There are many reasons for red blood in the eyes and more pain, it can be conjunctival and scleral diseases, such as conjunctivitis, conjunctival foreign body, scleritis, conjunctival stones and so on. It can also be caused by diseases of the eyeball such as keratitis, iridocyclitis, glaucoma, etc. All of which can cause dilation of capillaries, congestion and pain in the eyes. From the source of the disease can be bacterial, viral, chlamydial, mycoplasma, autoimmune and other causes of capillary dilation and pain. Normally, prolonged late night, poor rest, long time looking at the cell phone, computer, excessive use of eyes, smoking, drinking and the external environment of chemical gas stimulation can also cause vasodilatation. You can use some anti-inflammatory drops, such as chloramphenicol eye drops or tobramycin eye drops, pay more attention to rest, do not eat spicy and stimulating food, if there is no improvement in 3-5 days, it is best to go to the hospital for examination.