The doctor gave me the phoropter because he purchased a repalcment..I had worked in his office for several years-part time-assisting with refractions!
My RX is very constant--I (as well as my ophthalmologist/optometrist) have "checked " it several times during one day--
All I can say are my personal experiences with optometrists- (4) -each has "overcorrected" (over plussed) my rx..and..one gave me my glasses with the prism correction in the wrong direction and failed to correct it (sent glasses back to lab, glasses returned with prism still in wrong direction!!)
I guess it's the lucjk of the draw
