lubricant eye drops. It's the most gental and effective for long term use, because it's preservative free, as the pic shows the single use vial. The preservative itself in many eye drops for dry eyes can cause irritations. I've tried all available over the counter eye drops, this is the top quality and works best for me. The most the ophthalmologists i've known use this.
http://www.refreshbrand.com/Products/optive-advanced-preservative-free