Seeing reflections or glare in glasses, especially when there is light behind you, is a common phenomenon and is generally considered normal. It is known as lens flare or lens reflection.
Lens flare occurs when light sources or bright objects create reflections or scatter within the various lenses of your glasses. This can result in the appearance of halos, streaks, or ghost images around the light source, often with a colored tint. The specific color you mentioned, green, can be one of the colors associated with lens flare, although it can vary depending on the specific characteristics of your glasses and the lighting conditions.
Lens flare is more noticeable in certain situations, such as when the light source is directly in your field of vision or when the lenses of your glasses are dirty or smudged. It can also be affected by the type of lens coating or anti-reflective treatment applied to your glasses.
If you find the lens flare to be bothersome or affecting your vision significantly, you may consider discussing it with an optician or eye care professional. They can examine your glasses, evaluate your visual needs, and provide recommendations or adjustments to minimize the occurrence of lens flare.