What would be the cause of feeling pressure behind the eye?

What would be the cause of feeling pressure behind the eye? My eye feels very dry and there is some redness. Feels, but does not look swollen. There is also pressure in the sinuses. Mainly on the left side.

This is a tough question because many things can cause a feeling of pressure behind or around the eye. Conditions can range from minor conditions like ocular surface dryness to very concerning things. It is important to see your ophthalmologist. Try to document and describe as many factors surrounding the condition prior to the visit. Things like the type of pain, duration, initial onset of the symptoms, things that make it better or worse, and medications you use are all critical to help your ophthalmologist figure out what is going on.