Reduction

Revision as of 18:08, 22 October 2021 by Angel (talk | contribs) (→‎When to reduce: added link to further reading)
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Your Normalized and Differentials Lenses power should steadily reduce in power over time. (+0.25 for myopes, -0.25 for hyperopes, moving towards 0) Meaning your correction should be a quarter diopter weaker than what you need to see clearly and this provides a slight blur stimulus for change.

When to reduce

As your eyes improve, you will need to reduce again to maintain that slight blur. These reductions typically occur every 3-4 months, and should alternate between differentials and normalized with 4-6 weeks of adjustment period between changes to your focal plane. It is important to be sure you are ready to reduce and that your measurements justify reduction. Reducing too soon is never a good idea (see blur adaptation). Ideally, you should be consistently (for a week or two) seeing 20/20 in your current correction, indoors, with reasonably good lighting, on a 20 foot or 6 meter chart. The 20/20 doesn't need to be ultra sharp, remember being able to identify half or better on a line is a pass, but make sure you are only giving yourself credit for letters you can actually see; preferably without active focus.

further reading

How to reduce

Once your measurements justify that reduction you want to start out with the new correction properly, which is why it is best to perform a "zero diopter reset".