I had read about this place on happycow, and ate here twice on a past trip to Prague. Here's my Lehka Hlava review.
My husband and I had excellent dining experiences both meals. The ambiance of the restaurant is modern, clean, and pleasant.
The food was tasty and satisfying and in good portions. We dined once in the orange room, and once in the colorful modern room. The menu offered a variety of choices (in English, too). The dishes we ordered were: the house special mint lemonade, freshly squeezed carrot-ginger juice, the goat cheese salad, tempeh bulgar risotto, spinach with goat cheese atop potatoes gratin, and marinated skewered vegetables with couscous. All very good and reasonable prices.
If you come to Prague, definitely eat at Clear Head. I've added it to my list of Top 10 Favorite Veg Restaurants.Pros: good vibes, good food, good service