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What is What will be the prescription for spectacles in a patient having simple myopic with the rule astigmatism? and explain in detail?
-0.5D at 180 degrees With the rule astigmatism - two principal meridian are at right angles with the veical meridian being more curved. Correction requires convex(+) cylinder at 90 degrees or concave (-) cylinder at 180 degrees. Myopic astigmatism means the patient has to be given a concave cylindrical lens. Against the rule astigmatism corrected by = convex(+) C at 180 degrees or concave (-) C at 90 degrees Option 4 +2.0D at 90 degrees is also with the rule astigmatism but this patient will have simple hyperopic with the rule astigmatism not simple myopic as expected from the question