The eyes are an amazing organ, without them, sight could not be possible. While most animals share the same senses as us, most of them are not visual-first like humans are. Most of our mammal brethren usually rely on smelling and hearing - that is the main way how they perceive reality. Humans are rare in that we try to rely on visualization to get around. This is also why our eyes are much more developed than our ears or noses.
Everyone can have a sty from time to time, especially if you exercise, sweat, or are otherwise not hygienic enough. This is not a problem, although having a permanent stye is - in many cases that could be a sign of sebaceous gland carcinoma.
This one is slightly more worrying - I imagine the panic I would be having if I discover that I have parts of my eyebrow hair falling off! Anyway, eyebrow hair loss can be a sign of aging, stress or a serious nutrition deficiency.
Acute blurry vision is not really a problem - there could be many benign causes behind this, such as getting sleepy, waking up, or being too tired or drunk. If you do have a frequent blurry vision, that is more serious. It could indicate a "dry eye syndrome."
This is similar to what you may have heard drivers talk about - even the best and most expensive cars can have blind spots - that is when you can't see at certain angles in the rearview mirror. In people, blind spots can be a sign of an impending headache.
This one is very scary, especially if it makes you look like you have Down's Syndrome or something. In many cases, having bulging eyes could be a sign of thyroid (or Graves) eye disease. If you have this, do check your thyroid.
I've seen this symptom in a few people outside, but I never knew what was it about. I noticed homeless or otherwise poor people have a higher chance of having yellow eyes. What that means is a possible liver problem - either a disease or a potential complete failure.
Saying "cloudy vision," probably makes you want to laugh, but the situation is, sadly, much direr. This can be a symptom of diabetes, called "diabetic retinopathy," a state where the blood vessels in your eyes get increasingly damaged due to the high blood sugar.
I just wanted to drop this note here - no matter what kind of symptom or problem you may be having with your eyes, don't just use the Internet to diagnose yourself. Always talk with your doctor, he is going to know best whether you need further examinations or not.
Here is more serious potential disease - if you are having white spots in the cornea (the black part) of your eyes, this could indicate a possible infection. This can be especially frequent in people that have to wear contact lenses for prolonged periods of time.
If your eyes are twitching, I have good news for you! You are either having a caffeine overdose, are severally anxious, or you are under a lot of stress. Remember, stress and anxiety go hand in hand together, so try to be more chill.
Diabetes is one of the most common diseases to affect ordinary, middle-class people in developed countries. It is caused by a combination of high-carb intake, and low amounts of exercise - blurry eyes can be a possible symptom of Diabetes.
High-cholesterol is also one of the most common health complications in developed countries. One visible sign of high-cholesterol is the formation of a white ring around the cornea of your eye. Take measurements and speak with your doctor if you notice this symptom.
High blood pressure is one of the worst "invisible killers" that exists. You can't notice it by just looking in the mirror, but if you are having headaches or problems with your vision, it could be time to talk with your doctor or to take a blood-pressure measure at home.
This one is pretty easy to guess - if your eyes are becoming dry, and you are starting to rub them more frequently, that could mean your histamines are up. When your histamines are increased, that means you are having an allergic reaction to something.
Having visible, moving specks in your field of view is something that happens to everyone. Some people call these things "floaters." If you are having "floaters" on a frequent basis, that could be a sign that you have damaged your retina and should talk to a doctor immediately.