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VR GLOSSARY
Definition

PPD — Pixels Per Degree

Number of pixels displayed per degree of field of view, an indicator of perceived sharpness

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PPD — Pixels Per Degree

Explanation

PPD (Pixels Per Degree) measures pixel density per degree of angle in a headset's field of view. It is the most relevant indicator for evaluating perceived sharpness — more reliable than raw screen resolution. The human eye perceives roughly 60 PPD: below that, individual pixels are visible (the screen-door effect). Current headsets range from 20-25 PPD (Quest 3) to 40+ PPD (Vision Pro), with the goal of exceeding 60 PPD for images indistinguishable from reality.

Real-world example

The Meta Quest 3 displays approximately 25 PPD: text is readable but pixels are still perceptible up close. The Apple Vision Pro reaches 34 PPD, making text reading comfortable.

Practical applications

  • Text readability: a high PPD makes text-based interfaces usable in VR
  • Visual detail: spotting defects on an industrial part in VR
  • Visual comfort: less fatigue when the image is sharp
  • Headset comparison: PPD is more meaningful than raw resolution

PPD of current headsets

Entry-level (15-20 PPD)

  • Visible screen-door effect
  • Text difficult to read
  • Adequate for dynamic experiences

Example: Quest 2: ~20 PPD, fine for games but limiting for work

Mid-range (20-30 PPD)

  • Readable text
  • Fine details perceptible
  • Current standard for training

Example: Quest 3: ~25 PPD, good balance for training and productivity

High-end (30+ PPD)

  • Very sharp image
  • Approaching natural vision
  • Ideal for productivity and detail work

Example: Apple Vision Pro: ~34 PPD, text as sharp as a retina display

VR scenario

An architect compares two headsets for project reviews. At 20 PPD, they cannot read the dimensions on plans displayed in VR. At 34 PPD, every number is crisp. They choose the high-resolution headset for clients who demand detail.

Why it matters in professional VR

  • PPD is the key indicator of perceived visual quality in VR
  • The 60 PPD target (retinal acuity) is the threshold for images indistinguishable from reality
  • Insufficient PPD limits productivity use cases (reading, detail, inspection)
  • PPD depends on both screen resolution AND field of view