Key points 19 Flashcards
What are Features of Parinaud’s dorsal midbrain syndrome:
light near dissociation
defective accommodation and convergence
upgaze palsy (supranuclear)
convergence retraction nystagmus
Collier’s sign (lid retraction on upgaze)
Skew deviation
Which retinal layer accounts for the petalloid appearance of cystoid macular oedema as seen in fluorescein angiography?
The radiating fibres of Henle in the outer plexiform layer lead to the cystic spaces in CMO.
Which Gram negative organism is commonly associated with angular blepharitis?
Moraxella is a well-established cause of angular blepharitis.
Which of the following statements most accurately describes the conclusion reached by the DRS study:
early PRP reduces the rate of severe sight loss particularly in high-risk PDR
Which of the following findings on CT imaging is most helpful in differentiating orbital pseudotumour from thyroid eye disease:
Pseudotumour unlike TED can and commonly does involve the muscle tendons as well as their insertions, along with the posterior Tenon fascia and sclera. Besides these findings, the two conditions may be virtually indistinguishable on imaging.
What are the central Estermann field requirements for driving?
Regarding central visual field, the following are unacceptable:
a cluster of 4 or more adjoining points either wholly or partly within central 20 degrees
loss consisting of both a single cluster of 3 adjoining missed points up to and including the central 20 degrees and any additional separate missed points within the central 20 degrees
any central loss that is an extension of a hemianopia or quadrantanopia of size greater than 3 missed points.
What are the peripheral Estermann field requirements for driving?
Regarding peripheral field, the minimum field is “at least 120 degrees on the horizontal, extending to at least 50 degrees left and right of fixation. In addition there should be no significant defect which encroaches within 20 degrees of fixation above or below the horizontal meridian.”
What is the nystagmus like in oculocutaneous albinism?
Nystagmus is pendular, horizontal and increases in bright light. Nystagmus tends to reduce in severity with age.
A patient with Arnold-Chiari malformation has significant, symptomatic down-beat nystagmus. Which medication is MOST likely to benefit?
Clonazepam has been used in the treatment of downbeat nystagmus. By contrast, carbamazepine toxicity has been associated with downbeat nystagmus!
What does PCV look like on ICG?
ICG is the most useful investigation to diagnose polypoidal choroidal vasculopathy. It shows a branching vascular network from the choroidal circulation with polypoidal and aneurysmal dilatations at the terminals of the branching vessels that fill slowly and then leak intensely.
Which medication acts on sympathetic and parasympathetic autonomic ganglia?
Acetylcholine (miochol) acts on all sympathetic and parasympathetic autonomic ganglia. It also acts on parasympathetic peripheral nerve endings. It has a very short half-life but a fast onset, which is useful in producing miosis for 20 minutes during complicated cataract surgery.
What 4 risk factors did the CVOS study find for anterior segment neovascularization?
area of capillary non-perfusion >30 disc diameters
male gender
short duration < 1 month
severe intra-retinal haemorrhage
How to differentiate fundus albipunctatus from retinitis punctata albescens?
because of the normal vasculature (typically attenuated in retinitis punctata albescens, which is a retinitis pigmentosa variant). Familial drusen would appear similar, although the lesions would not be as uniform in size and would form grapelike clusters.
A patient with pigmentary retinopathy had an extra finger removed as a child. All his fingers are stubby. He is obese with type 1 diabetes and renal dysfunction. There is bull’s eye maculopathy.
What is the diagnosis?
Bardet-Beidl syndrome is characterised by:
AR inheritence
pigmentary retinopathy
obesity
brachydactyly or polydactyly
dental anomalies
hypogenitalism
renal disease
cardiac disease
mental handicap
What are the features of VHL?
retinal capillary haemangiomas (which can cause exudative RD)
cerebellar haemangioblastomas
pancreatic, hepatic, and renal cysts
renal cell carcinoma
pheochromocytomas
Which of the causes of neonatal conjunctivitis, if left untreated, may progress to meningitis?
HSV neonatal conjunctivitis may progress to meningitis and is treated with iv acyclovir.
Where are the first, second and third order neurons in the symphathetic pathway?
First order: hypothalamus along the brainstem to synapse in the ciliospinal center of Budge
Second order: centre of Budge to superior cervical ganglion
Third order: superior cervical ganglion, travels along the carotid plexus, branches join the ophthalmic division of the trigeminal nerve and pass through the ciliary ganglion to the nasociliary and short ciliary nerves
Characteristics of cancer-associated retinopathy:
often presents before the diagnosis of primary malignancy
bilateral
cone dysfunction, then rod dysfunction
symptoms, early: reduced acuity and colour desaturation (cones)
symptoms, late: nyctalopia and peripheral field loss (rods)
fundus findings: initially normal
ERG: severely attenuated photopic and scotopic responses and abnormal dark adapation
Prognosis: poor for both vision and life
Causes of angioid streaks include (PEPSI acronym):
Pseudoxanthoma elasticum
Ehlers-Danlos syndrome
Paget’s disease
Sickle cell disease
Idiopathic
Which clinical feature can be used to differentiate classic galactosaemia from galactokinase deficiency?
The key feature clinically differentiating true galactosemia (galactose-1-phosphate uridyltransferase deficiency) from galactokinase deficiency is the presence of hepatosplenomegaly, mental retardation, and other systemic manifestations.
See-saw nystagmus is MOST likely to be associated with:
characteristically a feature of chiasmal lesions.
A 28-year-old man is found to have mid-peripheral yellowish flecks in both eyes. A fluorescein angiogram reveals a silent choroid.
What is the histopathological cause of the fluorescein appearance?
The case description in the question above is characteristic of Stargardt’s disease, where lipofuscin accumulation in the RPE causes blockage of background choroidal fluorescence on the fluorescein angiogram.
Stages of ROP are:
Stage 1: flat demarcation line
Stage 2: demarcation ridge, which protrudes into the vitreous
Stage 3: a ridge with extra retinal fibrovascular proliferation
Stage 4: subtotal RD
Stage 5: total retinal detachment (RD)
The most common inheritance pattern of congenital cataracts is:
The most common identifiable cause of bilateral congenital cataract is genetic mutation (25%), usually autosomal dominant, though it can be autosomal recessive or X-linked.
What are the features of Peter’s anomaly?
Peter’s anomaly is typically sporadic and it is bilateral in two-thirds of cases. It is characterised by absence of posterior corneal tissue and leukoma, ±iris adhesions to leukoma, ±lens-corneal adhesions. Opacification of the cornea leads to an amblyogenic effect on a developing infant. Peters’ plus syndrome includes short disproportionate stature, developmental delay, dysmorphic facial features, cardiac, genito-urinary, and central nervous system malformation. These systemic findings are seen in up to 60% of patients. Peters’ is also associated with many other ocular pathologies including glaucoma, sclerocornea, corectopia, iris hypoplasia, cataract, ICE syndrome, aniridia, iris coloboma, persistent fetal vasculature and microcornea.
Which muscle is innervated bilaterally by a single unpaired nucleus?
The levator muscle is innervated bilaterally by a single, unpaired nucleus.
Which oculomotor muscles are innervated by ipsilateral vs contralateral nuclei?
they are all innervated by ipsilateral nuclei except for the superior rectus and superior oblique, which are innervated by contralateral nuclei.
For a strabismus to be appropriately termed congenital, the disturbance must be documented:
detected in the first 6 months
