<prompt> Pin hole test is used for:KeratoconusRefractive errorPresbyopiaonly Astigmatism  <response>: 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 