Key points 5 Flashcards
The most common cause of acute, painful enlargement of the lacrimal gland is
Acute dacryoadenitis is most often caused by ascending staphylococcal infection and is associated with a purulent conjunctival discharge. Viral dacryoadenitis is frequently painless.
Which factors are Most important to the success of macular hole surgery?
Vitrectomy and ILM peeling are important in eliminating antero-posterior and tractional forces respectively, which are central to the pathophysiology of macular holes. Likewise, gas tamponade is important in creating a scaffold for hole closure. The role of posturing, however, is far less certain and remains a point of contention among surgeons. It is certainly the least important operative factor in the list above.
What are some fundus features of Eales Disease
Eales disease is an uncommon, bilateral, idiopathic, occlusive condition characterized by peripheral periphlebeitis and neovascularisation. It is more common in young Asian males and there is an association with tuberculoprotein hypersensitivity.
A child with congenital nystagmus has a null zone in right gaze and severe left head turn. Surgical intervention for the patient might include:
The goal of muscle surgery in congenital nystagmus is to move the null zone to primary position. This is done by shifting the resting position out of primary position toward the direction opposite to the null zone. Then, to obtain primary gaze, the child will need to innervate ocular muscles as if gaze were toward the null zone.
A 48-year-old woman presents with reduced right vision. On examination there is 360-degree peripheral choroidal effusion in the right eye. There is no past ocular history apart from hypermetropia. There is no tobacco dust and the IOP is 18mmHg.
What is the most appropriate management?
The patient in the question above has uveal effusion syndrome which is treated by sclerotomy down to the choroid to allow egress of the proteinaceous fluid. This is repeated in all four quadrants.
What is the most common site of retinoblastoma spread outside the eye?
Direct spread into the optic nerve and CNS is most common. Bone metastasis is seen in over half of metastatic cases. Lymph node metastases are the second most common type.
The single most important physical property of perfluorocarbon liquids rendering them useful as vitreous substitutes in vitreoretinal surgery is their:
The high specific gravity of perfluorocarbon liquids renders them heavier than water and makes them a useful addition to the vitreoretinal armamentarium. They can steamroll giant retinal tears flat, act as third hands in complicated surgery, and effect drainage of subretinal fluid through breaks in the far periphery, obviating the need for drainage retinotomies.
What are some disadvantages of using perfluorocarbon liquids in VR surgery?
they are not tolerated by the retina for >24 to 48 hours (histopathology shows compression of the retina) and they are not tolerated by anterior chamber structures at all.
From anterior to posterior the medial orbital wall is composed of:
maxilla, lacrimal bone, ethmoid, sphenoid
Which is the most common type of collagen in the sclera?
Type 1 collagen
Systemic side-effects of beta-adrenergic blockade include
central nervous system depression
syncope
bradycardia
Where is the lesion in dissociated divergence nystagmus?
posterior fossa lesions.
Where is the lesion in Downbeat nystagmus
craniocervical junction tumours, Wernicke’s, drugs (e.g. alcohol, lithium, phenytoin) and paraneoplastic syndromes (e.g. small cell lung cancer)
Where is the lesion in Upbeat nystagmus?
posterior fossa lesions, drugs and Wernicke’s.
Where is the lesion in See Saw nystagmus
parasellar/chiasmal lesions
Where is the lesion in gaze evoked nystagmus?
physiological, congenital motor nystagmus, posterior fossa (brainstem/cerebellar)
What is the diagnostic criteria for Behcet’s disease?
oral aphthous ulcers (any shape, size, or number at least 3 times in any 12 months period) along with 2 out of the following 4 hallmark symptoms:
genital ulcers: including anal ulcers and spots in the genital region and swollen testicles or epididymitis in men
skin lesions: papulo-pustules, folliculitis, erythema nodosum, pyoderma gangrenosum, acne in post-adolescents not on corticosteroids
eye inflammation: iritis, uveitis, retinal vasculitis, cells in the vitreous
pathergy reaction: papule >2 mm diameter 24-48 hrs or more after needle-prick. The pathergy test has a specificity of 95% to 100%, but the results are often negative in American and European patients.
Arteries vs Veins: Behcet disease and sarcoid which ones are involved?
Vasculitis in Behcet’s disease involves both arteries and veins, by contrast to sarcoid for example where ocular vasculitis only involves the veins (periphlebitis).
In which condition do we get crossed fibres at the chiasm?
tyrosinase-negative albinism
What are some ocular features of tyrosine negative albinism?
Crossed ON fibres at chiasm
V/A less than 6/60 due to foveal hypoplasia
Squints
Nystagmus
High refractive errors
What are the features of intermittent exotropia?
Amblyopia is not a feature of intermittent XT because the deviation is intermittent. Most patients with truly intermittent exotropia have excellent stereoacuity. High accommodative AC/A ratios may develop as a fusional mechanism for near work. The deviation in intermittent exotropia is highly variable and sensitive to external stimuli (stress, alcohol, tiredness). Bright light typically causes reflex closure of the deviating eye.
What are the duration of VR gases?
SF6: 10-14 days
C2F6: 30-35 days
C3F8: 55-65 days
What are 2 autosomal recessive conditions which present with albinism?
Hemansky-Pudlak and Chediak-Higashi
What blood test is abnormal in Hermansky Pudlak disease?
Abnormal platelets causing diathesis
What blood test is abnormal in Chediak Higashi syndrome?
leucocytes that cannot release enzymes from lysosomes causing recurrent pyogenic infections.
Which visual field best corresponds to a patient with acute papilloedema?
the visual field generally shows only an enlargement of the blind spot. The earliest loss of visual field in chronic papilloedema is typically in the inferior nasal quadrant.
What are the ERG findings in Birdshot Chorioretinopathy?
reduced b wave amplitude, decreased oscillatory potential, and delay in implicit time of 30Hz flicker (which is the most sensitive change).
What are ocular features of Lawrence Moon syndrome?
Lawrence-Moon syndrome is associated with retinal pigmentary changes, spastic paraplegia, hypogonadism and mental retardation.
Which type of basal cell carcinoma carries the worst prognosis?
The fibrosing (or sclerosing) type of BCC is also known as morpheaform. This pattern features strands of tumor cells infiltrating out from the central, clinically apparent lesion. Therefore, it is much more difficult to define the margins of the lesion. It is also less responsive to radiation therapy. The other forms listed above tend to be more localised.
A 4-year-old child is under paediatricians with aminoaciduria. There is developmental delay, hypotonia, abnormal skull shape and lamellar cataract bilaterally.
What is the most likely diagnosis?
Lowe syndrome is associated with:
X linked recessive inheritance
mental handicap
Fanconi syndrome of proximal renal tubules
muscular hypotonia
congenital cataract
microphakia
posterior lenticonus
What proportion of patients with sub-arachnoid haemorrhage have Terson’s syndrome?
33%
What is the CSMO criteria?
retinal thickening with 500 um of the fovea
hard exudates within 500 um of the fovea with associated retinal thickening
retinal thickening 1 disc area in size any part of which is within 1 disc diamter of the fovea
Which of the following syndromes is characterised by an anti-mongoloid slant of the palpebral fissure:
Treacher Collins is characterised by:
autosomal dominant
clefting syndrome
hypoplasia of the mid-face
pseudocolobomas of the eyelids
downward angle to the lateral canthi
micrognothia
dental anomalies
ear anomalies: small and malformed with conductive hearing loss
Which of the following is the most appropriate surgical treatment for acquired sixth nerve paresis with poor residual lateral rectus function:
The most widely accepted approach in sixth nerve palsy is a muscle-splitting operation utilising half of the superior and inferior rectus muscles in a transposition laterally (Jensen’s procedure).
In fluorescein angiography, pseudoautoflourescence occurs due to:
Pseudoautoflourescence occurs due to overlap in the spectral transmission of the excitation and barrier filters, meaning that some blue reflected light does pass through the barrier and appear as fluorescence.
What is the choice of stain for Acanthamoeba
Calcofluor white is the stain of choice for Acanthamoeba and requires fluorescence microscopy.
Causes of granulomatous uveitis?
syphilis (VDRL), sarcoid (ACE), TB (Tuberculin/purified protein derivative/PPD) among other aetiologies.
The prevalence of HLA-B27 in the UK general population is approximately:
estimated at 8%.
ERG findings in LCA
Leber’s congenital amaurosis is a disorder of congenital blindness that often presents with a normal appearing fundus in the neonatal period. However, an ERG done at this time will show a severely attenuated or extinguished ERG.
Features of direct CCF?
arterio-venous communication
caused by communication between ICA and cavernous sinus (c.f. meningeal branches of ICA for indirect)
trauma responsible for 75% of cases - others spontaenous from age-related arteriosclerosis
presents days to weeks after head injury
high flow shunt
blood flows anteriorly into ophthalmic veins
raised episcleral venous pressure
ocular congestion
pulsatile proptosis - bruit and thrill
anterior segment ischaemia
ophthalmoplegia
disc swelling, retinal haemorrhages
open angle glaucoma
not life-threatening but sight-threatening
Treatment: await spontaenous thrombosis OR balloon occlusion of fistula
The b wave of the ERG is formed by:
Bipolar cells
The extraocular muscle with the shortest length of active muscle belly is the:
The belly of the superior oblique is approximately 32 mm (the others are 37 to 40 mm)
What is the Bonferroni correction?
the Bonferroni correction is used to reduce the chance of a Type I error
A variant of Guillain-Barre syndrome that involves mainly the brainstem and cranial nerves is known as:
Miller Fisher syndrome, which is a variant of Guillan-Barre syndrome, is characterised by:
ophthalmoplegia
ataxia
areflexia
descending paralysis (as opposed to GBS where it is ascending)
positive anti-GQ1b antibodies in 90%
treatment by plasmapheresis and iv immunoglobulin
Name some ocular conditions with cataracts associated with urinary features
galactosaemia: reducing substance in urine
Lowe’s: aminoaciduria
Fabry’s: sediments
Wilson’s: copper
Alport’s: blood (glomerulonephritis)
Features of VHL
autosomal dominant inheritence
retinal capillary haemangioma
CNS haemangioma
cysts of kidneys, pancreas and ovaries
renal cell carcinoma
phaeochormocytoma
What is the Quickert procedure?
combines horizontal lid shortening with a transverse lid split and everting sutures, and would be the procedure of choice in this case.
What is the Wies procedure
involves a horizontal lid split and everting sutures, but it does not address the issue of horizontal lid laxity.
What is the Jones procedure
involves plication of the lower lid retractors, but once again, unless combined with another procedure, the Jones procedure does not address the issue of horizontal lid laxity
When is tarsal fracture done?
reserved for cicatricial entropion
Which arteries make up the circle of willis
Anterior cerebral arteries
Anterior communicating artery
Internal carotid arteries
Posterior cerebral arteries
Posterior communicating arteries
Features of Goldenhar syndrome
preauricular appendages
aural fistulas
maxillary or mandibular hypoplasia
hemifacial microsomia
vertebral deformities
lid coloboma
Duane’s syndrome
limbal dermoids
sensorineural deafness
The finding most frequently associated with degenerative retinoschisis is:
peripheral cystoid degeneration
A 7-year-old boy presents via his opticians with visual acuity of 6/6 right eye; 6/15 left eye. Motility is full, and there is no apparent tropia on cover-uncover testing. The child has stereoacuity of 120 seconds of arc. Distance Worth four-dot testing reveals fusion. Convergence and divergence amplitudes are normal at distance. There is no movement detected when a 4-prism dioptre is placed over the left eye.
What additional finding is MOST likely:
The clinical features of mild amblyopia, mildly impaired stereopsis, peripheral fusion, eccentric fixation with a central suppression scotoma are typical of a microtropia (the tropia is either too small to detect or does not exist because of parafoveal fixation and anomalous retinal correspondence). Microtropia is most common in the setting of anisometropia, usually hypermetropic anisometropia. Microtropia can also occur after (almost) successful strabismus surgery where the child controls to a microtropia.
Which of the following features in the history of a patient with a lacrimal gland mass is MOST important in determining aetiology?
The most helpful features in discriminating lacrimal gland masses are:
pain: more typical of acute inflammatory, infectious, or malignant lesions
onset: slow onset suggests a benign lesion, acute suggests inflammation or malignancy
bony erosion: favours a malignant lesion
