Unit 1 Ocular Anatomy

Christiaan Huygens

Wave Theory Of light

Sir Isaac Newton

light was made up of tiny particles

James Clerk Maxwell

Light is an electro magnetic wave

Leon Foucault

Speed of light

Max Planck

Quantum Theory

Albert Einstein

Photo electric effect

Frequency formula

Speed/wavelength

Long wavelength

Low Frequency

Short wavelength

High frequency

Foot Candle (historical)

light from a single candle falling on a surface 1 foot away; Amount of light that reaches a surface area.

Foot Candle (current)

a unit of illumination equal to one lumen per square foot

Luminous Flux

quantity of energy of light emitted per second in all directions.

Lux

is the unit of illuminance and it is an indication of how much light is incident on a surface

Concave

diverging

Convex

converging

Index of refraction formula

speed of light in air/speed of light in substance

Snells law formula

n1 sin ɵ1 = n2 sin ɵ2

Light entering a prism

towards the base

Prism Formula

C/D

Convex Lens

Base to Base

Concave lens

Apex to Apex

Concave or Convex

Concave

Concave or Convex

Convex

Focal Length Formula

1/f

Convex Lens properties

Plus power, Magnified, Behind the Lens, Real & inverted.

Concave Lens Properties

Minus power, Minified, Infront of lens, Virtual and Upright.

(+3.00)-2.00 ×180

Spherical Power

+3.00(-2.00)x180

Cylinder Power

+3.00-2.00(x180)

Axis

Emmetropia

Images from distance objects are formed at the central retina

Ametropia

Images from distance objects are focused either in front of or behind the retina, in one or both the meridian. Refractive error present.

Myopia

Light rays focus in front of the retina & corrected with diverging or minus lenses. Eye is longer.

Hyperopia

The eye is shorter so the focal point for parallel light rays lands behind the retina. Corrected with plus or converging lenses.

Astigmatism

When parallel rays of light do not come to a single point focus on the retina. Corrected with coronoid of strum

Anisometropia

A condition in which the two eye have unequal refractive errors

Aniseikonia

A difference in image size and/or shape seen by both eyes

Accomodation

Eye changes its power to focus on near objects

Amplitude of accommodation

measures the closest point that the eye can focus

Presbyopia

Loss of accommodation associated with aging

Latent hyperopia

Amount of hyperopia that can be overcome with accommodation