Hammad TariqOptometrist
Isra Medical University Islamabad
Reflection
Conditions for reflection
Laws of reflection
Types of reflection
Ophthalmic Use
Luminous objects are those which give of there own light e.g. sun
Non-Luminous objects are those which don’t give of the own light e:g moon
Reflection is the change in direction of a wave front between two different media so that the
wave front returns into the medium from which it originated
When light rays traveling in a medium reaches the boundary of other medium, they turn
back to the first medium. This phenomenon of turning back of light into the same medium after striking the boundary of other medium is called
Reflection of Light
There should be some incident ray The surface should be polished
The INCIDENT ray, REFLECTED ray and the NORMAL all lies in the same PLANE
Angle of INCIDENT is always EQUAL to angle of REFLECTION
REFLECTED ray is always OPPOSITE to INCIDENT ray
Reflection is categorized into which is as follows Specular ReflectionDiffuse Reflection
If the reflecting surface is smooth the REFLECTION thought it will be called
SPECULAR reflection
When light strikes surface of non-metallic material it bounces off in all directions by the microscopic irregularities this is called diffuse
reflection Or
If the reflecting surface is rough the reflection thought it will be called diffuse refection
The anterior surface of cornea acts as a convex mirror.
It is used such by the standard instruments (Keratometer)