LED lights may be more efficient and long lasting, but they emit more short visible wavelengths (ie: blue light) than other light sources. Blue lights scatter more especially in fog and rain. You will notice more halos and glare and feel these lights are very harsh, especially for people who have mild cataracts.
Anti-reflection coating on glasses can help reduce some of the glare and halos. It is best to not look directly at these lights and to take extra caution when driving at night.
Little data is available with regards to the health effects of these lights.