optically
adv.in a way that relates to how light works or how things look. You use this when talking about how light travels or how a lens changes an image.
adv.in a manner relating to the properties of light or the science of vision. Often describes the behavior of light as it interacts with materials or the performance of optical instruments.
“The new glasses are optically perfect.”
“The scientist studied how the material reacts optically when exposed to different wavelengths of light.”
“While the lens is optically superior, its physical weight makes it impractical for handheld photography in low-light conditions.”
“Roman was designed to remain optically stable while rapidly moving from one observation to another.”
“When an intense XUV laser pulse passes through an optically dense medium—such as an atomic gas—it quickly excites and de-excites the atoms' energy levels.”
From optical + -ly.
Etymology adapted from Wiktionary, available under CC BY-SA 4.0.