In theory, can you link having consistently red eyes(excluding pink eye,drug use) to any of the following?

Question

Back pain/injury, lack of sleep, prostate cancer, testosterone deficiency, or one "lazy" poor vision eye and one strong one. Links always appreciated, but not necessary.

Answer 1

http://www.nlm.nih.gov/medlineplus/ency/article/001031.htm

Answer 2

no, those things do not cause erythema ( redness) of the eye