Hi @mattiarib, thank you for your query. I assume you are working with the older unreal plugin available @ https://github.com/TobiiTechnology/EyeXforUE4 ?
This plugin is now rather old (3 ~Years) so you may experience issues that are difficult to resolve in recent SDK and API versions, however certainly you do not need the Visor VR to make use of this.
Are you aware of the Unity plugin we offer via the Tobii Core SDK? This may offer you the kind of graphics capabilities you are looking for. Please read more @ https://developer.tobii.com/tobii-unity-sdk/
In any event, if you could kindly describe in more detail your hardware setup, error messages and project intentions, we will be better placed to offer further support.