exam questions Flashcards
The blocks are set at 90°and 180 °on the fan and block chart, and the patient has a refractive error of -1.50DC x 180, describe the appearance of the fan and the blocks on the chart.
The patient will report the Maddox V needs to be moved to an orientation of 90° (180 ° on the chart because it is corrected). Both sides of the arrow equally clear. Vertical block clearer (parallel to arrow)
Where does the circle of least confusion needs to be in order to perform JCC?
on the retina
What spherocylindrical lens do you need to result in a +/- 1.00DC JCC?
Answer: +1.00/-2.00DC
jcc lens can be either 0.25,0.5,0.75,1
jcc is a sphere lens with a cyl with twice the power of the sphere and sign flipped
so to get 1dc jcc you would need a +1ds sphere and a -2dc
so baso the cyl is twice the sphere.
so a 0.5jcc would be +0.5/-1.00DC
A 15 year old patient attends for his first eye examination. He
complains that his vision is blurred in both eyes and the blur is more
noticeable for distance vision than near. The best vision sphere is
-1.00DS and VA is 6/9, estimate the patient’s refractive error
estimated cyl is -1.00 with 6/9 so you need to add 1/2 cyl in positive sphere to the best sphere in order to get the spherical component so we use the best vision sphere bit to work out the sphere. make sure you add half the cyl to it though
so the cylinder is -1.00 which we get from the table. then half of that is 0.50 which we add onto -1.00 (bc you add half cyl in positive sphere) so it becomes -0.50
so estimated prescription/ refractive error is
-0.50/-1.00 x ?
ou find the RX of a patient is -2.00DS and VA 6/5. You use +1.00DS
check test and VA is 6/7.5. How do you explain this result?
a. The focal point of this patient with -2.00DS is in front of the retina
b. The focal point of this patient with -2.00DS is behind the retina
c. This patient cannot accommodate
d. This patient has lazy eye
behind the retina
because its getting worse which means it was correct first and now your giving plus so it shifts behind the retina (relatively more hyperopic)
What sphere check test would you use in a 65 year old with cataract?
a. +1.00DS
b. Duochrome
c. Plus/minus lenses
d. None
plus or minus lenses
List 2 procedures you would use to ensure your patient is not accommodating when are
performing retinoscopy.List 2 procedures you would use to ensure your patient is not accommodating when are
performing retinoscopy.
*List 2 procedures you would use to ensure your patient is not accommodating when are
performing subjective refraction
Keep both eyes open
*Use duochrome (distance) or sport of light
*Don’t block patient’s view
*Fogging when doing retinoscopy
- Give the most positive lens (or minimum minus) that provides maximum visual acuity
*If you are testing a hyperope with accommodation, do not remove the trial frame lens until the
new one is in place
*+1.00 check test
2 In what type of patients you would use the entoptic phenomenon called
Haidinger’s brushes? (2 marks)
When you suspect the patient might have a problem in the macula (1 mark)
Such as macula oedema, AMD, macular hole (1 mark)
