Eye cancer is the disease that results from uncontrolled (abnormal) growth of cells in the eye. Just like any other part of the body, cells in the eye can start to grow out of control due to various reasons and develop into cancer.
About the Eye
An eye is a sensory organ responsible for collecting light and sending it to the brain to form images. The eye has three main parts which are as follows;
> Eye ball: sometimes this is called the globe. Eye ball is formed by major three parts also called layers.
> Uvea: This is the middle part(layer) of the eye ball which consist of the following.
> Iris:This is the coloured part of the eye which surrounds the pupil. Like diaphragm of the camera iris controls amount of light reaching the back side of the eye by adjusting the size of pupil (small opening through which light enters the eye)
> Ciliary body:.This part of uvea is formed by muscles that are responsible for adjusting lens of the eye so as to focus on near and distant object. > Choroid: Choroid is the part of the eye ball containing cells called melanocytes from which melanoma of the eye originate.
> Retina: This is the part of the eye where light rays collect to form image. This part contains light sensitive cells that that form nerves called optic nerves that carry image formed in retina to the brain for interpretation.
Cancers that start in the eye ball are also called intraocular cancers which means they originate within the eye.
Cancers that start in the eye ball are also called intraocular cancers which means they originate within the eye.
Orbit (eye socket): Orbit can simply be defined as cavity in the skull that encloses eyeball with its surrounding muscles. Cancers that start from this part of the eye are called orbital cancers.
Adnexal structures: These are also called accessory structures of the eye. These include structures like tear glands and eyelids. Also cancers affecting these parts are called adnexal cancers.
In this page, the focus will be more on cancers that start in the eye ball which are called intraocular cancers. Orbital and adnexal cancers will be explained more on other pages.
Types of intraocular cancers
Mainly there are two types of intraocular cancers. These include, primary and secondary intraocular cancers:-
Primary intraocular cancers- These are the ones that originate in the eye directly. In this type there are also cancers of different kinds depending on the cells involved in development of that cancer.
• Melanoma: Melanoma is the cancer that originate from pigment making cells called melanocytes. This type of cancer is more common in adults. Melanoma of the eye commonly develop in the uvea which makes it to be called uveal melanoma.
• Lymphoma: lymphoma are the cancers that originate from cells called lymphocytes. Generally there are two types of lymphoma, Hodgkin and Non Hodgkin lymphoma. But in the eye Non Hodgkin is more common.
• Retinoblastoma: Retinoblastoma is the eye cancer that is more common to children than adults. This cancer originate from cells in the retina.
• Medulloepithelioma: This is a very rare type of intraocular cancer which is more common to children than adults.
Secondary intraocular cancers- These are the cancers that start in another part of the body and spread to the eye. These cancer are not really eye cancers as they don`t originate there. Most of secondary eye cancers originate from breast (breast cancer) and lungs (lung cancer).
Risk factors of eye (intraocular) cancers
When it comes to cancer, anything that increases your probability of developing cancer is called a risk factor. Risk factors only influence development of cancer but it does not directly cause cancer. Sometimes people with risk factors do not develop the disease while those with no risk factors do develop the disease. Knowing risk factors will help you live your life making some better healthy choices to reduce the risk. Below are some of the risk factors of eye cancer.
• Age:- Although eye cancer develops to both adults and children, there are those that are more common to children like retinoblastoma and other kinds of eye cancer that are more common to adults.
• Race:- Statistics shows that, white people are at more risk compared to black people.
• Eye color. People with light colored iris are more prone to eye cancer compared to those with brown colored iris.
• Family history. Those with the family history of having disease like uveal nevus, congenital ocular melanocytosis (having abnormal brown spot in their eyes) and dysplastic nevus syndrome (having abnormal spots on their skin) are at higher risk of developing eye cancer than others.
• Compromised immune system. People with compromised immune system are said to be at increased risk of developing lymphomas of different parts of the body, including lymphoma of the eye. For example those with AIDS.
• Sunlight. Although it is still unproven, some link melanoma of the eye and that of skin. Since skin melanoma can be caused by the effect of sun light, then melanoma of the eye has also been linked by that fact.
Prevention of eye cancer
In order to prevent something you need first to know what causes it. When it comes to eye cancers, the exact cause of this cancer is not known so it is difficult to prevent development of this disease.
From the risk factors above, the risk of developing eye cancer can be reduced by reducing your exposure to sun light. Wearing UV-protected sunglasses it is also recommended when you are in strong sun light.
Also since compromised immunity increases your chance of developing lymphoma of the eye, then maintaining life style that strengthens your immunity is very important in order to reduce the risk of developing lymphoma. For stance, taking healthy meals and doing physical exercises.
Early detection and screening
Screening is the process of running some tests to those with no symptoms with the purpose of testing for diseases like cancer and others. For eye cancer there is no widely recommended screening tests for those at an average risk.
For those with certain health conditions that makes them at higher risk of developing eye cancer, like those with congenital ocular melanocytosis and dysplastic nevus syndrome are advised to attend eye exams more often depending on the advice from their doctors.
Eye cancers that are detected at an early stage, are detected through regular eye examinations.
Signs and symptoms of eye cancer
Normally symptoms of eye cancer do not appear at an early stage of the disease so the only way many come to know that they have eye cancer while the disease is still at an early stage is through routine checkup. The following are some of the common signs and symptoms of eye cancer.
• Blurred vision. Their vision start to become unclear.
• Painless and progressive loss of vision field. Eye cancer can cause you to start losing part of your sight field.
• Partial or total loss of vision.
• Floaters. Although sometimes floaters (spots or squiggles drifting in field of vision) occur due to age, but people with eye cancer can also experience this.
• Dark spot which is growing (getting bigger) in your eyes
For advanced eye cancer cases, in addition to the above symptoms and signs, you may also experience the following;
• Weight loss
• Severe ocular pain (eye pain)
• Bulging of the eye
• Changing the position and the way your eye moves within the socket (orbit)
Diagnosis of eye cancer Staging
Doctors use tests to know if you have cancer or not. This process is called diagnosis. During diagnosis doctors test if you have cancer or not and if you have cancer, has it spread to other areas from the original site where tumor originated or not. When it comes to eye cancer, the following are the diagnostic procedures (tests) that can be performed.
In staging of gallbladder cancer, TNM staging system is used. TNM is the combination of tumor; node and metastasis meaning it include assessment of tumor size, nodes involved and its metastasis as described below.
• Eye examination. This is done by an eye specialist known as ophthalmologist. Most cases of eye cancer (melanoma of the eye) are found during a regular eye examination. During eye examination ophthalmologist will ask you if you are having any symptoms. Also will assess your eye movements.
The specialist may use some instruments during this procedure. Those instruments include ophthalmoscope (hand held microscope with a light attached to it).
• Ultrasound. Ultrasound of the eye is one of the most important imaging test used in diagnosis of eye cancer. In some cases this is also used as confirmatory test of eye cancer. The test can show location and size of tumor.
• Fluorescein angiography. This test uses special orange fluorescent dye (fluorescein) which is injected in veins. Pictures of the back of the eye are taken by using a special light that makes fluorescein grow. Although this test doesn`t exactly used to show presence of tumor in the eye, but it can show if there is any other problem with the eye hence doctors will be able to know if the problem of your eye is caused by cancer or something else.
• MRI scan. Magnetic resonance imaging is also important test that is done to those with eye cancer with the intention of checking if cancer has spread to other sites of the body. For example to the brain, lymph nodes and lungs.
• CT scan. Computed tomography scan is also a test that is used to show if the disease has spread to other parts of the body.
• Blood test. This test is not used so as to diagnose eye cancer, but it is done to verify other things like liver function as eye cancer has ability of spread to the liver. So through blood test, doctors will be able to see if your liver is working normally or not.
Treatment of eye cancer
Following cancer diagnosis, the doctor will break the news and it is normally not very easy to accept that it is cancer. The doctor will be there to help the patient process the news and to help the patient in taking the next steps.
After the patient receives and processes the news that he/she has cancer, one of the most important steps that will follow is decision making. The doctor will present to the patient (relatives/parents/guardians) with all the possible treatment options and explain what they mean. Then with the help of the doctor, the patient (relatives/parents/guardian) will have to choose which treatment option is good depending on benefits of such option.
Despite all the information given by the doctor, sometimes the patient may still be unsatisfied with what he/she has been told. In such situation, the patient is free and advised to seek a second opinion. Second opinion is the opinion that the patient may seek from another specialist (doctor) regarding his/her health problem and in this case it is cancer. Second opinion may include confirmation of the diagnosis, more clarification on your primary doctor recommendations or even reassurances that all the options have been explored.
In addition to standard care treatment options, sometimes there are those new treatments or drugs or combination of treatments that have not been approved yet to be used as standard care treatments for a particular cancer (disease) but have shown some promising results that they may help. These type of treatments are called clinical trials.
If there are some clinical trials for your case, the doctor may present to the patient or the patient may ask if there are any clinical trials for the particular cancer case. Over the years, have improved treatments and led to better outcomes to people diagnosed with various diseases including cancer. If you have decided to take part in clinical trial, you can also withdraw at any time.
An eye is one of the sensory organs, so even its treatment is a very delicate procedure. One of the things that your cancer care team will always have in mind when dealing with your case is to try everything to preserve your eye.
When it becomes impossible to preserve it due to various reasons like the disease being too advanced, is when they will find a way to minimize possible side effect from your treatment option. The following are some of the treatment options available for eye cancer;
• Radiation therapy
Surgery is the removal of tumor and surrounding healthy tissues by an operation. This treatment option is performed by a specialized doctor known as surgical oncologist. There are different kinds of surgery that can be done for eye cancer depending on the stage of the disease. These surgical options include,
• Iridectomy. This involves removing part of iris. It is preferred for very small iris melanoma cases.
• Iridocyclectomy. This involves removing part of iris and ciliary body.
• Enucleation. This involves removing the entire eye. This is when the disease is very advanced or the eye lost its ability to see even before treatment.
Side effects of eye cancer surgery
Side effects of eye cancer surgery will depend on the type of surgery performed. Some of the common and possible side effects include the following;
• Possible risk of infection. This can be managed by medications.
• Pain. This can sometimes be relieved with medications
• General problems from anesthesia. If problems are very serious doctors will find a way to relieve them.
• Total removal of an eye will cost your ability to see and affect your appearance which can be fixed by replacing it with an artificial eye
Radiation therapy is an option that involves using high energy x-rays or other radiation particles to destroy cancer cells. Radiation therapy can be delivered in mainly two ways,
• External beam radiation therapy: when radiation beam is directed from the machine outside the body to the treatment (tumor) site.
• Brachytherapy: when radiation sources are placed inside the body (internal radiation therapy)
For eye cancers, brachytherapy is more preferred especially when dealing with melanoma of the eye. In this pellets are placed inside special carriers which are placed in the eye by ophthalmologist. These carriers are made of gold or lead that will help to shield other nearby tissues from being exposed to radiation ensuring maximum radiation is directed towards the tumor.
External beam radiotherapy is mostly preferred to lymphoma of the eye and very few other cases of melanoma of the eye. In this type of treatment, photon beam therapy is the best option. Photon beam therapy uses photons and not x-ray beam. Unlike x-ray beam that release energy before and after the beam hit the target, photon beam causes little damage as the beam releases energy after passing through and traveling some distance.
Side effects of radiation therapyThe side effects of radiation therapy will vary depending on the dose given. Some of the possible side effects include the following;
• Cataract: eye cataract is the condition where a person lens becomes cloudy there by affecting vision ability. These people have trouble of seeing at night. If the problem becomes more serious, it may be resolved surgically.
• Dry eye. This is commonly occur to those who undergo external radiotherapy.
Chemotherapy is the use of special drugs to kill cancer cells. This type of treatment is given by a specialized doctor known as medical oncologist. Generally chemotherapy is can be given through injection into vein (intravenously) by using a needle or given as a pill or capsule that is swallowed (orally). Chemotherapy can sometimes be given in combination with radiation therapy. For eye cancers chemotherapy is mostly used to those with lymphoma of the eye.
Side effectsSide effects of chemotherapy depend on the dose given, type of drug used and periodic time by which it has been used. Most of those side effects will stop after completion of treatment while some of them can be relieved by medication if they become serious during and after treatment course. Some of the possible side effects include the following;
• Hair loss
• Loss of appetite
• Nausea and vomiting