Osmolality of various viscoelastic substances: Comparative study

Purpose: To determine the osmolality of various viscoelastic substances. Setting: Department of Ophthalmology, Johannes Gutenberg-University, Mainz, and Institute for Medical Device Testing, Memmingen, Germany. Methods: The analysis was carried out according to the European Pharmacopoeia by means of a calibrated osmometer using the freezing-point depression method. Each syringe was analyzed as a duplicate analysis. Results: Mean osmolalities (mOsmol/kg) of the sodium hyaluronate viscoelastic substances were Allervisc(R) 299; Allervisc(R) Plus 307; Amvisc(R) Plus 335; AMO Vitrax(R) 284; Biolon(R) 279; Dispasan(R) 311; Dispasan(R) Plus 314; Healon(R) 295; Healon GV(R) 312; Healon(R)5 322; HYA-Ophtal(R) 376; Microvisc(R) 313, Microvisc(R) Plus 341; Provisc(R) 307; Rayvisc(R) 312; Viscoat(R) 340; Visko(R) 296; Visko(R) Plus 319. Mean osmolarities of the hydroxypropyl methylcellulose viscoeslatic substances were Adatocel(R) 278; HPMC Ophtal(R) L358; HPMC Ophtal(R) H 360; La Gel(R) 317; OcuCoat(R) 309; Visco Shield(R) 376. Conclusion: There were significant differences in osmolality among viscoelastic substances, which may explain the differences in corneal thickness after cataract surgery. A viscoelastic substance with an osmolality of 305 mOsmol/kg or slightly higher is preferable, especially in patients with a compromised corneal endothelium. J Cataract Refract Surg 2000; 26: 1242-1246 (C) 2000 ASCRS and ESCRS.