<prompt> Intractable secondary glaucoma is seen inDiffuse iris melanomaNodular iris melanomaMelanocytic deposits in anterior part of irisMelanocyte proliferation in posterior uveal tissue  <response>: Iris melanomas may be of two types :-Circumscribed Nodular: - It is the most common type which presents as a pigmented spot on the iris. Glaucoma is less common and usually treatable.Diffuse iris melanoma: - Present as a unilateral dark iris hyperchromic hetrochromia. The tumor has diffusely infiltration pattern of growth and invades the intertrabecular spaces, and plugs the drainage mechanism. This results in intractable secondary glaucoma. 