They can distinguish between light and dark but no more, enabling them to avoid direct sunlight. In organisms dwelling near deep-sea vents, compound eyes are adapted to see the infra-red light produced by the hot vents; enabling the creatures to avoid being boiled alive. Types
There are ten different eye layouts—indeed every technological method of capturing an optical image commonly used by human beings, with the exceptions of zoom and Fresnel lenses, occur in nature. Eye types can be categorised into "simple eyes", with one concave photoreceptive surface, and "compound eyes", which comprise a number of individual lenses laid out on a convex surface. Note that "simple" does not imply a reduced level of complexity or acuity. Indeed, any eye type can be adapted for almost any behaviour or environment. The only limitations specific to eye types are that of resolution—the physics of compound eyes prevents them from achieving a resolution better than 1°. Also, superposition eyes can achieve greater sensitivity than apposition eyes, so are better suited to dark-dwelling creatures. Eyes also fall into two groups on the basis of their photoreceptors cellular construction, with the photoreceptor cells either being cilliated (as in the vertebrates) or rhabdomeric. These two groups are not monophyletic; the cnidaria also possess cilliated cells,
 and some gastropods, as well as some annelids possess both.Some organisms have photosensitive cells that do nothing but detect whether the surroundings are light or dark, which is sufficient for the entrainment of circadian rhythms.
The FDA granted the approval of Nulibry to Origin Biosciences, Inc., in February 2021. Society and culture
Legal status
On 21 July 2022, the Committee for Medicinal Products for Human Use (CHMP) of the European Medicines Agency (EMA) adopted a positive opinion, recommending the granting of a marketing authorization under exceptional circumstances for the medicinal product Nulibry, intended for the treatment of patients with molybdenum cofactor deficiency (MoCD) Type A. The applicant for this medicinal product is Comharsa Life Sciences Ltd. Fosdenopterin was approved for medical use in the European Union in September 2022. References
External links
"Fosdenopterin". Drug Information Portal. U.S. National Library of Medicine.