Pin hole test is used for:: (A) Keratoconus, (B) Refractive error, (C) Presbyopia, (D) only Astigmatism
Answer is B. PIN HOLE TEST - Completely opaque plastic device with central hole (1mm diameter) - It allows single ray of light that passes through nodal point of eye. - On applying this if vision improves = optical error ( Myopia , Hypermetropia, Astigmatism) if vision do not improves= organic error (macular disease, dense cataract, retinal detachment, retinal diseases) It does not differentiates type of optical error