The majority of eye diseases do not exhibit visible physical symptoms but present vision issues, according to BootsWebMD. Cataracts, however, manifest with a cloudy spot in the middle of the eye. Lazy eyes, styes and conjunctivitis are additional diseases that clearly display physical symptoms.
Cataracts are a common vision and ocular disease with visible symptoms. This problem represents a buildup of protein on the ocular lens, explains BootsWebMD. In addition to a visible spot on the lens, the victim's vision becomes scattered, resulting in poor vision.
There are two primary causes for lazy eyes, both resulting in physical manifestations. Simple misalignment of the eyes is called strabismus, notes BootsWebMD. Additionally, having one weaker eye causes lazy eyes. This eye disease presents itself with one eye crossing the gaze of the second.
Conjunctivitis is another ocular issue visible to the naked eye. This problem is actually a catch-all term for any eye inflammation, states BootsWebMD. Potential causes of conjunctivitis include allergies, viruses, bacteria and irritants. The affected eye becomes red and itchy and typically releases a discharge. Both bacterial and viral inflammations are contagious. Styes are a related inflammation issue, but they only affect the health of the edge of the eyelid.