serpiginous choroidopathy is a rare, chronic, recurrent disease. It is usually bilateral, but often asymmetric. Presentation is with unilateral blurring of vision due to macular involvement. Signs include mild vitritis; active lesions are grey-white and located at the level of the RPE and inner choroid. Lesions occur firstly round the disc, from where they spread in a serpentine manner towards the macula and peripheral fundus. Inactive lesions are scalloped, atrophic, punched-out areas of chrorioretinal atrophy. The course of the disease lasts many years in an episodic, recurrent manner. Prognosis is poor with 50-75% of patients eventually developing visual loss in one or both eyes.
Compression gonioscopy with which contact lens is useful in distinguishing appositional angle closure from synechial angle closure?
Because of their smaller diameters, Zeiss, Sussman and Posner gonioscopy lenses may be used in indentation gonioscopy. This manoeuvre distinguishes appositional angle closure from synechial angle closure by artificially deepening the anterior chamber with digital pressure on the lens. Goldmann lenses and Volk 3-mirror lenses are too large for this and, in fact, by indenting the sclera they can shallow the anterior chamber with excessive pressure.
What are the characteristics of persistent hyperplastic primary vitreous
elongation of ciliary processes
prominent radial iris vessels
persistent hyaloid artery
microphthalmia
ectopia lentis
cataract
The risk of severe, life-threatening anaphylactic shock caused by fundus fluorescein angiography (FFA) is:
The risk of anaphylaxis from FFA has been quoted in the literature as between 1 in 350 FFA’s and 1 in 1900 FFA’s, depending on the study. The risk of severe, life-threatening anaphylaxis from FFA is less than 1 in 100,000 patients; with the risk of death quoted in one study as 1 in 220,000.
The rate of intraocular gas expansion is fastest for which gas:
SF6 has the highest expansile rate for any intraocular gas, which can cause dramatic spikes in IOP in the post-operative period.
What is the FFA finding in NAION vs GCA AAION
delayed optic disc filling present in 75% of NAION cases (whereas filling should be normal in optic neuritis)
Which pattern of nystagmus is most localising?
Seesaw nystagmus results from third ventricle tumors or diencephalic lesions (including parasellar/chiasmal lesions) involving the connections to the interstitial nucleus of Cajal (INC) and is therefore the most localising of those mentioned.
What causes upbeat nystagmus?
Lesions of the posterior fossa: including the anterior vermis and lower brainstem
Drugs
Wernicke’s encephalopathy
What causes downbeat nystagmus?
craniocervical junction lesions (e.g., Arnold-Chiari malformation)
intoxications (alcohol, lithium, phenytoin)
paraneoplastic syndrome
What causes periodic alternating nystagmus?
craniocervical junction
posterior fossa disease
