DETERMINATION OF REFRACTIVE ERROR IN HUMAN EYE.pptx

I'm an Optometrist and I want to share my knowledge about how to measure visual acuity in human eye

1. DETERMINATION OF REFRACTIVE ERROR Bimal kumar thakur Consultant optometrist

2. Types of Refraction Subjective Refraction: To determined by subjective means the combination of spherical and cylindrical lenses necessary to provide best visual acuity.(with accommodation is at rest) Objective refraction: When the refractive error of an eye is determined without input by patient, To obtain an objective measurement of the patients refractive state.

3. Technique of subjective refraction Jcc Fogging method Duochrome test Wfdt Stenopic slit Ast:fan Sun burst dial/clock dial Red green filter Maddox rod Binocular balancing Binocular best vision sphere

4. Objective refraction Retinoscopy Auto refractometer

5. retinoscopy

6. Conti…… An accurate objective measurement of the refractive state of an eye can be made using the retinoscope The technique is called retinoscopy Pupilloscopy, shadowscopy , skiascopy , umbrascopy , scotoscopy