It is probably not a problem unless you have angle closure glaucoma. You need to ask your ophthalmologist what type of glaucoma you have.

The active ingredient in Astelin is the antihistamine azelastine. Sometimes antihistamines will dilate the pupils.

If you are at risk for angle closure glaucoma, a dilated pupil can cause a sudden rise in pressure within the eye.

Normally, the eye produces a certain amount of fluid each day. This same amount of fluid is reabsorbed in a narrow space just below the iris (the colored part of the eye). People with angle closure glaucoma are prone to having this space become totally blocked.

The blockage stops eye fluid from being reabsorbed. But because the eye continues to make new fluid, eye pressure builds up, sometimes very rapidly. If untreated, this could cause a loss of vision.

If you have the more common type of glaucoma, called open angle glaucoma, Astelin should not pose a problem.