Calcium Oxalate and Calcium Phosphate Crystals in Detached Retinas

Crystals of a characteristic type occur occasionally in detached retinas (and rarely in nuclei of cataractous lenses). To our knowledge, they have been described only once previously (Johnson1). They were then identified by microincineration as calcium oxalate. A passing reference had been made to them in a prior publication (Flocks, Littwin, and Zimmerman2), and examples had been collected for some time in the files of the Armed Forces Institute of Pathology under the tentative heading of "protein crystals." * Our studies, undertaken simultaneously and without knowledge of these other investigations, led by different routes to the conclusion that the crystals were both oxalate and phosphate salts of calcium.† Crystals tentatively identified as calcium oxalate (see Adams, D. R.: Brit. J. Ophth. 14:49, 1930) have been described in retinas of rabbits poisoned with naphthalene. In contrast to the cases described in the present paper, the crystals with naphthalene poisoning are