Abstract
Purpose :
Choroidal naevi are common and are often referred to secondary services due to the difficulty of differentiating them from small ocular melanoma and the risk of malignant transformation. A common imaging modality used in diagnosis and monitoring of naevi is ultra wide-field imaging. The Optos colour imaging (Optos plc, Dunfermline, Scotland) allows reviewing images in both a ‘red channel’ and ‘green channel’. We investigated whether elevation, a risk factor for malignant transformation, may be detected using these channels.
Methods :
We report on a retrospective observational case-series. Included patients had a choroidal nevomelanocutic lesion with elevation detectable on ultrasound (USS) who also underwent ultra wide-field imaging using the Optos California and 200Tx (Optos plc, Dunfermline, Scotland). A total of 32 patients with lesions detectable on USS were included. A further 25 patients with flat naevi imaged with ultra wide-field served as a control group.
Results :
Mean thickness of elevated choroidal naevi was 1.04mm (+/- 1.08mm). 87.5% of lesions were benign choroidal naevi, 9.4% indeterminate nevomelanocytic lesions and 3.1% presumed melanoma. 37.5% of patients with elevation also had orange pigment. Drusen and sclerosis appeared bright on both red and green channels. When viewed through the red channel all lesions appeared dark. When viewed through the green channel all flat naevi and naevi less than 1mm thick were not visible . However lesionsi with elevation 1mm or greater on USS were visible on the green channel (p=0.0014) showing a bright signal. There is no statistical difference between elevated lesions appearing bright in those with orange pigment and those without orange pigment (p=0.2374).
Conclusions :
Use of the red and green channels on ultra wide-field imaging could offer an easy and accurate way of distinguishing between flat choroidal naevi and those elevated by 1mm or more. This could serve as an effective referral refinement system to identify nevomelanocytic lesions warranting a further USS assessment. This could contribute to alleviating capacity strains on ocular oncology clinics and serve as a reliable screening tool for general ophthalmology practices.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.