The appearance of chameleonChameleon-like corneal opacitiesCorneal opacities in monoclonal gammopathiesMonoclonal gammopathies (MG) is not well known in Ophthalmology. Today, the hematologists distinguish between three forms of MG: Multiple Myeloma (MM); Smoldering Multiple Meloma (SMM) and Monoclonal GammopathyMonoclonal gammopathies of Undetermined Significance (MGUSMGUS). MGUSMGUS and SMM are percursors of MM and are asymptomatic disorders from the hematological view. MGUSMGUS is a hidden disorder and one of the most common premalignant disorders in Western countries, with a prevalence of 3.2% in the white general population 50 years of age or older. However, in MGUSMGUS there are many corneal opacitiesCorneal opacities from the ophthalmological view, which can also reduce the visual acuity. The purpose of this chapter was to show four patients with distinct corneal opacitiesDistinct corneal opacities that enabled the hematological diagnosisDiagnosis of MGUSMGUS.