Eyes are not only associated with vision but can act as windows to our health as well. Apart from providing hints about diminishing vision, glaucoma and dry eyes, there are various health complications that your eyes can often be the first indicators of. Of the many diseases, most conditions can be revealed by simply looking into the mirror and carefully observing your eyes. Here are few common diseases whose first symptoms might be seen in your eyes. Bug eyes: Clinically known as exophthalmos, bug eyes are one of the common symptoms observed in case of an overactive thyroid such as Graves’s disease.