L10- Optics Of CL

Question 1

Vertex distance equation

Answer 1

F’cl = (F’spec) / (1-dF’spec)

Question 2

Correcting myopia

Answer 2

CLs have longer distance over which to bring light to focus than specs (fc lens > fspec lens). So, BVP of CL must be lower than equivalent spectacle to correct myopia.

Question 3

Correct hyperopia

Answer 3

CLs have a shorter distance over which to bring light to focus than specs (fclens < fspec lens). So, BVP of a CL must be greater than the equivalent spectacle to correct hyperopia.

Question 4

Spectacle magnification (SM) =

Answer 4

Corrected ametropic image size / uncorrected ametropic image size

Question 5

Contact lens magnification (CLM) =

Answer 5

Corrected image size with CLs / corrected image size with specs

Question 6

Relative spectacle magnification (RSM)

Answer 6

The ratio of the image size in the corrected ametropic eye to the image size in the normal emmetropic eye.

Question 7

Field of view specs vs CL

Answer 7

Field of view greeting in CL than specs

Question 8

Convergence (hyperopes and myopes in CLs)

Answer 8

CL wearing hyperopes converge less

CL wearing myopes converge more

Question 9

Accommodation (hyperopes and myopes in CLs)

Answer 9

CL wearing hyperope accommodate less

CL wearing myope accommodate more