The document discusses reflection of light and its uses in ophthalmology. Reflection occurs when light rays traveling in one medium hit the boundary of another medium and turn back into the first medium. There are two main types of reflection - specular reflection which occurs from smooth surfaces and causes light to reflect at the same angle, and diffuse reflection which occurs from rough surfaces and scatters light in all directions. In ophthalmology, the cornea's anterior surface acts as a convex mirror and reflection is used by instruments like the keratometer.

1. Hammad Tariq
Optometrist
Isra Medical University Islamabad

2. Reflection
Conditionsforreflection
Lawsofreflection
Typesofreflection
OphthalmicUse

3. Luminousobjectsarethosewhichgiveofthere
ownlighte.g.sun
Non-Luminousobjectsarethosewhichdon’t
giveoftheownlighte:gmoon

4.  Reflectionisthechangeindirectionofawave
front betweentwodifferentmediasothatthe
wavefrontreturnsintothemediumfromwhich
itoriginated
 Whenlightraystravelinginamedium
reachestheboundaryofothermedium,theyturn
backtothefirstmedium.Thisphenomenonof
turningbackoflightintothesamemediumafter
strikingtheboundaryofothermediumiscalled
ReflectionofLight

6. Thereshouldbesomeincidentray
Thesurfaceshouldbepolished

7. TheINCIDENTray,REFLECTEDray
andtheNORMALallliesinthesamePLANE

8. AngleofINCIDENTisalwaysEQUALto
angleofREFLECTION

9. REFLECTEDrayisalwaysOPPOSITEto
INCIDENTray

10. Reflectioniscategorizedintowhichisasfollows
SpecularReflection
DiffuseReflection

11. Ifthereflectingsurfaceissmooththe
REFLECTIONthoughtitwillbecalled
SPECULAR reflection

14. Whenlightstrikessurfaceofnon-metallic
materialitbouncesoffinall directionsbythe
microscopicirregularitiesthisiscalleddiffuse
reflection
Or
Ifthereflectingsurfaceisroughthereflection
thoughtitwillbecalleddiffuserefection

16. Theanteriorsurfaceofcorneaactsasaconvex
mirror.
Itisusedsuchbythestandardinstruments
(Keratometer)