Optical Formulas

Index of Refraction - CR39

N = 1.498

Index of Refraction - Polycarbonate

N = 1.586

Index of Refraction - Trivex

N = 1.53

Index of Refraction - Hi Index Plastic

N = 1.60

Index of Refraction - Crown Glass

N = 1.523

What is the speed of visible light in air?

186,000 m/s

2nd law of Refraction

LMN* less dense > more dense > toward normal

3rd law of Refraction

MLA^ more dense > less dense > away from normal

Wavelength - Red

660

Wavelength - Orange

610

Wavelength - Yellow

560

Wavelength - Green

510

Wavelength - Blue

460

Violet

400

What is Refraction?

The bending of light when it passes from one transparent material to another of a different optical density

Plus lenses

con VEX - Converge vergence / Increase Vergence

Minus Lenses

con CAVE - diverge vergence / decrease vergence

Formula to find focal length

Distance equals 1 divided by focal length

Formula to find the speed of light when refracted through a material

the speed of light in a material equals the speed of light in air (186,000) over the index (N)

SOLM = SOLA/N(index)

Dispersion

the breaking down of white light into its component colors

Abbé Value

Measurement of the ability of a material to disperse white light into its component colors

Higher the Abbé

:) ^ Abbé = v Dispersion

Lower the Abbé

:( v Abbé = ^ Dispersion

Emmetropic

without accommodation brings parallel light to a point focus

***no correction needed 20/20 vision

Ametropic

without accommodation DOES NOT bring light to a point focus ***correction needed

Myopia

Point focus in front of the retina

Hyperopia

Point focus behind the retina

Simple Hyperopic Astigmatism

pl, +

Simple Myopic Astigmatism

pl, -

Compound Hyperopic Astigmatism

+,+

Compound Myopic astigmatism

-,-

Mixed Astigmatism

+,-

Formula for Spherical Equivalent

SE = (cyl/½)-sph

Myopia

point focus in front of retina

Hyperopia

point focus behind the retina