Hello, It is good to know that the irregular dark patch is not affecting the line of vision. You are suggested to get it clinically examined by an eye specialist. You may have to get a few required investigations and imaging tests done to detect possible pathology that is causing you symptoms like pinguecula, subconjunctival hemorrhage, broken blood vessels, acquired malanosis, freckles, etc. Dark spots that appear over the white areas of the eyes can be usually benign growths of the pigment producing cells known as melanocytes. They may be freckles, benign melanosis, ocular melanosis that are not sight threatening condition in the majority of the cases. However, get assessed and treated if required. Take care. Hope I have answered your question. Let me know if I can assist you further. Regards, Dr. Nupur K., General & Family Physician