Eye mole or choroidal naevus: What does it mean and when should it be checked?
Being told that you have a mole at the back of the eye can understandably sound worrying. In most cases, however, these pigmented lesions are benign and cause no symptoms.
Patients often hear terms such as retinal mole, eye mole or eye freckle. Clinically, many of these lesions are actually located in the choroid, the pigmented and vascular layer beneath the retina, and are known as a choroidal naevus. A choroidal naevus is similar in principle to a mole or freckle on the skin. The difference is that it sits inside the eye and can only be seen during a retinal examination.
Are eye moles dangerous?
Most choroidal naevi are harmless and remain stable throughout life. They are often discovered by chance during a routine eye examination or retinal photograph, and many patients will have had the lesion for years without knowing that it was there.
The reason eye moles are assessed carefully is that, in a small number of cases, a more significant pigmented lesion can have a similar appearance. The aim is therefore not to assume that every eye mole is dangerous, but to establish whether the lesion has reassuring features and whether it has remained stable over time.
Why baseline retinal imaging matters
One of the most useful things that can be done when an eye mole is first identified is to create a high-quality photographic record.
A baseline retinal image provides an objective record of the lesion’s appearance, including its size, shape, pigmentation, position and relationship to nearby retinal structures.
This becomes particularly valuable at future examinations. If another image is taken months or years later, the two can be compared directly to establish whether the lesion has remained unchanged.
A newly photographed eye mole is not necessarily a newly developed eye mole. In many cases, it may simply be the first time that the lesion has been documented properly.
How is a retinal mole assessed?
A retinal or choroidal lesion should not be assessed from a photograph alone. A detailed assessment normally includes a dilated retinal examination, allowing the retina and choroid to be examined more completely. Modern retinal imaging can then provide additional information.
Optos ultra-widefield retinal imaging can capture a very large area of the retina in a single image. This can be particularly useful when a pigmented lesion lies away from the central retina, where conventional photography may be more limited.
OCT imaging, or optical coherence tomography, provides detailed cross-sectional images of the retina. Where the position of the lesion allows, OCT can help assess the retina overlying the naevus and identify subtle changes such as fluid or disruption of the retinal layers.
The important point is that no single scan should be interpreted in isolation. Clinical examination, retinal photography, OCT findings, symptoms and previous images all contribute to the overall assessment.
Do retinal moles cause symptoms?
Most choroidal naevi cause no symptoms at all. They are commonly discovered during an examination being performed for an entirely different reason. Occasionally, a lesion may affect vision if it is close to the macula or associated with changes in the surrounding retina.
Patients should seek assessment if they develop new blurred or distorted vision, flashes of light, a sudden increase in floaters, a shadow in the vision or an unexplained reduction in sight. These symptoms are much more commonly caused by other eye conditions, but they should still be investigated appropriately.
Does every eye mole need hospital oncology referral?
No. Many typical choroidal naevi can be monitored safely using retinal examination and high-quality imaging. Where a lesion appears unusual, shows evidence of change, cannot be assessed adequately or requires additional investigations, onward referral to a specialist ocular-oncology service may be appropriate.
The purpose of a specialist retinal mole assessment is therefore to determine whether the lesion appears reassuring, whether monitoring is appropriate or whether further investigation is required.
Introducing the Birmingham Eye Mole Clinic
The Birmingham Eye Mole Clinic has now been established at Edgbaston Eye Clinic to provide dedicated assessment and monitoring of retinal moles, choroidal naevi and other pigmented retinal lesions. The service combines specialist dilated retinal examination with advanced retinal imaging, including Optos ultra-widefield imaging and Heidelberg SPECTRALIS OCT where clinically appropriate.
High-quality baseline documentation allows lesions to be recorded accurately and compared with previous or future images, while any features requiring further investigation can be identified and referred through the appropriate ophthalmic pathway.
The clinic is based at Edgbaston Eye Clinic, The Consulting Rooms, 38 Harborne Road, Edgbaston, Birmingham, B15 3HE, and is led by Mr Don Williams FCOptom, Advanced Clinical Practitioner (Ophthalmology).
If you have recently been told that you have an eye mole, retinal mole, choroidal naevus or pigmented retinal lesion, or if you would like a specialist second opinion or baseline retinal assessment, a detailed examination can often provide reassurance and establish whether future monitoring is required.
