Differentials

Revision as of 22:52, 20 June 2020 by Lajos (talk | contribs)
Jump to navigation Jump to search
Without diffs, you're on the path to ever increasing prescriptions and will get nowhere with vision improvement :(

Differentials are reduced strength glasses for close up activity. They have a lower correction than your normalized lenses that allows you to see clearly only up to the screen. The difference between normalized and differential lenses is usually between 1 and 2 diopters.[1][2]

People with myopia of -2 D and lower do not typically need to wear differentials (because with -2 D your distance till blur should be around 50cm - far enough to see your screen with sufficient clarity).

If you are wearing contact lenses, it is recommended to use plus lenses of a suitable power over the contacts as differential glasses.

Why are differentials worn?

The primary stimulus for axial elongation of the eyeball is hyperopic defocus, which occurs when someone:

  • Is engaged in close-up activity
  • Wears more correction than they need to when seeing the object that is close up.

Differentials allow the wearer to wear just what they need to, to see up close. This removes the stimulus of hyperopic defocus, and stops eyes from getting more myopic. In a sense, it's a quick fix. Face-wink.svg

It's fairly easy to stop myopia from progressing, by just wearing differentials. The axial length of the eye does not randomly change by itself, it only changes in response to stimulus.

See also

Guide:Reducing differentials

References