According to Robert Cykiert, M.D., F.A.C.S., monovision works best when attempted in early presbyopia because minimal anisometropia and blurring are induced by the undercorrecting contact lens used for reading. As presbyopia progresses, myopic patients who start on monovision early will usually tolerate undercorrections of up to 2.5D in their non-dominant eyes. Undercorrections greater than these are usually not tolerated, so patients in their late 50s or 60s will usually give up and go back to wearing bifocal spectacles.

Similarly, hyperopes will tolerate a stronger plus prescription in their reading eyes, if they start becoming accustomed to this at a relatively early age. Monovision rarely works if the initial under-or-over correction is greater than 1.25D to 1.50D.

This modality also offers opportunity for increased contact lens sales. Monovision patients will often wear distance contact lenses in their usual reading eyes for activities such as night driving, movies theater – situations when they don't expect to do any reading and when best distance acuity is advantageous for both eyes. Thus, many monovision patients require three types of contact lenses rather than the usual two.