Pin hole test is used for:
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
Keratoconus
Refractive error
Presbyopia
only Astigmatism
Optics and Errors of Refraction