Ultra-wide-field imaging of choroidal melanoma before and after proton beam radiation therapy

Abstract

Objective: To evaluate the imaging characteristics of choroidal melanoma before and after proton beam radiotherapy via Optos® ultra-wide-field scanning laser ophthalmoscopy. Methods: Retrospective, descriptive study of choroidal melanoma patients treated with proton beam radiotherapy. All patients underwent full clinical evaluation, including best-corrected visual acuity, ultrasound examination and ultra-wide-field scanning laser ophthalmoscopy imaging in the pseudo-colour (red and green channel) as well as auto-fluorescence mode. Tumours were classified and evaluated according to their location, size, presence of subretinal fluid, drusen, orange pigment and reflectance intensity in ultra-wide-field scanning laser ophthalmoscopy. Tumour sonographic (basal diameter, height) and ultra-wide-field scanning laser ophthalmoscopy imaging dimensions (maximal diameter) were documented. Results: A total of 39 eyes (38 patients) were followed for 24 months (range 6–48 months). Mean best-corrected visual acuity dropped from 20/40 to 20/63 after proton beam radiotherapy. There was no change in the imaging tumour characteristics during follow-up. Subretinal fluid changes were better detected in the autofluorescence compared to pseudo-colour mode. Mean tumour diameter did not significantly change in the ultra-wide-field scanning laser ophthalmoscopy although it did so in the ultrasound. No patient showed local tumour recurrence. Conclusion: The ultra-wide-field scanning laser ophthalmoscopy imaging characteristics of choroidal melanoma in the Optos® system do not significantly change after proton beam radiotherapy after a mean follow-up of 2 years.