4 • Defects of / Helping The Eye

Label This Image

The Eye

a - cornea

b - lens

c - retina

d - optic nerve

e - ciliary muscle

f - iris

Define The Power of Accommodation of the Eye

The human eye can form images of objects at distances from it in immediate succesion

Define Near Point of The Eye

The nearest point at which an object can be seen clearly by the eye

How far is that Near-Point of the eye

25cm from the normal eye

Define Far Point of the Eye

The furthest point at which an object can be seen clearly by the eye

Define Range of Vision

Objects located between the near and far point can have an image formed on the retina by the eye

Label This Image

The Range of Vision

a - Far point

b - Near Point

c - Range

d - 25cm

Name the defect of this eye

Near / Short sighted

Define Near Sighted / Short Sighted

Far is point is too near - distant objects cannot be seen clearly

Describe the image within a Near Sighted Eye

Eyeball is too long so the image if a distant object forms in front of the retina

How can Near Sighted-ness be Corrected?

Diverging Lens

Name the defect of this eye

Far / Long sighted

Define Far Sighted / Long Sighted

Near point is too far - close objects cannot be seen clearly

Describe the image within a Far Sighted Eye

Eyeball is too short causing the image t be formed behind the retina

How can Far Sighted-ness be Corrected?

Converging Lens

Name 2 Optical Instruments

Microscope

Telescope

Define the function of a Microscope

Viewing very small objects

Define the final image of a microscope

Final image formed at near point

Name the types of microscopes

1. Magnifying glass

2. Compound Microscope

Define the function of a Telescope

Viewing distant objects

Define the final image of a telescope

Final image formed at far point

Name the types of telescopes

Astronomical

Terrestrial