Is it safe to use "Redness Relief" eye drops regularly?

The short answer is NO.

Here’s the slightly longer answer.

There are several eye “Redness Relief” products on the over-the-counter market, such as those made by Visine, Clear Eyes, and Bausch & Lomb - as well as generic versions sold by pharmacy chains.

Most commonly, the active ingredient in redness relief drops is either Tetrahydrozoline or Naphazoline. Both of these drugs are in a category called sympathomimetics.

Sympathomimetics, the active ingredient in redness relief drops, work though a process called vasoconstriction, an artificial clamping down of the superficial blood vessels on the eye surface. These blood vessels often dilate in response to an irritation. This increase in blood flow is trying to help repair whatever irritation is affecting the surface of the eye. Clamping down on those vessels by using a vasoconstrictor counteracts the body’s efforts to repair the problem.

The other downside to...

What does blood in the back of the eye signify, anyway?

It could be a retinal vein occlusion, an ocular disorder that can occur in older people where the blood vessels to the retina are blocked.

The retina is the back part of the eye where light focuses and transmits images to the brain. Blockage of the veins in the retina can cause sudden vision loss. The severity of vision loss depends on where the blockage is located.

Blockage at smaller branches in the retinal vein is referred to as branch retinal vein occlusion (BRVO).  Vision loss in BRVO is usually less severe, and sometimes just parts of the vision is blurry.  Blockage at the main retinal vein of the eye is referred to as central retinal vein occlusion (CRVO) and results in more serious vision loss. 

Sometimes blockage of the retinal veins can lead to abnormal new blood vessels developing on the surface of the iris (the colored part of your eye) or the retina. This is a late complication of retinal vein blockage...