Aquatic tetrapods
In many secondarily aquatic vertebrates, the non-bony tissues of the forelimbs and/or hindlimbs are fused into a single flipper. Some remnant of each digit generally remains under the soft tissue of the flipper, though digit reduction gradually occurs such as in baleen whales (mysticeti). Marine mammals evolving flippers represents a classic example of convergent evolution, and by some analyses, parallel evolution.Full webbing of the digits in the manus and/or pes is present in a number of aquatic tetrapods. Such animals include marine mammals (cetaceans, sirenians, and pinnipeds), marine reptiles (modern sea turtles and extinct ichthyosaurs, mosasaurs, plesiosaurs, metriorhynchids), and flightless aquatic birds such as penguins. Hyperphalangy, or an increase in the number of phalanges beyond ancestral mammal and reptile conditions, is present in modern cetaceans and extinct marine reptiles. Schizodactyly
Schizodactyly is a primate term for grasping and clinging with the second and third digit, instead of the thumb and second digit. See also
Artiodactyl – even-toed ungulates, clade Cetartiodactyla
Perissodactyl – odd-toed ungulates

References
External links
Coates, Michael (25 April 2005). "Why do most species have five digits on their hands and feet?". Scientific American. Retrieved 2009-07-05.
Refractive lens exchange (RLE): A variation of cataract surgery where the natural crystalline lens is replaced with an artificial intraocular lens; the difference is the existence of abnormal ocular anatomy which causes a high refractive error. Phakic IOL: Phakic intraocular lens are lenses that implanted inside eye without removing the normal crystalline lens. Phakic IOLs can be used to correct hypermetropia up to +20 diopters.Non laser procedures

Conductive keratoplasty (CK): Conductive keratoplasty is a non laser refractive procedure used to correct presbyopia and low hypermetropia (+0.75D to +3.25D) with or without astigmatism (up to 0.75D). It uses radiofrequency energy to heat and shrink corneal collagen tissue. CK is contraindicated in pregnant/breastfeeding women, central corneal dystrophies and scarring, history of herpetic keratitis, type 1 diabetes etc. Automated lamellar keratoplasty (ALK): Hyperopic automated lamellar keratoplasty (H-ALK) and  Homoplastic ALK are ALK procedures that corrects low to moderate hyperopia. Poor predictability and the risk of complications limits usefulness of these procedures. Keratophakia and epi-keratophakia are another two non laser surgical procedures used to correct hypermetropia. Keratophakia is a surgical technique developed by Barraquer for treating high hypermetropia and aphakia. Poor predictability and induced irregular astigmatism are complications of these procedures. Etymology
The term hyperopia comes from Greek ὑπέρ hyper "over" and ὤψ ōps "sight" (GEN ὠπός ōpos). References


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