What commonly causes foggy vision in sunlight?

Dry eye cataracts. Anything which compromises the visual system of the eye may induce fog and glare. Most commonly, the culprits are dry eyes and cataract formation (haziness of the lens).
Foggy. Foggy vision may be caused by glare, incorrect glasses prescription, cataract, corneal edema, glaucoma (untreated), iritis, allergies, trauma, corneal abrasion, dry eye. If your symptoms are persistent, seek care from your local ophthalmologist.