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Published on: March 25, 2011
From line to dots: an improved computerised rod and frame system for testing subjective visual vertical and
1AECC, 13-15 Parkwood Road, Bournemouth, BH5 2DF, UK. sdocherty@aecc.ac.uk
BMC Research Notes
|March 9, 2010
Summary
The computerized rod and frame (CRAF) system was adapted to measure subjective visual horizontal (SVH). Replacing the visual rod with two dots improved accuracy for both SVH and subjective visual vertical (SVV) measurements.
Area of Science:
- Neuroscience
- Perception Science
Background:
- Traditional methods for measuring subjective visual vertical (SVV) and horizontal (SVH) involve mechanical rods.
- The computerized rod and frame (CRAF) system was previously limited to SVV measurements.
Purpose of the Study:
- To adapt the CRAF system for measuring SVH.
- To evaluate the impact of visual presentation on SVV and SVH measurements.
Main Methods:
- 103 subjects were randomly assigned to test SVV or SVH using the CRAF system.
- A second investigation with 30 subjects compared a line rod to a two-dot presentation for SVV and SVH.
- Bland and Altman analysis was used for comparison.
Main Results:
- Preliminary SVH measurements showed a high percentage of errors, attributed to visual cues from the rod.
- Replacing the rod with two dots reduced measurement errors for both SVV and SVH.
- The two-dot presentation yielded SVH errors comparable to manual systems.
Conclusions:
- The CRAF system can be effectively used to measure SVH.
- Replacing the line rod with two dots enhances the system's accuracy by minimizing visual cues.
