1. What is Near PD?

Definition: Near Pupillary Distance (Near PD) is the distance between the centers of your pupils when focusing on a near object, typically 3mm less than your Far PD.

Purpose: This measurement is essential for properly fitting reading glasses or progressive lenses to ensure optimal vision for close-up work.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• Near PD — Pupillary distance for near vision (mm)
• Far PD — Pupillary distance for distance vision (mm)

Explanation: The eyes converge slightly when focusing on near objects, reducing the measured distance between pupils by approximately 3mm.

3. Importance of Near PD

Details: Accurate Near PD ensures proper optical center alignment in reading glasses, reducing eye strain and improving comfort during close work.

4. Using the Calculator

Tips: Enter your Far PD measurement in millimeters. This is typically measured by an optician during an eye exam.

5. Frequently Asked Questions (FAQ)

Q1: Why is Near PD different from Far PD?
A: When focusing on near objects, your eyes naturally converge (turn inward slightly), making the pupil distance measurement smaller.

Q2: Is the 3mm reduction always accurate?
A: While 3mm is a standard average, individual variations exist based on reading distance and personal physiology.

Q3: How do I measure my Far PD?
A: Far PD is best measured by an eye care professional, though some online tools can provide approximate measurements.

Q4: Does Near PD change with age?
A: The relationship between Far PD and Near PD generally remains consistent, though your reading distance may change.

Q5: When is Near PD not needed?
A: Single vision distance glasses don't require Near PD, but progressive lenses and reading glasses do.