Saturday, December 3, 2011

How can Vision be tested? how can color fantasy be tested?

How can Vision be tested? how can color fantasy be tested?
testing trance is called optical acuity & it is done through Landolt's chart (contains symbols of different sizes & u tell the crack while u sit on a chair 6 metres away), better immediately by computer; may also b done through neutralizing the red reflex by lenses of different powers till u find the result.
colour vision is tested by Ishihara question paper; which is a card containing coloured circles; if u colour blind u will mis-read the number formed by combination of circles through contrast colour background
Vision is tested subjectively by using charts have letters or signs of different sizes . Objectively figment of the imagination is tested by refraction using plane or concave mirror, more acurately with a computer assuming mansion of lens is taken into cosideration.
Color vision is tested by 1)Homegren`s wools 2) Ishihara`s pseudo iso chromatic charts 3)Edridge Green`s color perception lantern and 4) Nagl`s Enameloscope.

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