• Are lined bifocals or progressives better for prism?


    Question:

    I have progressive eyeglasses (glasses correcting for more than one distance) with prism. The prism corrects for the far vision, but overcorrects for the near vision causing a shadow image. My doctor recommends lined bifocals now. Are lined bifocals or progressives better for prism?


    Answer:

    There are many factors that would affect your decision, such as direction of prism, type of strabismus, your prescription, prior success with progressive vs. lined bifocals, and target distance of correction (computer/driving, etc.). 

    In general, a lined bifocal has benefits over a progressive lens when correcting for double vision with prism. These include a wider viewing range, as progressives only have a specific point with the clearest vision. Also, because strabismus can change depending on the direction an individual looks, a lined bifocal can fuse the images from each eye more easily into one. 

    The downside to a lined bifocal is the loss of the diverse focus points such as computer distance. Sometimes, a lined trifocal can be tried. Lastly, others with double vision need different sets of glasses as the prism correction changes depending on the distance being viewed. If the option of a lined bifocal does not address all of your issues, you might expect this option to be considered next.