We only provide suitable lighting if the customer requests it. Lighting is such an application specific solution that it does not make sense to include generic lighting with every order. 

Does the light influence reflect on system efficiency?  Is it necessary to work in a dark environment?  

Lighting is important.  The more you control the lighting, the more sensitive Eyebot will be.  The more variety you show, the less sensitive it becomes.  Therefore, you can train it under varying lighting conditions, but you will pay the price of diminished sensitivity.