Another option is Vyzulta, which consists of latanoprost and a NO (nitric oxide) donor. Vyzulta has helped some patients reduce their IOP even further beyond just what latanoprost (or the other prostaglandins alone) can achieve. However, Vyzulta it has not been as effective for everyone. Since we all respond differently, your mileage may vary. Hopefully, it works for you.
In my case, Vyzulta is even more effective than any of the single-active-ingredient prostaglandins mentioned in my other answer here. I did not mention it in that answer because Vyzulta is not a pure prostaglandin drop.
As for a preservative-free version of Vyzulta, none exists and the patent has not expired yet so don't hold your breath.
Anyways, Vyzulta is a good option for many people, including me. However, it's very expensive and not always covered by insurance.
A FitEyes member reports that his insurance (Anthem Blue Cross) does not cover it, unfortunately.
One can also buy it from reputable Canadian on-line pharmacies (we have discussed this before on FitEyes) for a fraction of the price offered in the US and in some cases cheaper than with insurance coverage. One can also go the route of manufacturer coupons if you are not on Medicare and you qualify.
Thanks to Amin for all this information (via the FitEyes email discussion).