It seems that there might have been something wrong with your eyes or body health. So, generally speaking, the whites of our eyes would not change their color ,nor do the pupils, but sometimes the whites will be bloodshot due to disordered life. As to their turning grey, the possible reason for this is that you have been much too tired recently. I personally recommend that you consult an eye doctor.
When the whites of the eye change the color, you should pay attention to. The changing grey may imply you that you may get the anemia lacking of Fe. In short, there is something wrong with your cornea. You'd better go to see the doctor as soon as possible, in case of the further infection.
If you have the habit to take in chocolate, soy sauce, cigarettes, tea, coffee, cola or high pigment content of food, your eyes will have pigmentation and turn grey a lot. Levorotatory vitamin C can help the pigmentation.
Anyway, you should turn to a doctor for professional suggestion.
Scleral melanocytosis, amelanotic conjunctival nevi and scleral thinning are three eye conditions associated with gray spots on the whites of eyes.Ocular melanocytosis is a congenital condition that manifests as slate-gray or bluish patchiness on the sclera, the white portion of the eye. Although the condition itself is benign, individuals with it have a higher incidence of glaucoma and are at a higher risk for melanoma. Slate-gray patches caused by scleral melanocytosis are especially common in African-American and Asian children.A nevus, such as one seen in individuals with amelanotic conjunctival nevi, is a pigmented growth on the eye that is usually benign, notes EyeSmart. However, nevi can develop into eye cancer, called ocular melanoma, in uncommon cases. People with nevi should have the growths monitored by a health care professional to ensure early detection if cancer develops.Thinning of the sclera can occur as a result of defects in the way the body synthesizes collagen.Some defects that can lead to this condition include Ehlers-Danlos syndrome, Marfan's syndrome and osteogenesis imperfecta.
As far as i know that aging can cause the change of the eye color - the whites of your eyes turn grey or yellow. But if you are young adult, you should be take care because it may caused by scleritis or the inflammation of the sclera. If so, you need see a doctor and give your a eye check for sure. Just treat your eyes immediately or it will become more serious.