Acute corneal calcification following chemical injury

To describe the clinical and ultrastructural features of 3 cases of acute corneal calcification following accidental chemical injury.

Three men presented over an 18-month period with unilateral eye injuries sustained when applying an industrial fire retardant. This product is predominantly a gypsum aggregate (calcium sulfate dihydrate) plaster combined under pressure with a set-time accelerator (aluminum sulfate). In each case the tear pH was initially alkaline, and the eyes were irrigated with phosphate-buffered saline according to protocol. Within hours a dense corneal opacity had developed that showed only minor resolution over 3 years of follow-up. Two eyes required corneal graft surgery for visual rehabilitation. Light and electron microscopy and energy dispersive analysis of x-rays (EDAX) was performed on excised tissue.

Light and electron microscopy showed dense mineralization of the anterior stroma with discrete crystalline deposits in the deeper stroma. EDAX of the crystals showed high emission peaks for calcium and phosphorus.

The insolubility, elemental composition, and ultrastructural appearance suggest that the opacity was caused by calcium phosphate deposition. The absence of phosphorus from the listed components of the fire retardant suggests that the use of phosphate-buffered irrigation fluid or the subsequent use of phosphate-buffered drops may have contributed to the deposition of this insoluble crystalline deposit.