How Ocular Melanoma Is Diagnosed

Ocular melanoma is sometimes detected during a general eye exam. If it's suspected, your ophthalmologist (eye doctor) will want to take all the steps necessary to diagnose ocular melanoma.

Diagnosis begins with a thorough workup by an ophthalmologist. Tests may follow, including an ultrasound, an imaging test in which sound waves are used, in this case, to depict eye structures.

You may also have fluorescein angiography, in which dye is injected into the bloodstream. Special filters on a camera detect the dye in the eye and can show whether a tumor has damaged structures.

This article will take a closer look at the exam your ophthalmologist will likely perform, the tests you may need to undergo, and the imaging that is often needed. It will also highlight other conditions that may be causing the symptoms you are experiencing.

Physical Examination

While you may have come to the ophthalmologist with complaints such as eye soreness or unexplained vision issues, keep in mind that ocular melanoma may not have any symptoms.

As part of any physical examination looking for signs of ocular melanoma, the ophthalmologist will begin by taking a detailed history. This includes discussing past or current conditions, symptoms you may be having, medications you are taking, and any pertinent family history.

During the exam, the ophthalmologist will expand (dilate) your pupils and examine your eyes with the following:

• Slit lamp: This tool offers views of different structures in the eye with the aid of a light beam and a microscope.
• Gonioscopy: This exam uses a contact lens with mirrors to detect whether a tumor may be blocking fluid from draining from the eye.
• Ophthalmoscope: This instrument contains a microscope and light to look at the back of the eye, including structures such as the optic nerve and light-sensitive retina.

Labs and Tests

In addition to looking directly in the eye, an ophthalmologist or, in some cases, an oncologist (specialist in treating cancer) may call for other types of exams.

A diagnostic test such as an ultrasound exam may be done. This involves moving a probe called a transducer, which transmits high-frequency sound waves, over the eyelid. The sound waves that are echoed back are recorded with the aid of a computer. Signs of a tumor can be detected.

Ocular coherence tomography (OCT) is another type of imaging used. With this, any changes in the reflection of light rays in the eye can be detected, and a cross-sectional retinal image can be constructed. If you have a tiny choroidal melanoma or choroidal nevus (mole), OCT can help locate the tumor.

Fluorescein angiography can also be used to find tumors. Special camera filters can detect the dye injected into the bloodstream when it makes its way to the eye. It can show any damage caused by a tumor in the eye.

If a tumor is detected, you may need a needle biopsy to determine whether it is cancerous or not. This involves numbing the eye, placing a thin hollow needle into the tumor, and extracting a small piece of it. Examination of the sample in the lab can determine the type of tumor and how aggressive it may be.

Differential Diagnosis

In doing a diagnostic workup, the ophthalmologist or oncologist will be trying to distinguish any tumors thought to be ocular melanoma from other conditions that may resemble it.

Here are some conditions—some cancerous, some not—that may have similar signs or symptoms to ocular melanoma:

• Choroidal bleeding, which forms a "blood blister" (an accumulation of blood), may look like ocular melanoma. This condition affects the choroid of the eye (the area between the white sclera and the retina) and is not cancerous.
• Retinal detachment, in which fluid builds up beneath the retina, may be confused with a cancer known as elevated ocular melanoma. Retinal detachment is not a cancerous condition.
• Choroidal hemangioma is a noncancerous vascular (blood vessel) tumor that can lead to retinal detachment and vision problems.
• Choroidal osteoma, in which bone replaces choroidal tissue, can resemble ocular melanoma.
• Orbital lymphoma, a cancerous condition that affects the protective cavity of the eye, is another possibility here.
• Retinoblastoma, a cancer of the light-sensitive retina particularly common in children, can sometimes be mistaken for ocular melanoma.
• Choroidal nevus, a dark pigmented area, is noncancerous but may be at risk of developing into an ocular melanoma in some cases.
• Conjunctival melanoma, a dark spot on the eye's surface that can spread to local tissues, may need to be ruled out.
• Secondary cancer that starts elsewhere and then spreads to the eye may initially be thought to be ocular melanoma.

Summary

Ocular melanoma requires thorough testing. After examining your eye through an expanded pupil, an ophthalmologist may order diagnostic tests. These may include an ultrasound using sound waves, OCT involving light rays, or a fluorescein angiography involving dye and special camera filters.

Your ophthalmologist will consider lookalike conditions, which may include a noncancerous "blood blister." choroidal hemangioma, conjunctival melanoma, or a secondary cancer.

A Word From Verywell

With a condition such as ocular melanoma, it's important that proper testing be done. There is a variety of tests to ensure that you are ultimately correctly diagnosed. You can then be given treatment to best suit your needs and preserve your vision.