In normal circumstances the eyes of cats, dogs, and people continuously produce tears. Tears keep the eye moist and nourish the cornea (the front portion of the eye). The tears drain through a duct into the nose.
Tears are made up of water, mucus, and fat. Over time, some of the water evaporates. This leads to dried conglomerations of mucus and fat adjacent to the eye. These so-called eye boogers develop in all cats, dogs, and people periodically. People simply rub them away from their eyes. Since dogs and cats don’t have hands, their dried mucus and fat builds up.
If your cat’s eyes are not red, uncomfortable, itchy or swollen, I don’t think you should worry. Asymmetrical accumulation of debris usually is related to irregular drainage of tears through the duct on one side. This generally isn’t a cause for concern. You can remove the debris gently with a moistened cotton ball.
Remember, however, that eyes are very sensitive and fragile. If you have noticed itching, swelling, squinting, redness, discomfort, or any other irregularities, the safest option is to have a vet look at your cat.
Photo: Captain Jack’s right eye looks healthy.