Key Points 8 Flashcards
Features of homocystinuria?
pale hair (blond or red)
autosomal recessive inheritance
osteoporosis
increased risk of thrombo-embolic events
mental retardation
downward lens subluxation with absent zonules and accomodation
Melanomalytic glaucoma is caused by:
blockage of the trabecular meshwork by macrophages that have engulfed material released from an intra-ocular melanoma tumor.
What are the characteristics of Argyll Robertson pupils?
small and irregular pupils
bilateral
light-near dissociation (pupils respond to near, not light)
caused by syphilis, but also DM, trauma, degeneration, alcohol, MS
tends to occur in the elderly
normal time for pupil constriction, dilation and accommodation (unlike a tonic pupil)
pupils do not respond to cocaine 4-10%
Approximately what percentage of patients with documented candidaemia develop candida endophthalmitis, defined as at least some degree of vitreous inflammation?
Approximately 10% of patients with candidaemia ultimately develop candida endophthalmitis. Earlier series documented rates approaching 40%, but these studies defined virtually every fundus finding as endophthalmitis, including nonspecific retinal vascular changes such as Roth’s spots and nerve-fiber layer infarcts. The distinction is important because chorioretinal involvement without vitreous infection will respond to system antifungals, obviating the need for vitrectomy and/or intravitreal antibiotics. The reason for the lack of vitreous involvement is presumably the response to systemic antifungal agents.
A ray of light parallel to the principal axis of a thin lens will:
A ray of light parallel to the principal axis of a thin lens will be refracted through the focal point of the lens. It is an important principal in the construction of ray diagrams, as for any object, one can predict the image produced by drawing 2 lines (a) one passing through the nodal point undeviated, (b) the other parallel to the principal axis passing through the principal focus.
A patient presents for review 1 month post-trabeculectomy for primary open angle glaucoma. On examination, IOP is 4mmHG and the anterior chamber is shallow. The bleb is cystic and avascular. The Seidel test shows sweating.
What treatment option is MOST likely to be effective:
This patient has late bleb leakage. This is managed initially as for early overfiltration, including aqueous suppressants and conjunctival tamponade (eg bandage contact lens) but these measures are rarely effective. Other treatment depends on if there is ‘sweating’ or a true conjunctival buttonhole. Sweating is treated by autologous blood injection and compression sutures. Button-holes require revisional surgery such as conjunctival advancement or conjunctival autograft.
What is the typical ERG finding in melanoma-associated retinopathy?
The auto-antibodies produced in melanoma-associated retinopathy appear to have activity against bipolar cells, which is correlated with ERG findings which show mark reduction in dark- and light- adapted b waves, with preservation of the a-wave. This configuration is called a negative ERG (also found in congenital stationary night blindness).
What is the criteria for plus disease in ROP?
The specific criteria for plus disease is increased venous dilatation and arteriolar tortuosity of the posterior retinal vessels in at least two quadrants of the eye.
Plus disease is often accompanied by other signs:
failure of the pupil to dilate with iris vessel engorgement
vitreous haze
increasing preretinal and vitreous haemorrhage
A 24-year-old rugby player complains of intermittent diplopia since a rugby tackle 2 weeks ago. On examination, he has a right hypertropia worse on left gaze and improved by left tilt. Cover-uncover testing shows no shift but alternate cover test shows a deviation neutralized with 13 PD base down prism in front of his right eye.
What can this patient be told about his condition?
Vertical fusion amplitudes are useful for distinguishing congenital from acquired fourth nerve palsies. Normal vertical fusion amplitudes are 3 to 5 PD. In congenital (longstanding) IV palsy, patient can develop amplitudes of 10 to 25 PD. This patient has a right hyperphoria of 12 PD; this means that the vertical fusion amplitude is at least 12 PD, indicating a long-standing deviation. Although trauma is the most common cause of acquired IV palsy, it is also (often coincidentally) the trigger that allows congenital palsies to be manifest. In addition to increased vertical fusion amplitudes, these patients may have a head tilt to the contralateral side to reduce the hypertropia. Old photographs may be helpful in demonstrating this feature.
Wedl bladder cells are found in:
In posterior subcapsular cataract there is posterior migration of lens epithelial cells, which swell to become Wedl or bladder cells.
Features of Map Dot fingerprint dystrophy?
bilateral condition
can be dominantly inherited
clinical findings: cystic, geographic, or fingerprint formations
best seen with sclerotic scatter or retroillumination
histopathology: thickened basement membrane, abnormal epithelial cells with microcysts, and fibrillar material between the basement membrane and Bowman’s layer
symptoms typically occur between the fourth and sixth decades
treatment options: topical lubricants, 5% sodium chloride, scraping, patching, anterior stromal puncture, or possibly phototherapeutic keratectomy
A patient presents with bilateral sixth nerve palsy. Where is the most likely location of nerve compression?
The clivus
Is MEWDS uni or bilateral?
unilateral
Features of pellucid marginal degeneration
bilateral condition
non-hereditary
non-inflammatory degeneration of peripheral cornea
onset usually 20 to 40 years of age
affects both men and women equally
thinning of cornea inferiorly
protrusion of the cornea above the area of maximal thinning inferiorly
no corneal vascularization or lipid deposition
vision is decreased due to irregular astigmatism
irregular, against-the-rule astigmatism
treatment: contact lenses and penetrating keratoplasty
A patient has a 2mm ptosis due to longstanding Horner’s syndrome. What is the most appropriate treatment?
A tarsomullerectomy (Fasanella servat procedure) involves resection of Muller’s muscle and a strip of tarsal plate and conjunctiva by a transconjunctival approach. It is useful for mild ptosis (2mm), such as that associated with Horner’s syndrome. Larger degrees of ptosis require aponeurotic repair, levator resection or (for maximal repair) frontalis sling.
Examples of Trinucleotide repeat disorders
Fragile X
Myotonic dystrophy
Huntington chorea
Friedreich ataxia
Spinocerebellar ataxia
Spinobulbar muscular atrophy
Machado-Joseph ataxia
What is the EOG finding in best disease?
Best disease is most reliably diagnosed by EOG, where there is a reduction in the light peak to dark trough ratio (Arden ratio).
What are the features of Blepharophimosis syndrome?
congenital condition
autosomal dominant inheritance (known as the Kohn-Ramono syndrome)
widened intercanthal distance (telecanthus)
ptosis
blepharophimosis
epicanthus inversus
associated findings:
lower eyelid ectropion is commonly seen
poor development of the orbital rims and nasal bones
hypertelorism
systemic: primary amenorrhoea
The most common cause of third nerve palsy in the paediatric population is:
congenital
traumatic
inflammatory
migrainous
neoplastic
An anterior communicating artery aneurysm is most likely to produce what kind of VFD
most likely to compress the upper portion of the optic chiasm, producing a bitemporal lower quandrantanopia.
Rounded, gelatinous-appearing lesions of the conjunctiva with vessels at the periphery, but never within the nodular substance, are called:
follicles
What is Brown syndrome?
there is absence of ipsilateral superior oblique overaction, which helps to distinguish Brown’s syndrome from a paresis of the inferior oblique
Features of Brown syndrome?
congenital or acquired aetiology
inelastic superior oblique muscle tendon complex
restriction of passive or active elevation in adduction (including positive forced duction)
downshoot of the eye on adduction (but no superior oblique overaction)
no superior oblique overaction
V-pattern is common
rarely the eye may become hypotropic
rarely an abnormal head posture occurs with a tilt toward the affected side
Which nerve runs along the length of the inferior orbital fissure towards the lateral orbital wall:
The zygomatic nerve runs the length of the inferior orbital fissure towards the lateral orbital wall, where it pierces the zygoma as 2 branches: the zygomaticotemporal and zygomaticofacial nerves.
