Leukocytosis is a term used to describe a condition in which an affected individual has an elevated count of white blood cells in their body. White blood cells are the type of cells that make up an individual's immune system and defend their body from foreign pathogens. There are five types of leukocytosis. When the number of neutrophils is elevated, it is called neutrophilia. Lymphocytosis is when the number of lymphocytes in the body is elevated. Monocytosis describes a state in which there are too many monocytes. Eosinophilia describes an elevation in the number of eosinophils in the body. When basophils are elevated, the condition is called basophilia.
All of these different types of white blood cells have different functions that come together with other components to form the immune system. Leukocytosis or any combination of high white blood cell counts can cause the blood to become too thick to flow adequately.
An individual affected by leukocytosis may present with vision issues as a symptom manifestation of their blood condition. The eye is supplied by a network of tiny capillaries that carry nutrient and oxygen-rich blood to its cells. Some of the smallest blood vessels in the body are located within structures of the eye. Individuals with leukocytosis have high white blood cell counts, and the excess white blood cells in the blood may cause it to become thicker and have a higher viscosity. This malfunction gives the blood movement a slow or sluggish flow rate through the body due to its friction against the vein and artery walls. This thickened blood flows through the main artery to the head and then may fail to fully infiltrate into the numerous branches of small capillaries that supply the cells of the retina.
The retina is a component of the eye responsible for sensing light and sending nerve impulses that contain visual information through the optic nerve to the brain. When several of these capillaries do not receive blood because of leukocytosis, the affected individual may experience vision issues. These issues include blurry vision, double vision, and blind spots. The thickened blood may also cause other microvascular changes that stop blood from getting to the retinal cells, including hemorrhage or thrombosis.