pigment in the eyes also results in problems with vision, both related and unrelated to photosensitivity. Those with albinism are generally as healthy as the rest of the population (but see related disorders below), with growth and development occurring as normal, and albinism by itself does not cause mortality, although the lack of pigment blocking ultraviolet radiation increases the risk of melanomas (skin cancers) and other problems. Visual problems Development of the optical system is highly dependent on the presence of melanin. For this reason, the reduction or absence of this pigment in people with albinism may lead to: Misrouting of the retinogeniculate projections, resulting in abnormal decussation (crossing) of optic nerve fibres Photophobia and decreased visual acuity due to light scattering within the eye (ocular straylight) Photophobia is specifically when light enters the eye, unrestrictedwith full force. It is painful and causes extreme sensitivity to light. Reduced visual acuity due to foveal hypoplasia and possibly light-induced retinal damage. Eye conditions common in albinism include: Nystagmus, irregular rapid movement of the eyes back and forth, or in circular motion. Amblyopia, decrease in acuity of one or both eyes due to poor transmission to the brain, often due to other conditions such as strabismus. Optic nerve hypoplasia, underdevelopment of the optic nerve. The improper development of the retinal pigment epithelium (RPE), which in normal eyes absorbs most of the reflected sunlight, further increases glare due to light scattering within the eye. The resulting sensitivity (photophobia) generally leads to discomfort in bright light, but this can be reduced by the use of sunglasses or brimmed hats. Genetics Oculocutaneous albinism is generally the result of the biological inheritance of genetically recessive alleles (genes) passed from both parents of an individual such as OCA1 and OCA2. A mutation in the human TRP-1 gene may result in the deregulation of melanocyte tyrosinase enzymes, a change that is hypothesized to promote brown versus black melanin synthesis, resulting in a third oculocutaneous albinism (OCA) genotype, "OCA3". Some rare forms are inherited from only one parent. There are other genetic mutations which are proven to be associated with albinism. All alterations, however, lead to changes in melanin production in the body. Some of these are associated with increased risk of skin cancer . The chance of offspring with albinism resulting from the pairing of an organism with albinism and one without albinism is low. However, because organisms (including