Pink EYe can occur due to various bodily diseases, especially those of allergic origin, so the excess fat in seborrheic dermatitis can reach the eyes when, after the front touch us spend our hands on them.
Mood disorders also cause pink eye, problems such as nervous or emotional stress or severe depression make the pink eye become irritated easily. Bad habits are essential in the cause of this disease: the fact rub eyes periodically causes the bacteria that cause the redness of those entering them. Too much reading in dim light, activities that require a lot of concentration at the same point and the same distance (stare at a monitor for a long time, for example), work performed without natural light, allowing no sunlight manifests itself from time to time in our eyes, among other things, are the cause of pink eye.
Poor hygiene also influences eye, the flush eyes with irritation producing products such as soaps containing detergent or unsuitable for cleaning eye sore eyes. Inappropriate environmental sites may favor the emergence of this disease, working in an environment filled with smoke, dust or contaminants, or even places that have a contrast of light that directly affect the retina. Believe it or not, poor nutrition can cause several eye problems, this along with the combination of aggressive environmental conditions favor the emergence of what we call free radicals that are hampering a clear view

Albinism is a cause.
But in albinism is not rosy for having a color pigment, on the contrary.
Albino people do not produce melanin, which is the substance that pigmented hair and skin when we tan. This substance is what gives color to the eyes. People with eye color green or blue (and rarely purple) has this color have fewer pigment that those who are brown.
Albino people do not produce the pigment, and pink or red eyes is because the blood vessels show through, what we see is the color of blood vessels inside.