7.1.1: Refract range of pxs with optometric problems using objective & subjective measures

Question 1

What important checking tests are there during refraction?

Answer 1

• Use +1.00 Blur/duo
• Use Pinhole

Question 2

What are tips for accurate cylinder power?

Answer 2

• BVS
• Make sure px is just clearer on green duochrome to ensure circle of least confusion is on the retina
• For every -0.50 increase in cyl, add +0.25 sph.

Question 3

What does each acuity roughly relate to in dioptres?

Answer 3

6/6 - 0
6/9 - -0.50
6/12 - -0.75
6/15 - -1.00
6/20 - -1.25
6/30 - -1.50
6/45 - -2.00
6/60 - -2.50
6/75 - -3.00

Question 4

What is the age expected prebyopic corrections?

Answer 4

40yo - +1.00
43yo - +1.25
45yo - +1.50
48yo - +1.75
50yo - +2.00
55yo - +2.25
60yo - +2.50