Macular Choroidal Thickness in Uveal Melanoma Patients treated with Plaque Radiotherapy

Abstract

Purpose: To evaluate the macular choroidal thickness in uveal melanoma patients following plaque radiotherapy

Methods: Macula of both eyes of eleven uveal melanoma patients who were treated with plaque radiotherapy were scanned by using enhanced depth imaging feature of Heidelberg Spectralis HRA+OCT (Heidelberg Engineering, Heidelberg, Germany). A cross-section of the retina and choroid was identified for each patient. The choroid was identified as the area between Bruch’s membrane and the anterior scleral border, which were manually identified using ImageJ (v.145s, NIH). A choroidal area was measured for a 3000 micron-wide section of the choroid and centered on the fovea for both eyes of every patient. For each patient, choroidal areas were compared between their plaque-treated and untreated control eye. All patients underwent complete eye examination to assess radiation retinopathy and maculopathy without knowing the result of OCT-EDI.

Results: The mean time interval following plaque radiotherapy was 50 months (range: 12mo-121mo). Seven of 11 patients exhibited clinical findings of radiation maculopathy and retinopathy in their plaque-treated eye. In all patients, the average difference in macular choroidal area between plaque-treated and untreated eyes was 35000μm² vs 41000μm², respectively (p = 0.06). A priori subgroup analysis of 7 patients with radiation retinopathy showed a similar trend towards decreased choroidal thickness in plaque-treated eyes (38000μm² vs 33000μm², p=0.17). The decrease choroidal area eyes corresponds to, on average, a 15% reduction in choroidal thickness in plaque-treated eyes regardless of whether clinical radiation retinopathy was present.

Conclusions: A trend towards decreased choroidal thickness in eyes with a history of plaque-radiotherapy was observed. Further investigations are warranted into the effect of plaque-radiotherapy on choroidal structure and function.

Keywords: 671 radiation therapy • 452 choroid • 552 imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound)