Swimming goggles are supposed to keep your eyes safe, not bruise them. If your goggles fit too tightly, though, you can quickly find yourself with sore, bruised eyes and even broken capillaries. The key is to find goggles that fit snugly enough to protect your eyes, but not so tightly that they cause pain.
Why Your Eyes Are Bruised
When there's too much pressure on your blood vessels, they can leak or burst, causing the familiar sight you know as a bruise. The skin around your eyes is thin and delicate, making these blood vessels more prone to irritation and injury. If your goggles are too tight, the pressure can cause bruising, but if they're too loose, they can easily be bumped, causing eye injuries.
Treating the Pain
If your goggles bruise your eyes, then you'll need to lay off of goggles until the pain goes away. Putting on a new pair -- even one that fits correctly -- can exacerbate the pain. Alternate between ice packs and hot packs, twenty minutes on and twenty minutes off for each. If you have trouble seeing or the bruising is severe, talk to your doctor.
The Proper Fit
To avoid bruising your eyes in the first place, you need goggles that fit correctly. The band should be flush against the back of your head, but should not pinch your skin. The goggles themselves should be centered over your eyes and should be snug enough that water can't rush in, but not so snug that your skin feels pinched or you feel pressure in your eye sockets. Sometimes goggles that aren't large enough to fully accommodate your eyes can cause pressure, so err on the side of larger goggles.
You should wear your goggles only when swimming and not when playing sports in or out of the water. Doing so increases the risk of your goggles being bumped and your eyes being injured. Similarly, if your goggles cloud up, you need to take them off. If you can't see, you're more likely to run into something with your goggles and risk injuring your eyes.