FAQ: How do the EyeLink system and Data Viewer calculate degrees of visual angle?

[Sam]

The EyeLink system and Data Viewer calculate visual angles and velocities based on two key parameters: viewing distance and screen dimensions. To ensure your data is accurate, it is critical that these values are specified correctly in your Host PC's configuration settings.

Where to Configure Settings
The location of these settings depends on your EyeLink model:

• For EyeLink 1000 Plus & Portable Duo: Set the parameters on the Screen Settings page within the tracker's Configuration Manager.
  
• For EyeLink 1000 & EyeLink II: Set the parameters in the PHYSICAL.INI file located on the Host PC.
  

For detailed instructions and further reading, please refer to the following resources:

• Step-by-step Guide: Configuring Screen Settings in the .INI file
  
• General Concept: Blog Post: What is Visual Angle?
  
• Hardware-Specific Installation Guides:
  • EyeLink Portable Duo
    
  • EyeLink 1000 Plus
    
  • EyeLink 1000
    
  • EyeLink II