When performing streak retinoscopy on a child wearing +3.00D lenses and dilated with cyclopentolate. What would be the refractive error if neutrality occurs when the retinoscope mirror was located at the following distances:

a. 25 cm

b. 33cm and 

c. 50cm?

 

Answer 
a. -1.00D
b. emmetropia and
c. +1.00D
The working distances and their dioptre equivalents are as follow:
66cm = 1.50D
50cm = 2.00D
33cm = 3.00D
25cm = 4.00D