Key points 20 Flashcards
In young children, anterior polar cataracts are typically:
Anterior polar cataracts are usually bilateral and usually do not impair vision. They are typically static. Anterior polar cataracts may occur sporadically, in association with other anterior segment anomalies or may be inherited in an autosomal dominant fashion.
Where is the connection in direct CCF
Direct CCF are caused by a connection between the internal carotid artery (ICA) and the cavernous sinus.
Where is the connection in indirect CCF
meningeal branches of ICA to cavernous sinus
meningeal branches of external carotid artery to cavernous sinus
meningeal branches of both the ICA and ECA to the cavernous sinus
Adie vs Arygll Robertson pupil?
Argyll-Robertson pupils are usually bilateral but may be asymmetrical. They are caused by a lesion in the dorsal midbrain affecting the light-reflex fibres but sparing the near-response fibres. While traditionally associated with syphilis, they can also be caused by diabetes, MS, trauma, surgery, alcohol and aberrant 3rd nerve regeneration. Typically Argyll-Roberston pupils do not dilate well to mydriatics such as tropicamide or cocaine 4-10%.
Adie’s tonic pupil, which can also cause light-near dissociation. While usually enlarged, an Adie’s pupil (especially if longstanding) can be small. However, the hallmark feature of Adie’s is a slow, gradual constriction on near response, with a similarly slow re-dilatation on relaxing accommodation, which was not described in this case. Adie’s pupils are also usually unilateral (not bilateral) and there is super-sensitivity to dilute pilocarpine 0.1%.
Bipolar cell bodies lie in which layer of the retina:
Bipolar cell bodies are found in the inner nuclear layer.
Recurrence of disease has been reported following penetrating keratoplasty for each of the following indications except:
Unless the donor endothelium is unhealthy (which is unlikely due to eye bank analysis of all donor material before distribution) or the donor tissue is damaged at the time of surgery (primary graft failure), the findings of Fuchs’ dystrophy do not recur.
Ischaemia due to occlusion of a calcarine artery would be expected to produce what visual field defect?
Ischaemia to a calcarine artery produces a congruous defect (more posterior the defect, more congruous) and there is often macular sparing because of anastomoses between the middle and posterior cerebral arteries at the very pole, where the macular fibres terminate.
Fluorescein angiogram findings in multiple evanescent white dot syndrome (MEWDS) include
FFA in MEWDS is characterized by early punctate hyperfluorescence, often in a wreath-like configuration. This is followed by late staining of the same punctate areas. Late disc staining is also a feature.
In A-scan biometry, a one diopter IOL power error could result from an axial length error of:
0.4mm compression error can result in a 1 diopter error in the calculated IOL power.
What would fluorescein angiography most likely show in a patient with a macular hole?
The RPE beneath a macular hole may undergo atrophy leading to hyperfluorescence from a window defect.
A bilateral inferior oblique myectomy to correct a V-pattern exotropia, can be expected to yield how much esodeviation in upgaze?
A bilateral inferior oblique myectomy produces 15 to 25 prism diopters of esodeviation in upgaze (to correct a V pattern).
A bilateral superior oblique tenotomy causes 40 prism dioptres of esodeviation in downgaze (to correct an A pattern).
An 85-year-old lady with dementia who resides in a nursing home is asymptomatic but is found to have a dome-shaped, elevated, pigmented lesion in the mid-periphery of the right fundus. The lesion is 8 mm in diameter and 3 mm thick.
What is the most suitable treatment?
The appearances are highly suggestive of a large choroidal melanoma. The ideal treatment is enucleation. However, this lady is very elderly and has co-morbidities with a limited life expectancy. It is most appropriate, given the patient factors specific to this case, to observe the lesion for progression initially, since there will be difficulty adhering to treatment and follow-up - and limited benefit in terms of long-term quality of life.
Which conditions present with diffusely distributed keratic precipitates
Fuchs’ heterochromic iridocyclitis
sarcoidosis
syphilis
toxoplasmosis (rarely)
What are the fundus findings in High risk proliferative diabetic retinopathy
NVD greater than 1/3 disc area
NVD of any size with vitreous haemorrhage
NVE greater than 1/2 with vitreous haemorrhage
Which of the following treatments is indicated for Pneumocystic carinii?
Treatment includes trimethoprim/sulfamethoxazole (Bactrim), atovaquone, pentamidine, or dapsone.
The treatment of choice for the most common cause of chronic canaliculitis is:
Actinomyces israelii is a Gram-positive, branching, filamentous bacterium and is the most common cause of canaliculitis. Medical therapy includes warm compressors, digital massage and topical antibiotics but they are rarely curative alone. Actinomyces israelii is usually found and treated with expression and curettage of the canaliculus.
A 38-year-old lady is found to have mid-peripheral yellowish flecks in both eyes. A fluorescein angiogram reveals a silent choroid.
Which of the following electrophysiologic findings is characteristic of this condition?
The case description is characteristic of Stargardt’s disease. Electrophysiological testing in Stargardt’s is often not helpful. Pattern ERG and EOG responses may be sub-normal; but ERG responses are certainly not extinguished and EOG light peak to dark trough is not profoundly reduced.
What is the triad of INO?
failure of ipslateral adduction (often best seen with saccades)
ataxic nystagmus of abducting contralateral eye
normal convergence (if posterior INO)
What is the average time to onset of action of botulinum toxin?
Average onset is 2 to 3 days. Peak effect usually occurs 2 to 3 weeks after injection.
What are the features of amblyopia?
reduced Snellen acuity by 2 lines
reduced visual acuity with crowded letters compared to single optotypes
decreased contrast sensitivity
binocular suppression
eccentric fixation
prolonged perception and reaction times to a stimulus
no RAPD, no VF defect
A 78-year-old lady with a macular hole has difficulty posturing on account of osteoarthritis. What concentration of C3F8 gas would you use following vitrectomy?
C3F8 expands 4 times its volume at 100% concentration and lasts 8 weeks. The non-expansile concentration used in vitrectomy is between 12-16% with air.
SF6 doubles its volume in 2 days and lasts for 2 weeks. Its non-expansile concentration is between 20-30% with air.
A patient presents with gradual reduction in visual acuity. He is a high hypermetrope and his corneal diameter is 11 mm. On B-scan ultrasound there are dome-shaped posterior segment elevations.
What treatment is most likely to be effective for this condition:
This is the uveal effusion syndrome which is predisposed in small, microphthalmic or nanophthalmic eyes. The most definitive treatment is the creation of scleral windows for drainage of supra-choroidal effusions.
Which is the most appropriate imaging modality for a patient with a suspected exacerbation of thyroid eye disease?
T2 weighted STIR sequences are best for delineating thyroid activity. T2 allows evaluation of activity in the extraocular muscles while STIR suppresses orbital fat allowing excellent visibility of adjacent structures.
Causes of microspherophakia include:
Microspherophakia, as its name implies, is characterized by a lens with small diameter and a spherical shape. High myopia is often found in association. It may occur as an isolated hereditary disorder or in association with other abnormalities - most commonly Weill-Marchesani syndrome.
Weill-Marchesani syndrome
Alport’s syndrome
Marfan’s syndrome
Peter’s anomaly
Congenital rubella
Which cataract is classically associated with myotonic dystrophy?
Christmas-tree cataract (a polychromatic crystalline needle-like opacity in the deep cortex and nucleus) is associated with myotonic dystrophy. It occurrs in up to 90% of these patients. While visually insignificant, Christmas-tree cataract may progress in later life in patients with myotonic dystrophy to stellate posterior subcapsular cataract.
What are characteristic findings in infantile esotropia
large angle esotropia, usually greater than 30 PD
onset usually during the first few months, by definition by 6 months of age
cross-fixation may be present
latent nystagmus
dissociated vertical deviation (in up to 60%-70%)
inferior oblique overaction with V-pattern esotropia (in up to 60%-70%)
mild hyperopia, + 1.00 to + 2.00 D
What is the most common cause of communicating hydrocephalus?
SAH
caused by impaired CSF re-absorption in the absence of any CSF flow obstruction between the ventricles and subarachnoid space. This is due to functional impairment of the arachnoid granulations, which are located along the superior sagittal sinus and are the site of CSF re-absorption back into the venous system
What conditions cause a large angle kappa
ROP
FEVR
combined hamartoma of RPE and retina
persistent posterior fetal vasculature
The superior oblique inserts on which quadrant of the globe:
The superior oblique inserts on the posterosuperior quadrant of the globe.
