What Causes Dizziness After Having Latanoprost Drops?

I have been taking Latanoprost drops since July, 2014 and have been having dizziness and tightness from my pulses to the bottom of my neck like someone is pressing my head on both sides and my inner ear is tight. Tightness from both sides of my head. All over feeling of discomfort. I am a very young 71 year old woman. I was treated for dizziness and that has almost completely disappeared.