Fundamentals of ophthalmology Flashcards
What questions would you ask if a patient presents with visual disturbance?
one or both eyes?
when did it start?
gradual or sudden?
where in vision?
double vision?
associated symptoms?
distortion?
What questions would you ask if a patient presents with red eye?
one or both eyes?
discharge?
pain?
lacrimation?
blurred vision?
photophobia?
associated symptoms?
What questions would you ask if a patient presents with eye pain?
SOCRATES
How is visual acuity measured?
Snellen chart, 6m
numerator = distance 6m chart is read from
denominator = distance a person with normal eyesight could read the line from
Describe the pinhole effect
pinholes eliminate all but straight beams of light which fall directly on the retina, giving a clear image
How is colour vision assessed?
Ishihara colour charts
What is hypermetropia?
long-sighted eye
image is focussed behind the retina
often a smaller eye than average
How is hypermetropia corrected?
convex lens, converges the light to hit the retina
What is myopia?
short-sighted eye
image focussed in front of retina
often a larger eye than average
How is myopia corrected?
concave lens, diverges the light to hit the retina
What does it mean if vision improves with pinhole?
refractive error and therefore needs glasses
if it doesn’t improve then the problem is not refractive, the problem is somewhere else in the eye
Which cranial nerves allow oculomotility?
CN 3,4 + 6
eye will deviate if any of these are affected
What happens if you shine a light in one pupil?
both pupils constrict
What happens when you shine light on one eye, and there is a tumour on an optic nerve?
both pupils constrict
What happens if you swing a light between pupils when there is a tumour on an optic nerve?
both pupils dilate
swinging flashlight makes brain think light has decreased, therefore pupil dilates
called relative afferent pupillary defect
What is anisocoria?
difference in pupil size
In dim light, would a larger or smaller pupil be abnormal?
smaller pupil
In bright light, would a larger or smaller pupil be abnormal?
larger pupil
Horner’s syndrome signs
(PAMELa)
Ptosis
Anhydrosis
Miosis
Enophthalmos
Loss of ciliospinal reflex
What happens in Horner’s syndrome if 4% cocaine is added?
normal pupil dilates
Horner’s pupil does not dilate (loss of sympathetic tone)
cocaine does not have an effect on Horner’s
What happens in Horner’s syndrome if 1% hydroxyamphetamine is added?
pre-ganglionic = both pupils dilate
post-ganglionic lesion = Horner’s pupil does not dilate
What happens in Horner’s syndrome when 1:1000 adrenaline is added?
pre-ganglionic lesion = both pupils do not dilate
post-ganglionic lesion = Horner’s pupil will dilate
What happens in Horner’s syndrome when Apraclonidine (0.5% or 1% is added)?
no effect on normal pupil
(upregulatin of alpha-1 receptors - denervation hypersensitivity)
Horner’s pupil dilates
What should you comment about the optic nerve on fundoscopy?
colour
contour
cup-to-disc ratio
