Prescription & Measurement Tools
Reading ADD Power Explainer
Learn what ADD means for progressive, bifocal, and reading lenses — educational ranges only, not a prescription.
Overview
ADD (addition) is the extra near power combined with the distance prescription in bifocals, progressives, or office lenses. It supports near focus when the eye’s natural accommodation declines — commonly discussed with presbyopia.
This explainer shows educational relationships among age bands, working distance, and typical ADD discussions. It does not prescribe an ADD for you.
How to use this tool
Follow these educational steps:
- Enter an age range and a preferred working distance if the interface asks for them.
- Read the educational estimate as a discussion aid only.
- Compare the concepts with any ADD already printed on your prescription.
- Review why over-the-counter readers are not identical to customized multifocals.
Interactive tool
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What results can mean
Higher ADD values provide more near plus power. Needed ADD also depends on arm length, job tasks, and the distance Rx. Two people the same age can need different solutions.
If the educational estimate differs from your written Rx, trust the clinician’s refraction and binocular assessment.
What results do not mean
This tool does not authorize you to order progressive lenses or to increase ADD on your own.
It cannot detect latent hyperopia, binocular vision disorders, or cataract-related changes that alter near needs.
Limitations
Important limitations:
- Age-based heuristics are population patterns, not personal prescriptions.
- Surgery history and monovision contact lens wear change near strategies entirely.
When to see an eye-care professional
See an eye-care professional when near work becomes effortful, when you hold phones farther away, or when progressives feel wrong at intermediate computer distance.
Frequently asked questions
It means two diopters of near addition over the distance prescription in a multifocal design — interpreted by your clinician for your working distances.
Readers provide near plus without your customized distance/astigmatism correction. They can help some people for simple tasks but are not a full substitute for an exam.
Sometimes near needs or balancing considerations differ; clinicians decide.
Intermediate distances may need a different lens design than a classic reading ADD aimed at 40 cm.
Sources & references
- Adult Vision: 41 to 60 Years of Age American Optometric Association (AOA)
- Refractive Errors National Eye Institute (NEI/NIH)
- Eyeglasses American Academy of Ophthalmology (AAO)
- Eye Care MedlinePlus / National Library of Medicine (NIH)