Bernauer W Thiel MA Langenauer UM Rentsch KM 2006 BACKGROUND Irrigating solutions and eye drops may contain phosphates as part of their buffer system. In the presence of epithelial keratopathy, a high concentration of phosphate favours corneal calcification. Knowledge of the phosphate concentration in artificial tear products helps to prevent this sight-threatening complication. This study gives an overview on the amount of phosphate contained in artificial tears. METHODS Fifty-nine samples of commercially available artificial tear preparations were tested. The quantification of phosphate was performed using the molybdate method on a Modular P autoanalyzer. RESULTS Twenty-six of 59 (44%) artificial tear products had a phosphate concentration above physiological levels (>1.45 mmol/l). A phosphate concentration above 25 mmol/l was found in nine products (15%), a concentration higher than 50 mmol/l in three (5%). CONCLUSIONS Many artificial tear formulations contain unphysiological levels of phosphate, but very high concentrations are found only in a few products. These preparations have the potential to favour the formation of insoluble crystalline calcium phosphate deposits when used on a damaged corneal surface, and should therefore be used cautiously. application/pdf https://sonar.ch/global/documents/57141 eng info:eu-repo/semantics/altIdentifier/doi/10.1007/s00417-005-0219-9 info:eu-repo/semantics/altIdentifier/pmid/16418839 info:eu-repo/semantics/openAccess Graefe's archive for clinical and experimental ophthalmology = Albrecht von Graefes Archiv fur klinische und experimentelle Ophthalmologie. - 2006 Autoanalysis Ophthalmic Solutions Phosphates Phosphate concentration in artificial tears. http://purl.org/coar/resource_type/c_6501