to be a bit more general:
If you want to use an image with a radiance tool (in your case evalglare, but it is the same for any other) you have to make sure that :
a) the projection method of your lens corresponds to a supported radiance projection method (e.g. angular fish-eye-> vta, hemispherical fish-eye -> vth or perspective projection -vtv
b) you know the real opening angle of your lens and put these “real” values as vv and vh parameters in the header.
Only with these information any angle and glare metric can be calculated correctly, whatever tool you apply.
To determine both please follow the instructions in the tutorial paper.
Evalglare can actually handle all angles, even if they are smaller than 180. Of course if your lens is smaller than 180° you cannot calculate the Ev corectly any more - the smaller the angle, the larger the mistake.
For DGP calculations you can provide evalglare also with an external measurement value (e.g. if you use the 133° lens), but this is not recommended due to the reasons mentioned above.
As mentioned, evalglare was mainly published to enable people to calculate glare from simulated scenes, that’s why the 180° should be used for simulations - it does not mean it cannot handle other angles. You have to put the real angles in the header.
In short: The header should always reflect the reality of the lens, how should the program otherwise know what lens you used?