Uveal melanomas, often referred to by the media and in the general population as ocular melanomas, may arise from any of the three parts of the uvea, and are sometimes referred to by their location, as choroidal melanoma, ciliary body melanoma, or iris melanoma. Large tumors often encompass multiple parts of the uvea and can be named accordingly. True iris melanomas, originating from within the iris as opposed to originating elsewhere and invading the iris, are distinct in their etiology and prognosis, such that the other tumors are often referred to collectively as Posterior uveal melanomas.

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.

Uveal tumors can originate from melanocytes residing within the iris. Benign melanocytic tumors, such as iris freckles and moles (nevi), are common and pose no health risks, unless they show signs of malignancy, in which case they are classified as iris melanomas. Though derived from uveal melanocytes, iris melanomas share more in common with cutaneous (skin) melanomas, in that they frequently harbor BRAF mutations associated with ultraviolet damage. Iris melanomas are much less likely to metastasize than other uveal melanomas, and less likely to impair vision if detected and treated early. Approximately 5% of uveal melanomas involve the iris.

The most common and obvious sign of retinoblastoma is an abnormal appearance of the retina as viewed through the pupil, the medical term for which is leukocoria, also known as amaurotic cat's eye reflex. Other signs and symptoms include deterioration of vision, a red and irritated eye with glaucoma, and faltering growth or delayed development. Some children with retinoblastoma can develop a squint, commonly referred to as "cross-eyed" or "wall-eyed" (strabismus). Retinoblastoma presents with advanced disease in developing countries and eye enlargement is a common finding.

Depending on the position of the tumors, they may be visible during a simple eye exam using an ophthalmoscope to look through the pupil. A positive diagnosis is usually made only with an examination under anesthetic (). A white eye reflection is not always a positive indication of retinoblastoma and can be caused by light being reflected badly or by other conditions such as Coats' disease.

The presence of the photographic fault red eye in only one eye and not in the other may be a sign of retinoblastoma. A clearer sign is "white eye" or "cat's eye" (leukocoria).

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.

Orbital dermoid cysts are benign which are typically found at the junction of sutures, most commonly at the fronto-zygomatic suture. Large deep orbital dermoid cysts can cause pressure effects on the muscles and optic nerve, leading to diplopia and loss of vision.

The most common eyelid tumor is called basal cell carcinoma. This tumor can grow around the eye but rarely spreads to other parts of the body. Other types of common eyelid cancers include squamous carcinoma, sebaceous carcinoma and malignant melanoma. The most common orbital malignancy is "orbital lymphoma". This tumor can be diagnosed by biopsy with histopathologic and immunohistochemical analysis. Most patients with orbital lymphoma can be offered chemotherapy or radiation therapy.

There are two forms of the disease, a heritable form and non-heritable form (all cancers are considered genetic in that mutations of the genome are required for their development, but this does not imply that they are heritable, or transmitted to offspring). Approximately 55% of children with retinoblastoma have the non-heritable form. If there is no history of the disease within the family, the disease is labeled "sporadic", but this does not necessarily indicate that it is the non-heritable form. Bilateral retinoblastomas are commonly heritable, while unilateral retinoblastomas are commonly non-heritable.

In about two-thirds of cases, only one eye is affected (unilateral retinoblastoma); in the other third, tumors develop in both eyes (bilateral retinoblastoma). The number and size of tumours on each eye may vary. In certain cases, the pineal gland or the suprasellar or parasellar region (or in very rare cases other midline intracranial locations) is also affected (trilateral retinoblastoma). The position, size and quantity of tumours are considered when choosing the type of treatment for the disease.

Intraocular lymphoma is a rare malignant form of eye cancer. Intraocular lymphoma may affect the eye secondarily from a metastasis from a non-ocular tumor or may arise within the eye primarily (primary intraocular lymphoma, PIOL). PIOL is a subset of primary central nervous system lymphoma (PCNSL). PCNSL (and PIOL) are most commonly a diffuse large B-cell immunohistologic subtype of non-Hodgkin's lymphoma according to the World Health Organization (WHO) classification of lymphomas. The most common symptoms of PIOL include blurred or decreased vision due to tumor cells in the vitreous. Most cases of PIOL eventuate to central nervous system involvement (PCNSL) while only 20% of PCNSL lead to intraocular (PIOL) involvement. PIOL and PCNSL remain enigmas because both structures are immunologically privileged sites (the brain sits behind the blood–brain barrier and the retina sits behind the blood-retinal barrier) and so do not normally have immune cells trafficking through these structures. What is more, while the vast majority of PCNSL in patients with acquired immune deficiency syndrome (AIDS) is related to the Epstein-Barr virus (EBV), the development of PCNSL and PIOL in immunocompetent patients is unknown and shows no general relation to infectious DNAs.

In immunocompetent patients, PIOL most commonly affects patients in their fifties and sixties. AIDS patients typically develop the disease earlier in their lives.

PIOL affects the sub-retinal pigment epithelium (RPE), can invade into the retina, the vitreous, and the optic nerve. Ophthalmoscopy frequently reveals creamy yellow-to-orange colored subretinal infiltrates. Fluorescein angiography may reveal "leopard spot" patterns due to sub-RPE infiltrates that stain early and progressively or mottling of the RPE due to hyper- and hypofluorescent window defects.

PIOL is known as a masquerade syndrome because it frequently simulates the signs and symptoms of uveitis. As such, PIOL is frequently treated with corticosteroids. Occasionally, PIOL has mimicked a retinitis and has been treated with antiviral medication. It is not until the supposed uveitis fails to respond to treatment, becomes recalcitrant to treatment, or shows worsening with discontinuation of corticosteroid treatment that another cause is sought out. If PIOL is suspected, it is important to first obtain a magnetic resonance image (MRI) of the brain to rule out cerebral involvement (PCNSL). If MRI is negative, lumbar puncture with cerebrospinal fluid (CSF) cytology should be performed to further rule out CNS disease. Histopathologic identification of atypical lymphocytes is considered the gold standard for diagnosing PCNSL/PIOL. If CSF cytology is negative or inconclusive and PIOL is suspected, a vitrectomy is often performed with cytologic analysis. Furthermore, adjunctive testing including polymerase chain reaction (PCR) amplification to identify monoclonal rearrangements of the immunoglobulin heavy chain (IgH) gene (for B-cell lymphomas) or T-cell receptor (TCR, for the very rare T-cell lymphomas) can be performed.

Previously, radiation therapy was the mainstay treatment for PCNSL/PIOL, but methotrexate has now become first-line.

In most cases, symptoms present themselves at an advanced stage of disease. They can include but are not limited to:

Nosebleed

Nasal obstruction

Proptosis (displacement of the eye)

Vision changes

Headache

Sinonasal undifferentiated carcinoma, abbreviated SNUC, is a rare aggressive type of cancer that arises from epithelium or lining of the nose or sinuses.

Cancer can be considered a very large and exceptionally heterogeneous family of malignant diseases, with squamous cell carcinomas comprising one of the largest subsets.

Conjunctival Squamous Cell Carcinoma (Conjunctival SCC) and corneal intraepithelial neoplasia comprise what are called Ocular Surface Squamous Cell Neoplasias. SCC is the most common malignancy of the conjunctiva in the US, with a yearly incidence of 1-2.8 per 100,000. Risk factors for the disease are exposure to sun (specifically occupational), exposure to UVB, and light-colored skin. Other risk factors include radiation, smoking, HPV, arsenic, and exposure to polycyclic hydrocarbons.

Conjunctival SCC is often asymptomatic at first, but it can present with the presence of a growth, red eye, pain, itching, burning, tearing, sensitivity to light, double vision, and decreased vision.

Spread of conjunctival SCC can occur in 1-21% of cases, with the first site of spread being the regional lymph nodes. Mortality for conjunctival SCC ranges from 0-8%.

Diagnosis is often made by biopsy, as well as CT (in the case of invasive SCC).

Treatment of Conjunctival SCC is usually surgical excision followed by cryotherapy. After this procedure, Conjunctival SCC can recur 8-40% of the time. Radiation treatment, topical Mitomycin C, and removal of the contents of the orbit, or exenteration, are other methods of treatment. Close follow-up is recommended, because the average time to recurrence is 8–22 months.

The most common sites for melanotic tumors are on the under-side of the tail near the base, on the prepuce, around the mouth or in the skin over the parotid gland (near the base of the ear). Tumors will initially begin as single, small raised areas that may multiply or coalesce into multi-lobed masses (a process called melanomatosis) over time. Horses under 2-years-old can be born with or acquire benign melanotic tumors (called melanocytomas), but these tumors are often located on the legs or trunk, not beneath the tail as in older animals.

The appearance and number of sarcoids can vary, with some horses having single or multiple lesions, usually on the head, legs, ventrum and genitalia or around a wound. The distribution pattern suggests that flies are an important factor in the formation of sarcoids. Sarcoids may resemble warts (verrucous form), small nodules (nodular form), oval hairless or scaly plaques (occult form) or very rarely, large ulcerated masses (fibroblastic form). The occult form usually presents on skin around the mouth, eyes or neck, while nodular and verrucous sarcoids are common on the groin, penile sheath or face. Fibroblastic sarcoids have a predilection for the legs, groin, eyelid and sites of previous injury. Multiple forms may also be present on an individual horse (mixed form). Histologically, sarcoids are composed of fibroblasts (collagen producing cells) that invade and proliferate within the dermis and sometimes the subcutaneous tissue but do not readily metastasize to other organs. Surgical biopsy can definitively diagnose sarcoids, but there is a significant risk of making sarcoids worse. Therefore, diagnosis based solely on clinical signs, fine-needle aspiration or complete excisional biopsy are safer choices.

A rhegmatogenous retinal detachment is commonly preceded by a posterior vitreous detachment which gives rise to these symptoms:

- flashes of light (photopsia) – very brief in the extreme peripheral (outside of center) part of vision

- a sudden dramatic increase in the number of floaters

- a ring of floaters or hairs just to the temporal (skull) side of the central vision

Although most posterior vitreous detachments do not progress to retinal detachments, those that do produce the following symptoms:

- a dense shadow that starts in the peripheral vision and slowly progresses towards the central vision

- the impression that a veil or curtain was drawn over the field of vision

- straight lines (scale, edge of the wall, road, etc.) that suddenly appear curved (positive Amsler grid test)

- central visual loss

In the event of an appearance of sudden flashes of light or floaters, an eye doctor needs to be consulted immediately. A shower of floaters or any loss of vision, too, is a medical emergency.

RMS can occur in almost any soft-tissue site in the body; the most common primary sites are genitourinary (24%), parameningeal (16%), extremity (19%), orbit (9%), other head and neck (10%), and miscellaneous other sites (22%). RMS often presents as a mass, but signs and symptoms can vary widely depending on the site of the primary tumor. Genitourinary tumors may present with hematuria, urinary tract obstruction, and/or a scrotal or vaginal mass. Tumors that arise in the retroperitoneum and mediastinum can become quite large before producing signs and symptoms. Parameningeal tumors may present with cranial nerve dysfunction, symptoms of sinusitis, ear discharge, headaches, and facial pain. Orbital tumors often present with orbital swelling and proptosis. Extremity tumors generally present as a rapidly enlarging, firm mass in the relevant tissue. The cancer's prevalence in the head, face, and neck will often allow for earlier signs of the disease simply due to the obvious nature of tumors in these locations. Despite the varying presentation and typically aggressive nature of the disease, RMS has the potential to be diagnosed and treated early. The fourth IRSG study found that 23% of patients were diagnosed in time for a complete resection of their cancer, and 15% had resection with only minimal remnants of the diseased cells.

Eye injury and head trauma may also coincide with a black eye. Some common signs of a more serious injury may include:

- Double vision

- Loss of sight and/or fuzzy vision could occur

- Loss of consciousness

- Inability to move the eye or large swelling around the eye

- Blood or clear fluid from the nose or the ears

- Blood on the surface of the eye itself or cuts on the eye itself

- Persistent headache or migraine

The most common cancers in children are (childhood) leukemia (32%), brain tumors (18%), and lymphomas (11%). In 2005, 4.1 of every 100,000 young people under 20 years of age in the U.S. were diagnosed with leukemia, and 0.8 per 100,000 died from it. The number of new cases was highest among the 1–4 age group, but the number of deaths was highest among the 10–14 age group.

In 2005, 2.9 of every 100,000 people 0–19 years of age were found to have cancer of the brain or central nervous system, and 0.7 per 100,000 died from it. These cancers were found most often in children between 1 and 4 years of age, but the most deaths occurred among those aged 5–9. The main subtypes of brain and central nervous system tumors in children are: astrocytoma, brain stem glioma, craniopharyngioma, desmoplastic infantile ganglioglioma, ependymoma, high-grade glioma, medulloblastoma and atypical teratoid rhabdoid tumor.

Other, less common childhood cancer types are:

- Neuroblastoma (6%, nervous system)

- Wilms tumor (5%, kidney)

- Non-Hodgkin lymphoma (4%, blood)

- Childhood rhabdomyosarcoma (3%, many sites)

- Retinoblastoma (3%, eye)

- Osteosarcoma (3%, bone cancer)

- Ewing sarcoma (1%, many sites)

- Germ cell tumors (5%, many sites)

- Pleuropulmonary blastoma (lung or pleural cavity)

- Hepatoblastoma and hepatocellular carcinoma (liver cancer)

Any abnormality of any one of the three layers of tears produces an unstable tear film, resulting in symptoms of dry eyes.

Typical symptoms of dry eye syndrome are dryness, burning and a sandy-gritty eye irritation that gets worse as the day goes on. Symptoms may also be described as itchy, scratchy, stinging or tired eyes. Other symptoms are pain, redness, a pulling sensation, and pressure behind the eye. There may be a feeling that something, such as a speck of dirt, is in the eye. The resultant damage to the eye surface increases discomfort and sensitivity to bright light. Both eyes usually are affected.

There may also be a stringy discharge from the eyes. Although it may seem strange, dry eye can cause the eyes to water. This can happen because the eyes are irritated. One may experience excessive tearing in the same way as one would if something got into the eye. These reflex tears will not necessarily make the eyes feel better. This is because they are the watery type that are produced in response to injury, irritation, or emotion. They do not have the lubricating qualities necessary to prevent dry eye.

Because blinking coats the eye with tears, symptoms are worsened by activities in which the rate of blinking is reduced due to prolonged use of the eyes. These activities include prolonged reading, computer usage, driving, or watching television. Symptoms increase in windy, dusty or smoky (including cigarette smoke) areas, in dry environments high altitudes including airplanes, on days with low humidity, and in areas where an air conditioner (especially in a car), fan, heater, or even a hair dryer is being used. Symptoms reduce during cool, rainy, or foggy weather and in humid places, such as in the shower.

Most people who have dry eyes experience mild irritation with no long-term effects. However, if the condition is left untreated or becomes severe, it can produce complications that can cause eye damage, resulting in impaired vision or (rarely) in the loss of vision.

Symptom assessment is a key component of dry eye diagnosis – to the extent that many believe dry eye syndrome to be a symptom-based disease. Several questionnaires have been developed to determine a score that would allow for dry eye diagnosis. The McMonnies & Ho dry eye questionnaire is often used in clinical studies of dry eyes.

Retinal detachment is a disorder of the eye in which the retina separates from the layer underneath. Symptoms include an increase in the number of floaters, flashes of light, and worsening of the outer part of the visual field. This may be described as a curtain over part of the field of vision. In about 7% of cases both eyes are affected. Without treatment permanent loss of vision may occur.

The mechanism most commonly involves a break in the retina that then allows the fluid in the eye to get behind the retina. A break in the retina can occur from a posterior vitreous detachment, injury to the eye, or inflammation of the eye. Other risk factors include being short sighted and previous cataract surgery. Retinal detachments also rarely occur due to a choroidal tumor. Diagnosis is by either looking at the back of the eye with an ophthalmoscope or by ultrasound.

In those with a retinal tear, efforts to prevent it becoming a detachment include cryotherapy using a cold probe or photocoagulation using a laser. Treatment of retinal detachment should be carried out in a timely manner. This may include scleral buckling where silicone is sutured to the outside of the eye, pneumatic retinopexy where gas is injected into the eye, or vitrectomy where the vitreous is partly removed and replaced with either gas or oil.

Retinal detachments affect between 0.6 and 1.8 people per 10,000 per year. About 0.3% of people are affected at some point in their life. It is most common in people who are in their 60s or 70s. Males are more often affected than females. The long term outcomes depend on the duration of the detachment and whether the macula was detached. If treated before the macula detaches outcomes are generally good.

Leukocoria (also leukokoria or white pupillary reflex) is an abnormal white reflection from the retina of the eye. Leukocoria resembles eyeshine, but leukocoria can occur in humans and other animals that lack eyeshine because their retina lacks a "tapetum lucidum".

Leukocoria is a medical sign for a number of conditions, including Coats disease, congenital cataract, corneal scarring, melanoma of the ciliary body, Norrie disease, ocular toxocariasis, persistence of the tunica vasculosa lentis (PFV/PHPV), retinoblastoma, and retrolental fibroplasia.

Because of the potentially life-threatening nature of retinoblastoma, a cancer, that condition is usually considered in the evaluation of leukocoria. In some rare cases (1%) the leukocoria is caused by Coats' disease (leaking retinal vessels).

According to the American Academy of Dermatology, the most common types of moles are skin tags, raised moles and flat moles. Benign moles are usually brown, tan, pink or black (especially on dark-colored skin). They are circular or oval and are usually small (commonly between 1–3 mm), though some can be larger than the size of a typical pencil eraser (>5 mm). Some moles produce dark, coarse hair. Common mole hair removal procedures include plucking, cosmetic waxing, electrolysis, threading and cauterization.

Individuals with a basal-cell carcinoma typically present with a shiny, pearly skin nodule. However, superficial basal-cell cancer can present as a red patch similar to eczema. Infiltrative or morpheaform basal-cell cancers can present as a skin thickening or scar tissue – making diagnosis difficult without using tactile sensation and a skin biopsy. It is often difficult to visually distinguish basal-cell cancer from acne scar, actinic elastosis, and recent cryodestruction inflammation.