Conjunctival melanoma is a rare tumour of the ocular surface with an annual incidence of less than five cases per million and a 10-year mortality of about 30%.1^–5 The standard management of conjunctival melanoma consists of local surgical resection with application of cryotherapy to the margins of resection.3 The regional lymph nodes are thought to be the first site of metastasis for the majority of patients with conjunctival melanoma.1^–5 The reported frequency of regional lymph node metastasis secondary to conjunctival melanoma varies from 20 to 30%, depending on the conjunctival melanoma tumour thickness and other high-risk features such as a palpebral location.1^–5

The traditional ways of assessing the status of regional lymph nodes at the time of initial diagnosis of conjunctival melanoma include palpation of the regional lymph nodes, imaging studies such as computed tomography or magnetic resonance imaging of the regional lymph nodes, and ultrasonography with fine-needle aspiration of suspicious nodes, although admittedly most studies published in the ophthalmic literature do not specify which tests and frequency of administration of these conventional tests are recommended or practised by ocular oncologists who treat conjunctival melanoma. Historically, after surgical removal of the conjunctival melanoma, the regional lymph nodes are clinically observed until overt clinical signs of metastasis develop. Once clinically detectable metastatic disease develops, the prognosis for survival is poor.6

Recently, there has been some progress towards better staging of regional lymph nodes in patients with conjunctival melanoma by adapting sentinel lymph node (SLN) biopsy as a way to discover microscopic (subclinical) metastatic disease.7^–13 There have also been some recent attempts at evaluating positron emission tomography as a way to rule out subclinical metastasis in the regional lymph nodes in patients with conjunctival melanoma.14 Each of …