week 5

Question 1

how does a pinhole affect vision

Answer 1

reduces pupil size and decreases blur circle on retina for ametropes

emmetropes = reduces light level increasing diffraction

Question 2

basic blurred image height definition

Answer 2

height of chief ray at retina

chief ray = ray passing through centre of entrance pupil

Question 3

how is the retinal image affected bybspectacle magnification in myopes vs hypermetropes

Answer 3

smaller retinal image = spectacle corrected myopes
K = -ve
minifcation

larger retinal image for spectacle corrected hypermetropes
K = +ve
magnification

no effect on contact wearers SM =1