Vitamin A is a family of fat-soluble vitamins. Retinal is one of the most active, or usable, forms of vitamin A. It plays an important role in vision, bone growth, reproduction, cell division and differentiation. It maintains the surface linings of eye and respiratory, urinary, and intestinal tracts. Vitamin A may help lymphocytes a type of white blood cell that fights infections, function more effectively. It also may help prevent bacteria and viruses from entering body by maintaining the integrity of skin and mucous membranes.

Vitamin B12 is a water-soluble vitamin. It is important to good health. It is also called cobalamin. Water-soluble vitamins dissolve in water. After the body uses these vitamins, leftover amounts leave the body through the urine. Vitamin B12 is special, because the body can store it for years in the liver. Due to this, a vitamin B12 deficience is very rare. It is important for metabolism. It helps in the formation of red blood cells and in the maintenance of the central nervous system.

Vitamin B6 is a water-soluble vitamin that exists in three major chemical forms: pyridoxine, pyridoxal, and pyridoxamine. It performs a wide variety of functions in human body and is essential for good health. It is essential for more than 100 enzymes involved in protein metabolism. It is also needed for red blood cell metabolism.

Vitamin C is also known as ascorbic acid. It is a water-soluble vitamin. It is required for the synthesis of collagen, an important structural component of blood vessels, tendons, ligaments, and bone. Vitamin C also plays an important role in the synthesis of the neurotransmitter and nor epinephrine. Neurotransmitters are critical to brain function and are known to affect mood. In addition, vitamin C is required for the synthesis of carnitine, a small molecule that is essential for the transport of fat to cellular organelles called mitochondria, for conversion to energy. It is also involved in the metabolism of cholesterol to bile acids, which may have implications for blood cholesterol levels and the incidence of gallstones.

Vitamin D is a fat-soluble vitamin, which acts like a hormone, regulating the formation of bone and the absorption of calcium and phosphorus from the intestine. It helps to control the movement of calcium between bone and blood. The term vitamin D also refers to metabolites and other analogues of these substances. It plays an important role in the maintenance of organ systems. It regulates the calcium and phosphorus levels in the blood by promoting their absorption from food in the intestines, and by promoting re-absorption of calcium in the kidneys. It promotes bone formation and mineralization and is essential in the development of an intact and strong skeleton.

Vitamin E is a fat-soluble vitamin that acts as an antioxidant. It is an antioxidant that protects body tissue from damage caused by unstable substances called free radicals. Free radicals can harm cells, tissues, and organs. It is also important in the formation of red blood cells and helps the body to use vitamin K. The ability of vitamin E to prevent cancer, heart disease, dementia, liver disease, and stroke are still not known. At lower levels, vitamin E may help protect the heart.

Vitamin K is a fat-soluble vitamin. It is essential for the functioning of several proteins involved in blood clotting. It is a necessary participant in synthesis of several proteins that mediate both coagulation and anticoagulation. The key vitamin K-dependent proteins include coagulation proteins, anticoagulation proteins, bone proteins osteocalcin and matrix-Gla protein, and certain ribosomal proteins.

Biotin is a water-soluble vitamin. It is generally classified as a B-complex vitamin. It is required by all organisms but can only be synthesized by bacteria, yeasts, molds, algae, and some plant species. In its physiologically active form biotin is attached at the active site of four important enzymes, known as carboxylases. Each carboxylase catalyzes an essential metabolic reaction.

Folate is a water-soluble B vitamin that occurs naturally in food. It helps to produce and maintain new cells. This is especially important during periods of rapid cell division and growth such as infancy and pregnancy. Folate is needed to make DNA and RNA, the building blocks of cells. It also helps prevent changes to DNA that may lead to cancer. Both adults and children need folate to make normal red blood cells and prevent anemia. Folate is also essential for the metabolism of homocysteine, and helps maintain normal levels of this amino acid.

Niacin is a water-soluble vitamin, which is also known as nicotinic acid or vitamin B3. Nicotinamide is the derivative of niacin and used by the body to form the coenzymes nicotinamide adenine dinucleotide (NAD) and nicotinamide adenine dinucleotide phosphate (NADP).

Pantothenic acid is also known as vitamin B5. It is essential to all forms of life. It is found throughout living cells in the form of coenzyme A (CoA), a vital coenzyme in numerous chemical reactions. Pantothenic acid is a component of coenzyme A (CoA), an essential coenzyme in a variety of reactions that sustain life. CoA is required for chemical reactions that generate energy from food, fat, carbohydrates, and proteins.

Riboflavin is a water-soluble B vitamin. It is also known as vitamin B2. In the body, riboflavin is primarily found as an integral component of the coenzymes, flavin adenine dinucleotide (FAD) and flavin mononucleotide (FMN). Coenzymes derived from riboflavin are termed flavocoenzymes, and enzymes that use a flavocoenzyme are called flavoproteins.

Thiamin is a water-soluble B vitamin. It occurs in the human body as free thiamin and as various phosphorylated forms: thiamin monophosphate (TMP), thiamin triphosphate (TTP), and thiamin pyrophosphate (TPP), which is also known as thiamin diphosphate.

Vitamins are organic compounds. It is required in small amounts for essential metabolic reactions in a living organism. The term vitamin does not include other essential nutrients such as dietary minerals, essential fatty acids, or essential amino acids, nor does it encompass the large number of other nutrients that promote health but that are not essential for life. These are bio-molecules that act both as catalysts and substrates in chemical reactions. When acting as a catalyst, vitamins are bound to enzymes and are called cofactors.

Vitreoretinal surgery, Radiation plaque is a device used in eye-sparing treatment for choroidal melanoma. It can be used to deliver a high dose of radiation to an intraocular tumor. It is a small, gold covered, dish-shaped device that contains a radioactive source. It contains rice-sized radiation seeds that emit low energy photons. The gold coat of the plaque helps to aim the radiation photons directly at the tumor and decrease radiation damage to surrounding tissues.

Vitreoretinal surgery, Vitreoretinal illumination system provides the bright, white illumination used for vitreoretinal surgery. It utilizes a metal halide discharge lamp, which is a more efficient source of high quality illumination. This exceptional illumination quality provides a color consistency, which is well suited for vitreoretinal surgery. It has also responded to clinical concerns regarding minimizing the incidence of phototoxicity, especially when surgical conditions dictate working close to the retina.