Ophthalmology General 7e2b2197 In retinoscopy for refractive error at 1m, we add 1D ; if done at a distance of 66 cm, the additional factor will be – A –2 B –1.5 C –0.5 D –5 High-Yield Explanation Deduction of 1D for lm and 1.5D when retinoscopy is performed at 2/3rd m (67 cm) distance.