Thank you for simplying interpretation of retinoscope findings.. Can you also explain how to determine whether the astigmatism is with the rule or against the rule?
In with the rule astigmatism, you will have concave cylinder between 150 to 180 axis and between 0 to 30 axis, or a convex cylinder between 60 to 120 axis
In against the rule astigmatism, you will have convex cylinder between 150 to 180 axis and between 0 to 30 axis, or a concave cylinder between 60 to 120 axis
Thats depends on what distance you are performing retinoscopy. That distance must be mentioned. Otherwise you can not find working distance from prescription.
With 1.50D neutralise axis 55 from 67cm and the other axis neutralized at 40cm .the refractive error is A)-1.50/-1.50*55 B)-1.50*55 C)+2.50/-1.00*145 D)-2.50/+1.00*55 Sir Pls help me .
I do not know the book name. But not every thing should be with reference to some books. With expertisein your field, you can devise your own methods also. Which you feel are easy to understand. The main thing are the results which remain same whether you use this method or the other one.
It depends upon which meridian you consider as reference meridian to calculate refractive error. In the video, i have considered vertical meridian as reference. So axis taken are 90. If you consider horizontal meridian as your reference, you will write axis 180.
You choose one meridian to subtract your working distance and since that is the reference meridian you already addressed that issue by the subtraction of the difference in meridian when you finally arrive at the axis, there is no need to subtract working distance from the two meridians.
Too much confusing... We can Simplify it more easier way, e.g +400×180+300×90 Difference number concider as cylinder So +300+100×180 Now add working distance 66cm -150 +150+100×180
