Key Points 7 Flashcards
What type of secretions come from Meibomian glands?
Holocrine
What percentage of optic nerve axons cross in the chiasm vs ipsilateral axons?
Approximately 52% of the optic nerve axons cross in the chiasm, whereas 48% remain ipsilateral.
When should tapering steroid doses be considered?
40mg daily in the morning for more than 1 week
repeated evening doses
received more than 3 weeks of treatment
taken a short course but within a year of stopping longterm treatment
What is Sherrington Law
states that when one extraocular muscle is stimulated, the ipsilateral antagonist is inhibited
What is acute retinal pigment epitheliitis
a rare self-limiting inflammatory condition of the macular RPE. It typically affects young adults and is unilateral in 75% of cases.
What conditions are associated with angioid streaks?
Pseudoxanthoma elasticum
Ehler’s Danlos
Paget’s disease
Sickle cell disease
Idiopathic
PEPSI
Efficacy vs Effectiveness?
Efficacy = the effect of something under ideal or laboratory conditions.
Effectiveness = the effect of something in the real world.
What are the features of Pigment Dispersion syndrome?
more common in males and is associated with myopia. The rate of pigment deposition often reduces after the age of 40, perhaps because of the enlarging lens and the changing shape of the iris-lens diaphragm preventing chaffing of the iris pigment against the zonules. Pigment dispersion syndrome responds better to ALT than standard POAG because of the increased pigment in the trabecular meshwork allowing better absorption of laser.
which IOL material is most likely to develop glistenings?
Hydrophobic acrylic IOLs have been associated with glistenings in the optic. These glistenings are water (from the aqueous) that becomes trapped as droplets in a hydrophobic environment.
What are features of congenital (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
Risk factors for developing ROP?
hyperoxia, low gestational age, and low birth weight
Which conditions show Intermediate uveitis?
sarcoidosis, multiple sclerosis (MS), Lyme disease, tuberculosis (TB), and syphilis. Idiopathic intermediate uveitis, or pars planitis, accounts for >80% of cases. Eighty percent of pars planitis cases are bilateral.
What is the commonest cause for reduced vision in pars planitis?
Macular oedema, followed by cataract, is the most consistent cause of decreased vision in pars planitis. Cystoid macular oedema (CMO) may complicate anterior or posterior uveitis, but much less frequently.
What is phacoanaphylactic anaphylaxis?
occurs as a result of an immune response to lens proteins released following the rupture of the lens capsule which may occur following trauma or incomplete cataract extraction.
What are the features of superior division CN3 palsy?
superior rectus and levator palpebrae affected
Which study from the 1980s recommended grid pattern macular photocoagulation for persistent macular oedema if visual acuity was 20/40 or less and in the absence of non-perfusion:
BVOS
In Possner-Schlossman syndrome raised IOP is believed to be the result of:
involves an acutely raised IOP secondary to trabeculitiis with open angles. It is believed to be precipitated in many cases by Herpes simpex virus.
A patient has a homonymous visual field defect respecting the midline and complains of experiencing formed visual hallucinations.
These features are MOST in keeping with a lesion of the:
A temporal lobe lesion causes an incongruous, contralateral upper homonymous quadrantanopia. It may also give rise to formed visual hallucinations. This is in contrast to the occipital lobe, where visual hallucinations are unformed.
A 45-year-old man presents with rapid onset non-axial proptosis and pain. Incisional biopsy of the mass shows a ‘Swiss cheese’ appearance.
What is the most likely diagnosis?
Adenoid cystic carcinoma can present with pain due to perineural spread. It has a classic ‘swiss-cheese’ appearance on histology.
What proportion of congenital NLD is bilateral?
Less than 10%
What is the most likely outcome following inadvertent suturing of the orbital septum into subcutaneous tissues when repairing a partial-thickness upper eyelid laceration?
upper lid retraction in downgaze.
At what wavelength does he Nd:YAG emits infrared radiation
1064nm
Which conditions are ALT likely to be effective?
ALT is successful in:
primary open angle glaucoma
pigmentary glaucoma
pseudoexfoliation glaucoma
normal tension glaucoma
Which conditions are ALT not likely to be effective?
paediatric glaucomas
secondary glaucomas
