ABO Advanced Formulas Questions Solved 100% Correct

ABO Advanced Formulas Questions Solved 100%
Correct
Resolving Prism=

Vertical = (prism)(sin angle)
Horizontal = (prism) (cos angle)

Resultant Prism=

The square root of (Vertical prism^2) + (Horizontal prism^2)
tan a=V/H

Shape Factor=

1/1-(T/NxF)
T=center thickness in m
N= index of refraction of lens material
F= front base curve

Power Factor=

1/1-(HxD)
H= vertex distance plus 3 mm in m
D= Dioptric power

Spectacle Magnification=

shape factor x power factor
1/ 1-(T/NxF) x 1/1-(HxD)

Power in Oblique Meridians=

Total power = sphere power + cyl power x sin^2 (O)

Snell's Law=

, N1 sin i = N2 sin r
N1= index of refraction of incident medium
i= angle of incidence
N2= index of refraction of refracting medium
r= angle of refraction

Angle of reflection=

angle I= angle r
I= angle of incidence
r= angle of reflection

Angle of incidence=

I=r+d
I= angle of incidence
r= angle of refraction
d= deviation

Index of refraction=

Speed of light in a vacuum/Speed of light in the medium

Prentice Rule=

Prism= (hxd)/10
h=distance moved in mm
D= total dioptric power for the meridian

Thick Lens Back Vertex Power=

De= D1+D2+ (t/n x D1^2)
De= effective, vertex or lensometer power
D1= true power of the front curve
D2= ture power of the back curve