Tomorrow’s the first day of winter and the “shortest” day of the year, meaning it’ll be darker longer. That also means more Iowa motorists will be behind the wheel in the dark, which can strain the eyes — and bring the potential for more wrecks. Des Moines eye surgeon Dr. Brad Hammer says nighttime vision is tough for everyone. Dr. Hammer says Iowa motorists should make sure their headlights and taillights are working — and that they’re clean. He also says it’s important to keep your mirrors and windshield grime-free, and that means on the inside too. Hammer offers yet another reason to give up cigarettes.Smoking can cause a variety of health and eye problems and the smoke itself can put a film on the windows and windshield that can impair your vision. Dr. Hammer says Iowans shouldn’t go speeding out of their garages when it’s dark outside. He says to take a few seconds to let your eyes get used to the darkness. He says this is especially true for older Iowans who may take longer to adjust to changes in the light.For Iowans who wear glasses, he says clear lenses with an anti-reflective coating are the best for night driving, while tinted lenses can be the worst.