The focuser of your telescope is used to correct one's nearsighted or farsighted vision, so that if you're lucky enough to only have plain old nearsighted/farsighted vision you can enjoy observing through the eyepiece without your glasses. But what of those poor folks whom have an astigmatism correction within their glasses prescription? They have historically just had to tolerate their glasses, allowing more stray light into the viewing experience as well as adding two reflective surfaces to steal their little share of the light reaching your eye as well.
But no more. Thanks to Tele Vue's ingenuity, the DIOPTRX astigmatism correcting lens now allows those with astigmatic vision to enjoy the sharpest viewing experience they've ever had, without using their glasses! Simply choose the DIOPTRX model that matches your eyeglasses' prescription for astigmatism and you'll be ready for a new level of enjoyment.