Thank you Dr Arup 🙏

1. New sphere = alegrebaic sum of sphere & cylinder = 0 + (-1.50) = -1.50 2. New cylinder is numerically same with opposite sign = +1.50 3. Rotate cylinder through 90 0 4. So if prescription is 0 / -1.50 x 180 a. Spherical Equivalent → -1.50 / +1.50 x 90 5. If prescription is 0 / -1.50 x 90 a. Spherical equivalent →-1.50 / +1.50 x 180

@@ophthalmologypearls thanks

That is not correct,this is true if you want to change the -/+ sign of the prescription.the correct SE is -0,75sph

@@alexlagogiannis3682 please explain

Sorry I am not familiar with optometry syllabi

Yes

@@ophthalmologypearls so mam does it also mean if i have -1 cy only it will work as -0.5 spherical?

The spherical equivalent is -0.5 D