Thank God. It's the only way I can find my chocolate lab in a dark yard at night using a flashlight.
Same with my Yellow Lab. His eyes glow golden yellow!
My black poodle disappears in the shadows also.
PetsMart has a fiber optic-like collar powered by a button battery. Works great.
We have used a lighted arm band available at Lowe's . They have a greenish reflective coating and are battery powered glowing also. Continuous or flashing.
Either are about $10.