Purpose. Corneal crystalline deposits are a sign of a limited number of conditions that can often be differentiated based
on the appearance and pattern of the deposits. Although, there are limited treatment options available to reduce the
appearance or effects of corneal crystals, it is important to identify the correct etiology of these deposits. There are several
associated systemic conditions, some of which are life threatening, for which treatments are available.
Methods. A 51-year-old black male presented to the clinic with the complaint of “glare at night due to crystals on [the]
cornea.” Slitlamp findings revealed diffuse subepithelial and anterior stromal crystals across both corneas.
Results. The patient had a medical history of renal insufficiency and arthralgia. Through systemic testing, the patient was
found to have monoclonal gammopathy of undetermined significance (MGUS), and subsequent follow-up of this patient
revealed a conversion of MGUS to multiple myeloma.
Conclusions. Corneal crystals can appear diffusely through the cornea secondary to corneal dystrophies, gammopathies,
cystinosis, or other rare systemic conditions. In this case report, these crystals are secondary to MGUS, which progressed
to multiple myeloma. These crystals consist of immunoglobulin, primarily IgG, and excessive kappa light chains. It is
important to obtain laboratory tests and make appropriate referrals to determine whether corneal crystal deposits are
associated with a serious systemic disease or merely a corneal dystrophy.