PD KnowledgeCenter
Expert guides, research-backed articles, and practical tips about pupillary distance measurement and eyewear fitting.
Featured Articles
What Is Pupillary Distance? The Complete Guide
Everything you need to know about PD—what it is, why it matters, and how it affects your glasses prescription.
How to Measure Your PD at Home: 5 Proven Methods
Step-by-step instructions for measuring pupillary distance accurately without visiting an optometrist.
All Articles(19)
Why PD Matters for Your Glasses: The Science Explained
Understanding the optical science behind pupillary distance and its impact on vision quality.
Monocular vs Binocular PD: Which Do You Need?
When single PD works and when you need separate measurements for each eye.
PD for Progressive Lenses: Why Precision Matters More
Special considerations for measuring PD when ordering multifocal or progressive glasses.
7 Common PD Measurement Mistakes (And How to Avoid Them)
The most frequent errors people make when measuring pupillary distance and their solutions.
Why Your Optometrist Won't Give You Your PD
The business and medical reasons behind this common frustration—and what you can do about it.
How Accurate Are Online PD Measurement Apps?
A technical analysis of smartphone and web-based PD tools compared to professional measurements.
Children's PD: Special Considerations for Kids' Glasses
How pupillary distance develops in children and what parents need to know.
PD Errors and Eye Strain: The Hidden Cause of Your Headaches
How incorrect pupillary distance contributes to visual discomfort and what to do about it.
Average PD by Age and Gender: What the Research Shows
Comprehensive data on pupillary distance norms across different demographics and populations.
PD for High Prescriptions: Why It Matters Even More
Special considerations for people with strong prescriptions where PD accuracy is critical.
10 PD Myths Debunked: Separating Fact from Fiction
Common misconceptions about pupillary distance and the truth behind them.
Buying Glasses Online: Your Complete PD Guide
Everything you need to know about PD when ordering prescription eyewear from online retailers.
PD for Reading Glasses: Near Vision Explained
Understanding near PD and why reading glasses have different requirements.
PD for Computer Glasses: Optimizing Your Digital Workspace
How to get the right PD for intermediate-distance computer and office glasses.
The History of PD Measurement: From Rulers to AI
How pupillary distance measurement evolved from simple tools to modern technology.
Single PD vs Dual PD: Understanding the Difference
When one number works and when you need two separate measurements.
Does Your PD Change with Age? The Truth Revealed
How pupillary distance develops from childhood through adulthood.
PD for Prescription Sunglasses: Everything You Need to Know
Special considerations when ordering prescription sunglasses online.
PD and Face Shape: How Your Facial Structure Affects Your Glasses
Understanding the relationship between face shape, PD, and frame selection.
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