Early treatment of cancerous melanomas at the back of the eye can help preserve vision as well as save the eye and life itself. However, it is difficult to distinguish small melanomas from benign moles.

Moles at the back of the eye are common and though the vast majority are not harmful, some are difficult to distinguish from small melanomas. This means frequent and long term monitoring is usually required.

Pigmented fundus tumours

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Choroidal nevi

  • Choroidal naevi are benign with a very low risk of malignant transformation
  • The prevalence of choroidal naevi is about six in a 100
  • It is estimated that malignant transformation occurs in less than 1 in 8000 choroidal naevi/​year.
  • Some choroidal melanomas metastasize early, therefore monitoring of choroidal nevi to identify early transformation to melanoma is essential

Choroidal melanoma

  • is a cancer that arises in the choroid, a pigmented layer of tissue under the retina
  • risk factors include: light coloured eyes, fair skin, inability to tan, congenital ocular melanocytosis, the BAP1 tumour predisposition syndrome
  • Sunlight is considered unimportant as most UV light is filtered by the lens of the eye

Multimodal ocular imaging in eye cancer monitoring

The last decade has seen advances in multimodal ocular imaging. Wide-angle colour photography and other kinds of imaging of tumours at the back of the eye, such as fundus autofluorescence imaging and optical coherence tomography, can reveal abnormalities invisible on a conventional eye examination. 

The Covid-19 pandemic has encouraged monitoring to be performed remotely to reduce risk of infection, minimize unnecessary patient travel and maximise NHS resources.

Unlike benign moles, malignant melanomas tend to enlarge over time. Such growth can be measured by ultrasonography. However, this requires skills and equipment not widely available in the community.

Mr. Bertil Damato, consultant ophthalmologist at Moorfields and senior clinical research fellow at the University of Oxford and colleagues reviewed images of 99 patients treated for choroidal melanoma after a period of observation. They found that monitoring for growth can be accomplished safely without the need for ultrasonography by assessing colour photographs alone.

Our findings could help remove barriers to the implementation of tele-oncology clinics for the monitoring of choroidal tumours.

Mr. Bertil Damato, consultant ophthalmologist at Moorfields Eye Hospital

Testing the MOLES system

Mr. Damato has devised an acroynm, MOLES to help non-experts remember the most important signs of malignancy which are:

  • Mushroom tumour shape
  • Orange pigment
  • Large tumour size
  • Enlarging tumour
  • Subretinal fluid

He has also developed a scoring system to estimate the likelihood of malignancy in melanocytic choroidal tumours. Dr. Lamis Al Harby, Professor Mandeep Sagoo and Mr. Damato studied a cohort of 222 patients at Moorfields to test the MOLES system. 

The MOLES system proved highly successful, with the same diagnosis being returned in more than 97% of cases compared with expert diagnosis. This study has received press coverage and will soon be available to read in the journal, Ocular Oncology and Pathology.

Next steps to benefit patients

Further research is needed to evaluate how successfully the MOLES system is used by non-specialist ophthalmologists and community optometrists in a variety of working environments. 

This research promises to improve patient care around the world. It aims to help avoid unnecessary hospital visits while speeding up diagnosis and treatment of those with malignant melanoma. 

These successful results also pave the way for enhancing diagnosis of ocular tumours by artificial intelligence. This is already under way at Moorfields and other centres.

Open access to research findings

The open access of these journal publications are supported by Moorfields Eye Charity Research Enhancement Awards. Open access enables researchers and the public alike to read scientific publications without delay or charge.