## 4 Discussion
This theory is consistent with our own case series, in which the patient with neovascular glaucoma showed only a residual fibrotic remnant of the choroidal melanoma after radiotherapy. Neovascular glaucoma was characterized by a noticeable neovascularization of the iris and the ciliary body, and at the histological examination appeared as copious congested end ectatic vessels. Under MRI the angiogenic process manifested in the form of a considerable enhancement of the ciliary body (and the anterior portion of the choroid) on fat-suppressed T1-weighted images obtained after contrast agent administration. Cataracts are another complication ascribable to radiotherapy, affecting about 33% of patients treated with proton beam radiotherapy. The physical properties of protons allow for the sparing of healthy tissues located both on the sides of and behind the lesion; however, the amount of radiation at the entrance of the beam can be comparatively high, thereby promoting the development of a cataract [37]. In their series [PERSON] et al. described a dense cataract in one patient. In this case, at the histological examination, the lens cortex displayed vacuolation, fragmentation of fibers, and development of globules [25]. In our series one patient experienced a cataract; in this case, under MR imaging, the involved lens demonstrated a peripheral hyperintense rim on T1-weighted sequences. This particular appearance somehow resembles cortical laminar necrosis, a pathological phenomenon associated with hypoxia, status epileptic, infections, metabolic diseases, and drug intoxication. Cortical laminar necrosis is characterized by a high signal intensity on T1-weighted sequences, with gyral distribution at the level of cortical brain lesions; gyriform T1 hyperintensity is related to the storage of necrotic debris and denatured proteins [40; 41; 42]. Similarly, it is conceivable that the hyperintense T1 signal we observed in the peripheral portion of the lens may be the result of radiation-induced damage to the proteins of the cortical fibers and the accumulation of debris in the subcapsular region of the lens [28]. In previous articles, some authors reported a noticeable impediment during enucleation because of the dense fibrotic adhesions resulting from radiotherapy [22; 43]. In our series, we observed similar findings in one patient who underwent secondary enucleation three years after proton beam radiotherapy because of local recurrence of a choroidal melanoma. The histologic examination showed the thickening of the sclera in close proximity to the insertion of the superior rectus muscle, in correspondence to the tantalum clips used to delimit the tumor borders before proton beam treatment. Under MR imaging the soft tissue thickening along the outer edge of the sclera was better visible on T2-weighted images, in which fibrotic alteration appeared hypointense because of collagen fiber deposition. To our knowledge, to date, ours is the first study making a radiologic-pathologic correlation of MR findings and histopathologic data of uveal melanomas treated with proton beam radiotherapy undergoing secondary enucleation. To elucidate the MR appearance of alterations induced by radiotherapy on neoplastic and healthy ocular tissues has twofold relevance, since it helps us to understand the pathological basis of the effects of radiation, and also enhances the radiologist's diagnostic confidence in the evaluation of follow-up MR examinations of patients with uveal melanoma. Indeed, during the last few years radiologists have acquired an increasingly important role in the multidisciplinary approach to patients with uveal melanoma. Although the detection of radiotherapy-related complications is not the primary aim of MR imaging, the thorough assessment of the effects of radiotherapy on both neoplastic and ocular tissue, and the confirmation of the clinical findings of the MR examination, may be crucial in patients' multidisciplinary management and, in particular, in choosing whether or not to perform enucleation.