version will only increment when I make major changes. However, the
release date is updated whenever anything changes. Find the release date at the main screen, top right; or use the
About button – there not only FrACT₁₀’s version date is given but also the versions of embedded frameworks. The export format has its own version scheme, the exported data set starts with this version number; this allows your analysis software to easily deal with changes here.
When the window is on the second screen, you can use the
Fullscr. button to go fullscreen. Also note: repeat size calibration (“plastic card / blue ruler”) on the 2nd screen – its pixel size might be different.
Enter a negative value for the Weber contrast in Settings>Acuity>Optotype contrast, e.g. with the
Yes, but you need a visual display unit (VDU) with really tiny pixels. In the Manual there is a note on display resolution… on this, with examples of suitable VDUs.
The technical limitation is screen size and distance. Going close and using a large screen can bring you into ultra-low vision range. Then the problem arises if the observer has sufficient vision. Here is a discussion on this.
Settings>Display Transformation to compensate for the image inversion. [Need to use surface mirrors to avoid double images.]
This was a real question… and the answer is difficult. First: it depends on the size (Diameter), defaulf 60’. Second: an optotype (be it letter, Landolt C, tumbling E…) does not have a spatial frequency, rather it is a mixture (I’ve calculated the spectrum but never published it).
I see two possible scenarios:
Length of blue ruler) and
Observer distancecombine to a very large optotype, and you see only its empty center
Optotype eccentricitysetting is too large, shifting the optotype off screen.
If nothing rings a bell, use
Settings>Set all to defaults: Now you should something, and you can proceed to apply your preferences in