Lighting a memorial candle for departed loved ones on the Hebrew anniversary of their deaths is a very widespread Jewish practice. However, the way we do it might be missing the point.
The Rosh, Rabbeinu Asher, wrote in the14th century that it is good to donate candles and oil lamps to the synagogue for use on Yom Kippur, "to atone for one's mother and father". However, the Kolbo, a collection of halachic rulings, says that the reason is that people will be able to pray and study Torah for longer and this will bring merit on the donor's ancestors.
The former Sephardi Chief Rabbi of Israel, Benzion Uziel, states explicitly that this is the point of yahrzeit candles. Rabbi Ovadia Yosef wrote that these days the same purpose can be fulfilled by giving money towards covering the shul's electricity bill. It seems then that the goal of yahrzeit candles is not the light itself, but the spiritual light that it helps to spread.