Ciliary Body Melanoma is a type of cancer arising from the coloured part (uvea) of the eye.

About 12% of uveal melanoma arise from the ciliary body.

The number of cases is around 0.5 to 0.7 per 10,000 births, making it a relatively rare condition.

It occurs most commonly in the sixth decade.

- External signs include dilated episcleral blood vessels ("sentinel vessels"). Extraocular erosion may produce a dark mass beneath the conjunctiva.

- Pressure on the lens by the enlarging tumor can cause astigmatism, sublaxtion of the lens and formation of a localised lens opacity.

- The tumor can erode forward through the iris root and mimic an iris melanoma.

- Retinal detachment can be rarely caused by posterior extension of the tumor.

- Anterior uveitis is an uncommon presentation and occurs due to tumor necrosis.

- Cirumferentially growing tumors carry a bad prognosis as they are diagnosed late.

- At times the tumor is detected as an incidental finding during routine examination.

The tumour is usually diagnosed by clinical examination with a slit-lamp utilising a triple mirror contact lens. Ultrasonography and fine needle aspiration biopsy (FNAB) are also sometimes helpful in confirming the diagnosis.

Colobomas can be associated with a mutation in the "PAX2" gene.

Eye abnormalities have been shown to occur in over 90% of children with fetal alcohol syndrome.

Benign melanocytic tumors of the choroid, such as choroidal freckles and nevi, are very common and pose no health risks, unless they show signs of malignancy, in which case they are considered melanomas. Uveal melanoma is distinct from most skin melanomas associated with ultraviolet exposure; however, it shares several similarities with non-sun-exposed melanomas, such as acral melanomas and mucosal melanomas. BRAF mutations are extremely rare in posterior uveal melanomas; instead, uveal melanomas frequently harbor GNAQ/GNA11 mutations, a trait shared with blue nevi, Nevus of Ota, and Ocular melanosis. As seen in BRAF, mutations in GNAQ/GNA11 are early events in tumorigenesis and are not prognostic for tumor stage or later metastatic spread. In contrast, mutations in the gene BAP1 are strongly linked to metastatic spread and patient survival. Incidence of posterior uveal melanoma is highest among people with light skin and blue eyes. Other risk factors, such as blue light exposure and arc welding have been put forward, but are still debated in the field. Mobile phone use is not a risk factor for uveal melanoma.

The cause of uveal melanoma is unclear. Uveal nevi are common (10% of Caucasians), but rarely progress to melanoma.

Terrier breeds are predisposed to lens luxation, and it is probably inherited in the Sealyham Terrier, Jack Russell Terrier, Wirehaired Fox Terrier, Rat Terrier, Teddy Roosevelt Terrier, Tibetan Terrier, Miniature Bull Terrier, Shar Pei, and Border Collie. The mode of inheritance in the Tibetan Terrier and Shar Pei is likely autosomal recessive. Labrador Retrievers and Australian Cattle Dogs are also predisposed.

Congenital heterochromia is usually inherited as an autosomal dominant trait.

Anisocoria is a common condition, defined by a difference of 0.4 mm or more between the sizes of the pupils of the eyes.

Anisocoria has various causes:

- Physiological anisocoria: About 20% of normal people have a slight difference in pupil size which is known as physiological anisocoria. In this condition, the difference between pupils is usually less than 1 mm.

- Horner's syndrome

- Mechanical anisocoria: Occasionally previous trauma, eye surgery, or inflammation (uveitis, angle closure glaucoma) can lead to adhesions between the iris and the lens.

- Adie tonic pupil: Tonic pupil is usually an isolated benign entity, presenting in young women. It may be associated with loss of deep tendon reflex (Adie's syndrome). Tonic pupil is characterized by delayed dilation of iris especially after near stimulus, segmental iris constriction, and sensitivity of pupil to a weak solution of pilocarpine.

- Oculomotor nerve palsy: Ischemia, intracranial aneurysm, demyelinating diseases (e.g., multiple sclerosis), head trauma, and brain tumors are the most common causes of oculomotor nerve palsy in adults. In ischemic lesions of the oculomotor nerve, pupillary function is usually spared whereas in compressive lesions the pupil is involved.

- Pharmacological agents with anticholinergic or sympathomimetic properties will cause anisocoria, particularly if instilled in one eye. Some examples of pharmacological agents which may affect the pupils include pilocarpine, cocaine, tropicamide, MDMA, dextromethorphan, and ergolines. Alkaloids present in plants of the genera "Brugmansia" and "Datura", such as scopolamine, may also induce anisocoria.

- Migraines

Ocular melanosis (OM), also known as ocular melanocytosis or melanosis oculi, is a congenital disease of the eye which affects about 1 in every 5000 people and is a risk factor for uveal melanoma. In dogs is found almost exclusively in the Cairn Terrier, where until recently it was known as pigmentary glaucoma. The disease is caused by an increase of melanocytes in the iris, choroid, and surrounding structures. Overproduction of pigment by these cells can block the trabecular meshwork through which fluid drains from the eye. The increased fluid in the eye leads to increased pressure, which can lead to glaucoma. In humans, this is sometimes known as pigment dispersion syndrome.

An iris cyst, or uveal cyst, is a small hollow structure either attached to the iris of the eye or floating free in the anterior chamber. An iris cyst is composed of a single cell layer of epithelium and is filled with fluid. It is most commonly seen as secondary to inflammation in the eye, especially with canine glaucoma. They are most commonly seen in dogs. Golden Retrievers, Labrador Retrievers, and Boston Terriers are the most commonly affected breeds. Iris cysts also occur in cats and horses. The cysts are usually free floating in dogs, attached to the pupillary margin in cats, and present in the interior of the iris (especially blue irises) in horses.

Iris cysts usually cause no symptoms, but in large numbers they can cause glaucoma by obstructing the drainage angle of the eye. Golden Retrievers may have a higher rate of glaucoma associated with iris cysts.

Iris cysts need to be differentiated from iris melanoma, a tumor, by demonstrating their hollowness. A light directed at an iris cyst will cause it to transilluminate. Iris cysts can be collapsed if necessary by a veterinarian with a small needle carefully introduced into the anterior chamber. The cysts may also be destroyed by use of a semiconductor diode laser.

In segmental heterochromia, sometimes referred to as sectoral heterochromia, areas of the same iris contains two completely different colors.

Segmental heterochromia is rare in humans; it is estimated that only about 1% of the population have it.

Treatment of glaucoma in iridogoniodysgenesis is primarily surgical.

It is listed as a "rare disease" by the Office of Rare Diseases (ORD). This means that Iridogoniodysgenesis, dominant type, or a subtype of Iridogoniodysgenesis, dominant type, affects less than 200,000 people in the US population.

Anisocoria is a condition characterized by an unequal size of the eyes' pupils. Affecting 20% of the population, it can be an entirely harmless condition or a symptom of more serious medical problems.

Polycoria is a pathological condition of the eye characterized by more than one pupillary opening in the iris. It may be congenital or result from a disease affecting the iris.

Polycoria is extremely rare, and other conditions are frequently mistaken for it.

Lens subluxation is also seen in dogs and is characterized by a partial displacement of the lens. It can be recognized by trembling of the iris (iridodonesis) or lens (phacodonesis) and the presence of an aphakic crescent (an area of the pupil where the lens is absent). Other signs of lens subluxation include mild conjunctival redness, vitreous humour degeneration, prolapse of the vitreous into the anterior chamber, and an increase or decrease of anterior chamber depth. Removal of the lens before it completely luxates into the anterior chamber may prevent secondary glaucoma. A nonsurgical alternative involves the use of a miotic to constrict the pupil and prevent the lens from luxating into the anterior chamber.

According to recent research not a single theory is able to explain the cause fully. However current plausible theories include infection with "Toxoplasma gondii", Herpes simplex virus, Rubella, neurogenic causes, and autoimmune pathology.

Aniridia is the absence of the iris, usually involving both eyes. It can be congenital or caused by a penetrant injury. Isolated aniridia is a congenital disorder which is not limited to a defect in iris development, but is a panocular condition with macular and optic nerve hypoplasia, cataract, and corneal changes. Vision may be severely compromised and the disorder is frequently associated with a number of ocular complications: nystagmus, amblyopia, buphthalmos, and cataract. Aniridia in some individuals occurs as part of a syndrome, such as WAGR syndrome (kidney nephroblastoma (Wilms tumour), genitourinary anomalies and intellectual disability), or Gillespie syndrome (cerebellar ataxia).

Many people of East Asian descent are prone to developing angle closure glaucoma due to shallower anterior chamber depths, with the majority of cases of glaucoma in this population consisting of some form of angle closure. Higher rates of glaucoma have also been reported for Inuit populations, compared to white populations, in Canada and Greenland.

No clear evidence indicates vitamin deficiencies cause glaucoma in humans. It follows, then, that oral vitamin supplementation is not a recommended treatment for glaucoma. Caffeine increases intraocular pressure in those with glaucoma, but does not appear to affect normal individuals.

The AN2 region of the short arm of chromosome 11 (11p13) includes the PAX6 gene (named for its PAired boX status), whose gene product helps regulate a cascade of other genetic processes involved in the development of the eye (as well as other non-ocular structures). This PAX6 gene is around 95% similar to the pax gene found in zebrafish, a creature whose ancestors diverged from human evolutionary development around 400 million years ago. Thus the PAX6 gene is highly conserved across evolutionary lineages.

Defects in the PAX6 gene cause aniridia-like ocular defects in mice (as well as "Drosophila"). Aniridia is a heterozygous disorder, meaning that only one of the two chromosome 11 copies is affected. When both copies are altered (homozygous condition), the result is a uniformly fatal condition with near complete failure of entire eye formation. In 2001, two cases of homozygous aniridia patients were reported; the fetuses died prior to birth and had severe brain damage. In mice, homozygous "small eye" defect (mouse Pax-6) leads to loss of the eyes and nose and the murine fetuses suffer severe brain damage.

Iridogoniodysgenesis, dominant type (type 1, IRID1) refers to a spectrum of diseases characterized by malformations of the irido-corneal angle of the anterior chamber of the eye. Iridogoniodysgenesis is the result of abnormal migration or terminal induction of neural crest cells. These cells lead to formation of most of the anterior segment structures of the eye (corneal stroma & endothelium, iris stroma, trabeculum).

As the name implies, it is the bulge of weak sclera lined by ciliary body, which occurs about 2–3 mm away from the limbus. Its common causes are thinning of sclera following perforating injury, scleritis & absolute glaucoma.

it is part of anterior staphyloma

Fuchs heterochromic iridocyclitis (FHI) is a chronic unilateral uveitis appearing with the triad of heterochromia, predisposition to cataract and glaucoma, and keratitic precipitates on the posterior corneal surface. Patients are often asymptomatic and the disease is often discovered through investigation of the cause of the heterochromia or cataract. Neovascularisation (growth of new abnormal vessels) is possible and any eye surgery, such as cataract surgery, can cause bleeding from the fragile vessels in the atrophic iris causing accumulation of blood in anterior chamber of the eye, also known as hyphema.

It is the name given to the localised bulge in limbal area, lined by the root of the iris. It results due to ectasia of weak scar tissue formed at the limbus, following healing of a perforating injury or a peripheral corneal ulcer. There may be associated secondary angle closure glaucoma, may cause progression of the bulge if not treated. Defective vision occurs due to marked corneal astigmatism. Treatment consists of localised staphylectomy under heavy doses of oral steroids.