Age Age is the most common cause of<unk> s. Lens proteins denature and degrade over time, and this process is accelerated by diseases such as diabetes mellitus and hypertension. Environmental factors, including toxins, radiation, and ultraviolet light have cumulative effects which are worsened by the loss of protective and restorative mechanisms due to alterations in gene expression and chemical processes within the eye. Trauma Post traumatic rosette<unk>  of a 60-year-old male Blunt trauma causes swelling, thickening, and whitening of the lens fibers. While the swelling normally resolves with time, the white color may remain. In severe blunt trauma, or in injuries that penetrate the eye, the capsule in which the lens sits can be damaged. This damage allows fluid from other parts of the eye to rapidly enter the lens leading to swelling and then whitening, obstructing light from reaching the retina at the back of the eye.<unk> s may develop in 0.7 to 8.0% of cases following electrical injuries. Blunt trauma can also result in star- (stellate) or petal-shaped<unk> s. Radiation<unk> s can arise as an effect of exposure to various types of radiation. X-rays, one form of ionizing radiation, may damage the DNA of lens cells. Ultraviolet light, specifically UVB, has also been shown to cause<unk> s, and some evidence indicates sunglasses worn at an early age can slow its development in later life. Microwaves, a type of nonionizing radiation, may cause harm by denaturing protective enzymes (e.g., glutathione peroxidase), by oxidizing protein thiol groups (causing protein aggregation), or by damaging lens cells via thermoelastic expansion. The protein coagulation caused by electric and heat injuries whitens the lens. This same process is what makes the clear albumen of an egg become white and opaque during cooking. Genetics Christmas tree<unk>  (Diffuse illumination) The genetic component is strong in the development of<unk> s, most commonly through mechanisms that protect and maintain the lens. The presence of<unk> s in childhood or early life can occasionally be due to a particular syndrome. Examples of chromosome abnormalities associated with<unk> s include 1q21.1 deletion syndrome, cri-du-chat syndrome, Down syndrome, Patau's syndrome, trisomy 18 (Edward's syndrome), and Turner's syndrome, and in the case of neurofibromatosis type 2, juvenile<unk>  on one or both sides may be noted. Examples of single-gene disorder include Alport's syndrome, Conradi's syndrome, cerebrotendineous xanthomatosis, myotonic dystrophy, and oculocerebrorenal syndrome or Lowe syndrome. Skin diseases The skin and the lens have the same embryological origin and so can be affected by similar diseases. Those with atopic dermatitis and eczema occasionally develop shield ulcer<unk> s. Ichthyosis is an autosomal recessive disorder associated with cuneiform<unk> s and nuclear sclerosis. Basal-cell nevus and pemphigus have similar associations. Smoking and alcohol Cigarette smoking has been shown to double the rate of nuclear sclerotic<unk> s and triple the rate of posterior subcapsular<unk> s. Evidence is conflicting over the effect of alcohol. Some surveys have shown a link, but others which followed people over longer terms have not. Inadequate vitamin C Low vitamin C intake and serum levels have been associated with greater<unk>  rates. However, use of supplements of vitamin C has not demonstrated benefit. Medications Some medications, such as systemic, topical, or inhaled corticosteroids, may increase the risk of<unk>  development. Corticosteroids most commonly cause posterior subcapsular<unk> s. People with schizophrenia often have risk factors for lens opacities (such as diabetes, hypertension, and poor nutrition) but antipsychotic medications are unlikely to contribute to<unk>  formation. Miotics and triparanol may increase the risk. Post-operative Nearly every person who undergoes a vitrectomy—without ever having had<unk>  surgery—will experience progression of nuclear sclerosis after the operation. This may be because the native vitreous humor is different from the solutions used to replace the vitreous (vitreous substitutes), such as BSS Plus. This may also be because the native vitreous humour contains ascorbic acid which helps neutralize oxidative damage to the lens and because conventional vitreous substitutes do not contain ascorbic acid. Accordingly, for phakic patients requiring a vitrectomy it is becoming increasingly common for ophthalmologists to offer the vitrectomy combined with prophylactic<unk>  surgery to prevent<unk>  formation. Other diseases *Metabolic and nutritional diseases *Aminoaciduria or Lowe's syndrome *Cerebrotendineous xanthomatosis *Diabetes mellitus *Fabry's disease *Galactosemia / galactosemic<unk>  *Homocystinuria *Hyperparathyroidism *Hypoparathyroidism *Hypervitaminosis D *Hypothyroidism *Hypocalcaemia *Mucopolysaccharidoses *Wilson's disease *Congenital *Congenital syphilis *Cytomegalic inclusion disease *Rubella *Cockayne syndrome *Genetic syndromes *Down syndrome *Patau syndrome *Edwards syndrome *Infections: *Cysticercosis *Leprosy *Onchocerciasis *Toxoplasmosis *Varicella *Secondary to other eye diseases: *Retinopathy of prematurity *Aniridia *Uveitis *Retinal detachment *Retinitis pigmentosa Sunflower<unk>  of a forty-year-old male with Wilson's disease and decompensated chronic liver disease
Cataract
Ocular hypertension
Glaucoma
Refractive error
Vitreoretinopathy
Oculomotor nerve palsy
Auditory neuropathy
Aberrations of the eye