Reflector sight

Since their invention in 1900, reflector sights have come to be used as gun sights on all kinds of weapons. They were used on fighter aircraft, in a limited capacity in World War I, widely used in World War II, and still used as the base component in many types of modern head-up displays. They have been used in other types of (usually large) weapons as well, such as anti-aircraft gun sights, anti tank gun sights, and any other role where the operator had to engage fast moving targets over a wide field of view, and the sight itself could be supplied with sufficient electrical power to function. There was some limited use of the sight on small arms after World War II but it came into widespread use after the late 1970s with the invention of the red dot sight, with a red light-emitting diode (LED) as its reticle, making a dependable sight with durability and extremely long illumination run time.

Question: did they have red dot sights in ww1
Answer: no