weird questions Flashcards
describe what you assess when examining the eye
- Assess the disc appearance (1mark)
o Colour of the disc- (1mark)
o Assess Cup to disc ratio (1 mark) and compare with the other eye (1 mark)
o If Rim ISNT rule applies (1 mark)
o Disc margin- Clear and Well defined (1 mark). - Fundus appearance- Red-orange colour retina. There are no lesions, scars, or
pigmentary changes. (1 mark) - Assess macula (1 mark)
- Assess Fovea (1 mark)
- Assess arteries and veins (1 mark)
- Work along major vessel in the 4 quadrants (1 mark)
- Mr Patel, a 45 year-old bus driver, has not had an eye exam in 3 years. He reports his
mother has glaucoma. His intraocular pressure is 30mmHg in both eyes and the colour of his
irises is blue-green. You want to assess the optic disc of this patient but you decide not to
use the direct ophthalmoscope. What technique would you use to examine the patient’s
fundi? Describe the power of the lens you would use. Explain your rationale (5 marks)
Indirect biomicroscopy ( 1 mark) because it provides greater magnification than headset BIO
(1 mark) so better to assess the optic disc in detail ( 1mark)
Power of the lens +60D or +66D ( 1 mark). It has good mag so better to assess the optic
disc (1 mark)
What are the three basic elements that determine the eye’s ability to focus light?
Shape of cornea
Power of crystalline lens
The axial length of the eyeball
Miss Logan comes to you practice reporting poor visual acuity at distance. Her unaided
vision is 6/18 in each eye and you want to use a pinhole. Explain the principle behind this
test and the possible outcomes.
It reduces the effective pupil size reducing the diameter of the
retinal blur circle. Pinhole is placed in front of each eye. If VA improves, refine
subjectively if not then possibly pathology or amblyopia.
A retinoscope is described as having:
a) a 1D convergent beam
b) a 1D divergent beam
c) a plane mirror
Where is the apparent light source (i.e. where does the light appear to come from) in
each of these retinoscopes?
6.a) 1m in front of mirror, b)
1m behind mirror, c) infinity
Preferential looking is a method of
assessing vision in:
infants
Which of the following factors
could result in hyperopia?
1. Cornea too curved
2. Lens too weak
3. Eye too long
4. Cornea too thin
5. Lens too strong
lens too weak
If you are performing ophthalmoscopy on a
high myope, which adjustment to the normal
routine might make the examination easier?
Ask the patient to wear their glasses
.State where the far point for an emmetropic eye is: (1 mark)
2.State where the far point for a hyperopic eye is: (1 mark) and a myope
far point for an emmetrope is at infinity
far point for a hyperope- behind eye
far point for a myope- front of eye
Describe the possible errors you can make in measuring monocular distance visual acuity.
(2 marks)
If the patient leans forward – this will decrease the distance between the patient and the
visual acuity chart and so results will be inaccurate
* If the patient has both eyes open and you want to measure monocular visual acuity – this is a
monocular assessment so if the patient has both eyes open the results will not be accurate.
* If the patient squints their eyes – this will give the same effect as if a pinhole aperture was
placed in front of the eye which would improve the patient’s acuity (unless the patient has
amblyopia or an ocular pathology). This would give inaccurate results.
) In which patients might the duochrome test not work and why? (2 marks)
Duochrome may not work in those patients with visual acuity worse than 6/12, as the ring targets
are usually constructed of ring thicknesses equivalent to 6/9 (inner) and 6/12 (outer) Snellen
equivalent targets.
It will not work if prescription is significant incorrect because the The difference in focal position due
to chromatic aberration is 0.50DS.
Small pupil will reduce size of blur circles because the difference between the clarity of red and green
is reduced
why does duochrome work better with larger pupiols
bc the test relies on the chromatic aberration of the eye which is a tendency of the eye to focus different colours at different distances.
pupil is larger= blur circle is larger so makes it easier to accurately determine rx.
describe what happens to an image w diff types of ametropia
Myopia – image is magnified (m more than 15x)
* Hyperopia – image is minified (m less than15x)
* Astigmatism – different magnification in each meridian and it also depends on type of
astigmatism (hyperopic, myopic or mixed)
* Emmetropia- image magnification 15x
To examine the ret movement at an axis of 90, in which direction should the ret be
moved?
2. To examine the refractive error at axis 45, in what direction should the ret be
moved?
. To examine the axis of 90, turn the streak to horizontal direction
(180) and tilt the retinoscope up and down (along the vertical
meridian)
2. To examine the axis of 45, turn the streak to 135 and tilt the
retinoscope up and down (along 45)
A patient has a Rx of -1.25DS/-0.50DC x 180. You observe this patient using a ret
with no lenses in place from a distance of 2/3m. What movements are seen?
Along 180, -1.25DS, FP is at 80cm behind the examiner so with
movement at 180
Along 90 -1.75DS, FP 57cm so between patient and examiner so this is an against movement.
