Scleral Thinning Documented by Ultrasound Biomicroscopy after Plaque Therapy for Anterior Ciliary Melanoma

PURPOSE: To evaluate, by ultrasound biomicroscopy (UBM), changes in scleral thickness after ruthenium-106 CCB and CCC plaque (Eckert & Ziegler BE-BIG GmbH, Berlin, Germany) therapy for anterior ciliary melanoma. METHODS: Eleven patients with anterior ciliary melanoma underwent ruthenium-106 CCB and CCC plaque radiation with a radiation dose at the tumor apex of 80-100 Gy. UBM measurements performed prior to and after treatment were as follows: the largest prominence of the tumor perpendicular to the sclera and scleral thickness at scleral spur, 1.0 mm, and 2.0 mm posteriorly. RESULTS: The article presents one year follow-up results for each of the 11 patients. The mean regression of the tumor of 24.3±9.31% was observed. The thinning of the sclera was statistically significant at the scleral spur (t=1.80, p ≤ 0.05) and at maximal tumor thickness (t=1.35, P=0.05). CONCLUSION: UBM documented significant thinning of the sclera at the scleral spur and overlying the maximal tumor thickness after Ru-106 CCB and CCC plaque radiation. Taking into consideration the shortcomings of the study-small sample size, insufficient probe resolution, and subjectively determined anatomic landmarks-observed minimal thickness change of the sclera does not necessarily mean its necrosis. However, thinning of the sclera documented at one year follow-up associated with very slow regression of the tumor indicates the need for the introduction of the CIA plaque treatment in our patients with anterior ciliary melanoma.