Bistructures, bidomains, and linear logic

Improved fluid for intraocular infusion and irrigation and methods of preparation and use. The fluid is an aqueous physiologic saline solution containing from 2-15% by weight of an artificial, substantially non-antigenic oncotic agent of a colloid type, such as dextran having an average molecular weight in the range of from about 1,000 to 40,000. The solution also contains NaCl, CaCl2, dextrose and sodium bicarbonate, and is adjusted to have an osmolarity in the range of 260-400 mOsm/L and a pH in the range of from about 7 to 7.8. The solution may be used as a replacement fluid for the aqueous or vitreous humor, for the reestablishment of intraocular pressure during or after surgery, as an irrigating fluid during phacoemulsification, and generally for external eye surface rinsing during cataract surgery. The solution results in improved lens maintenance and corneal endothelial function during procedures such as vitrectomy, irrigation and aspiration of cataracts, and in phacoemulsification. Improvement is demonstrated, for example, by reduced corneal endothelial decompensation (inhibition of osmotic corneal swelling), by reduced water and sodium gain, by reduced potassium loss, and by recovery of the lens' ability to reverse electrolyte imbalances due to stress of the type typical of surgery, diabetes, ageing, and physical, chemical or biochemical trauma.