Key points Flashcards
Phakic eye with silicone oil induces what refractive error?
hyperopic shift usually between 5-9 dioptres
Aphakic eye with silicone oil induces what refractive error?
myopic shift
What is the prevalence of contralateral FTMH in patients with established MH
The prevalence of bilaterality of idiopathic macular holes, including earlier stages before a full-thickness dehiscence develops, will be higher, approaching 20% to 25%. Because a large proportion of early holes spontaneously resolve, only a small fraction (5%) develop bilateral full-thickness defects.
What type of lenses does the panfundoscope lens consist of?
2 convex lenses
When doing IO, is the 20D lens held further or closer to the patient than the 30D lens?
Further away
Which drug is SJS associated with mainly?
Sulphonamides
Diagnosis? A patient with a history of recurrent haematuria has increasing myopia, anterior lenticonus and macular flecks.?
Alport syndrome
Histopathological findings in Alport syndrome?
a defect in Type 4 (basement membrane) collagen
Features of Alport syndrome?
1) glomerular basement membrane nephritis
2) anterior lenticonus
3) cortical cataract
4) posterior polymorphous dystrophy
5) dot-fleck retinopathy
Inheritance pattern of Alport syndrome?
X-linked recessive (80%) and X-linked dominant (5%) forms
Congenital Causes of Ectopia Lentis
Familial
Aniridia
Marfan’s
Homocystinuria
Weill-Marchesani
Hyperlysinaemia
Sulphite oxidase deficiency
Stickler’s syndrome
Ehlers-Danlos syndrome
Acquired causes of Ectopia Lentis
Trauma
Large eye (myopia, buphthalmos)
Anterior uveal tumours
Hypermature cataract
In severe TB, what proportion of patients is the Mantoux test negative in?
50%
POAG risk factors?
elevated IOP
positive family history of glaucoma
myopia
diabetes mellitus
cardiovascular disease
African American race
asymmetric cupping
large cups
early nonspecific visual field changes
thin corneas
What is the surface tension of silicone oil like in comparison to all the gases?
Significantly less than all gases
Features of lateral medullary syndrome?
ipsilateral vestibular nuclei symptoms (vertigo, nausea, nystagmus)
ipsilateral cerebellar signs such as dysdiadokinesia and dysmetria
lateral spinothalamic tract damage causing contralateral pain and temperature sensation loss
spinal trigeminal nucleus damage causing ipsilateral facial paraesthesia
ipsilateral Horner’s
ipsilateral bulbar signs such as hoarseness and dysphagia
Features of Terrien’s marginal degeneration
an uncommon, idiopathic, non-inflammatory condition
male preponderance
typically bilateral
peripheral corneal thinning
occurs superiorly first, then circumferentially
intact epithelium in an essentially quiet eye (unlike Mooren’s ulcer or PUK)
peripheral gutter: outer slope shelves gradually, central slope rises sharply
separated from limbus by clear zone
perforation is rare
against-the-rule astigmatism is often induced (flattening in the vertical meridian)
pseudo-pterygia can develop in longstanding cases
Treatment: rigid gas-permeable contact lens; crescentic patch graft in severe cases
Features of Parinaud’s dorsal midbrain syndrome?
light-near dissociation
mydriasis
Collier’s sign (lid retraction in primary position)
paralysis of convergence and accommodation
paralysis of upgaze (supranuclear palsy)
convergence-retraction nystagmus (worsened by upward rotation of OKN drum)
skew deviation
papilloedema or optic atrophy (if ventricular flow compromised)
Commonest cause of Parinaud’s Dorsal Midbrain Syndrome?
infants: hydrocephalus
young children: pinealoma
young adults: head trauma and multiple sclerosis
older adults (60 years): stroke
What is ICE syndrome?
caused by an abnormal corneal endothelial cell layer which proliferates and migrates across the angle and onto the iris
Commonest complication of ICE syndrome?
Glaucoma occurs in about 50% of cases, due to synechial angle closure secondary to contraction of this abnormal tissue.
What is thought to cause ICE syndrome?
PCR suggests a possible herpes simplex viral origin to the disease process.
Focal lymphoid aggregates in the substantia propria of the conjunctiva are otherwise known as:
Conjunctival follicles represent focal lymphoid aggregates in the substantia propria.
Follicles vs papillae?
The central part of the follicle is avascular, but dilated blood vessels may surround the base and sweep up from the base over the convexity
Papillae are vascular changes most prominent on the palpebral conjunctiva and the limbus; sites where fibrous septa anchor the conjunctiva to the underlying tissues. In contrast to follicles, papillae have a dilated vascular core surrounded by oedema and a mixed inflammatory infiltrate producing raised elevations of the conjunctival epithelium.