Opaque cysts of ciliary body were studied in ten myeloma autopsy cases and seven presumed nonmyeloma cases. Two groups were distinguished on basis of gross features of the opaque cysts. Group 1 consisted of six myeloma cases, with numerous large distinctive cysts. The cysts of the second group, comprising the other four myeloma and the seven nonmyeloma cases, were fewer, smaller and more subtle.
The microscopic and histochemical features of the opaque cysts in both groups were indistinguishable. The cysts and the cytoplasm of the mononuclear cells contained within were filled with hyaline, globular, granular, or homogeneous material, histochemically identified as a protein with high carbohydrate content. The cause of the opaque cysts in the myeloma cases was ascribed to the underlying paraprotein disease and a similar occult process was postulated for the other cases.
Foos RY, Allen RA. Opaque Cysts of the Ciliary Body(Pars Ciliaris Retinae). Arch Ophthalmol. 1967;77(4):559-568. doi:10.1001/archopht.1967.00980020561023