Why PD Accuracy Matters
Pupillary Distance (PD) is the measurement used to align your lenses precisely with your eyes inside the frame.
This data ensures that the optical center of each lens matches the natural position of your pupils — a key factor for comfort and visual clarity.
If the PD value is incorrect, lens centering will be off, which can cause:
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Eyestrain
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Headaches
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Muscle tension or neck pain
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Blurry vision
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Even migraines in some cases
This data is very important, it is used to correctly center the lenses on the frame.
If the centering is not right, inconveniences are inevitable: eyestrain, headaches, muscular pains, migraines and blurry vision.
When Slight Deviations Are Acceptable
For low-prescription lenses (especially unifocal ones), small PD variations are usually tolerated.
A deviation of up to 3 mm typically has minimal impact on comfort or vision quality.
When Accuracy Becomes Critical
For high prescriptions or progressive lenses, PD accuracy is crucial.
Even a small error can significantly affect vision comfort and may intensify symptoms like eyestrain or distortion.
That’s why FittingBox strongly recommends obtaining the most accurate PD measurement possible.
The Solution: PD Measurement by FittingBox
The PD Measurement solution provides a highly accurate measurement (within ±2 mm), ensuring lenses are perfectly centered for an optimal visual experience.
