Key points 24 Flashcards
What is the eye popping reflex?
a normal neonatal reflex which involves a pronounced widening of the palpebral fissures after an abrupt decrease in ambient illumination primarily, or after loud noises. It is present within the first 3 weeks of life in 75% of infants born.
Conjunctival papillae are a normal appearance in young people especially at which location:
Most healthy young people have small conjunctival papillae along the superior margin of the upper tarsus, which is easily visible on lid eversion.
Characteristics of Mooren’s ulcer?
Mooren’s ulcer causes severe pain, can be unilateral or bilateral, typically starts in the interpalpebral region, is associated with epithelial defects, has an overhanging inner edge of the ulcer and there is a high risk of perforation. Cataract may also be present.
Characteristics of Terrien’s degeneration?
Terrien’s ulcer causes less pain with less intense inflammation, it begins in the superior and inferior cornea, the epithelium is intact, the edge is sloping (not overhanging) and there is a low risk of perforation.
What conditions is downbeat nystagmus associated with?
Drugs (lithium, phenytoin, barbituates)
Wernicke’s encephalopathy
Paraneoplastic cerebellar degeneration (e.g. small cell lung)
Craniocervical junction lesions (tumour, syrinx, Arnold-Chiari)
A 7-year-old boy presents with difficulty reading at school. On examination, visual acuities are 6/18 bilaterally and radial straie are noted at the fovea bilaterally, especially under red-free light. A fluorescein angiogram does not reveal any leakage. In the periphery, you note vitreous veils.
Where is the most likely pathological defect?
The case presentation is most in keeping with congenital X-linked retinoschisis. The splitting occurs in the retinal nerve fibre layer, as opposed to acquired (senile) retinoschisis where the splitting occurs in the outer plexiform layer.
When used with prisms, which of the following tests is most appropriate for quantification of a tropia only, with no contribution from a phoria?
In the simultaneous prism-cover test, as the fixing eye is covered, a prism is simultaneously placed over the deviated eye. When there is no re-fixation shift, the prism has neutralized the tropia. The alternate-cover test with prisms will neutralize total phoria plus tropia. The cover-uncover test with prisms will neutralize tropia plus part of the phoria.
What sign most reliably differentiates iridocyclitits from iritis:
Cells in the anterior vitreous - in an otherwise anterior segment uveitic picture - indicates irido-cyclitis (involvement of the ciliary body). Snow-banking and snow-balling are signs of pars planitits, while flare is evident in any anterior uveitic presentation due to leakage of proteins across the blood-aqueous barrier.
Common, identifiable causes of bilateral congenital cataracts:
autosomal dominant inheritence
metabolic or systemic disease: e.g. DM, galactosaemia, or Lowe’s syndrome
Common, identifiable causes of unilateral congenital cataracts:
local dysgenesis (sporadic)
PHPV
lenticonus
What do Lattice degeneration and meridional complexes increase the risk of?
RRD
