What is duochrome test ?
Defination of duochrome test is Duochrome test is subjective refraction procedure of eye.
In which procedure patient saying and according with patient we record result so this procedure called as subjective refraction. This procedure contain red and green color on Snellen chart.
Why red and green color in duochrome ?
As we know that duochrome test contain red and green color but you thing about that, why only red and green and why not other.
What is power in that colour or what is logic about that so we learn about there logic of color.
Each and every color make with different frequency as same red colour have high frequency and green colour has low frequency. If high color frequency it focused behind the retina and low frequency in front of retina so we used this both color for duochrome test.
Principle of duochrome test ?
Duochrome test is basically based on the chromatic abrasion, as rule of chromatic abrasion red color is high frequency and focused behind the retina and green color have low frequency and focused in front of retina.
What is chromatic abrasion ?
Why duochrome test done ?
Duochrome test is most commonly used in subjective refraction procedure. It is used for to see the given spherical correction is under correct and over correct the refractive error.
In basic word it used for the given refraction is correct or not.
How do the duochrome test ?
As duochrome test is subjective refraction of eye. It is dark room or semi dark room procedure. In which procedure contain red and green color.
As color line is on the Snellen chart and chart placed at 6 meter distance away from the patient.
Optometrist or ophthalmologist need to require ask to patient read both color line and tell which one is more clearer, sharper and visible than other.
As patient saying we have to note their result
If patient saying red one clearer then optometrist need to add plus glasses and if green clearer then add minus glasses.
How note duochrome test result ?
If patient seeing both color and saying one of the color is more better than other when they have chances to myopic and hypermetropia.
If patient says red is more better than green such patient having Hypermetropia and need to plus glasses (convex lens ) to treat the Hypermetropia.
If patient says green is more better than red such patient having myopic and need minus glasses (concave lens ) to treat the myopia.
If patient says both color are equally sharp, clear and bold such patient is emmetropic.