Your optician's advice about the -1.00 prescription being "healthier" is not supported by evidence—contact lenses should be prescribed to fully correct your refractive error, not undercorrected.
The Problem with Undercorrection
Contact lenses must be prescribed according to your actual refractive error to provide optimal vision and eye health. The 2023 American Academy of Ophthalmology guidelines emphasize that contact lens fitting requires careful attention to optimizing the prescription to provide the best vision and fit 1. There is no evidence that deliberately undercorrecting your prescription (using -1.00 instead of your full correction) provides any health benefit to your eyes.
What the Evidence Shows
The guidelines are clear about contact lens prescription principles:
- Proper fitting requires accurate refraction: Keratometry and refraction measurements should be compared to determine the correct prescription that will provide optimal vision 1
- Daily disposable toric lenses are the safest option: These lenses have emerged as the type least likely to be associated with infectious or inflammatory complications, causing less ocular surface damage compared to reusable lenses 1
- Full correction improves functional vision: Recent research demonstrates that proper toric correction (versus undercorrection with spherical equivalent lenses) provides significantly better visual acuity, fewer reading errors, and reduced visual fatigue during near tasks 2
Why Undercorrection Is Problematic
Using a -1.00 prescription when you need more correction will:
- Compromise your visual acuity: Both high and low contrast vision are significantly better with proper toric correction 2
- Increase visual strain: Studies show greater focusing demand and signs of visual fatigue with undercorrected prescriptions during prolonged visual tasks 2
- Provide no health benefit: There is no evidence in the literature that undercorrection prevents complications or improves eye health
The Right Approach
You should wear contact lenses that match your actual prescription as determined by proper refraction. If you're using daily disposable toric lenses, the evidence strongly supports this modality as it provides 1, 3:
- Lower risk of infectious and inflammatory complications
- Less ocular surface damage
- Reduced exposure to deposits and contaminants
- No need for disinfection protocols that increase complication risk with non-compliance
Common Pitfall to Avoid
Some practitioners may suggest slight undercorrection based on outdated concepts or personal preference, but this is not evidence-based practice. The prescription should be based on objective refraction findings and what provides you with the best corrected vision, not arbitrary reduction of cylinder power.
If your optician cannot provide a clinical rationale supported by your specific examination findings for why -1.00 is appropriate for your eyes, you should seek a second opinion from an ophthalmologist or optometrist who will prescribe based on your actual refractive error.