It is Sulphonation of Copper. It is generally available in 5H2O (Crystal) form, though anhydrous is also available. Copper sulphate, blue stone, blue vitriol are all common names for pentahydrated cupric sulphate, which is the best known and the most widely used of the copper salts.t is Sulphonation of Copper. It is generally available in 5H2O (Crystal) form, though anhydrous is also available. Copper sulphate, blue stone, blue vitriol are all common names for pentahydrated cupric sulphate, which is the best known and the most widely used of the copper salts.
Disposable soft lenses. Contact lenses were first recognized in 1945 by the American Optometric Association. Over 38 million people wear contacts in the United States alone with international numbers topping 125 million. As more and more people receive proper eye care, the use of contact lenses continues to grow.
If your eye doctor recommends and prescribes disposable bifocal contact lenses, an estimated per-box cost for these lenses is $50 to $70 (similar to the cost of disposable toric contacts). So again, an annual lens cost of $500 to $700 is not unusual if you wear the lenses daily and replace them every two weeks. number of factors can change this estimate, including: Astigmatism. Contact lenses that correct astigmatism cost more than soft contacts that only correct nearsightedness or farsightedness. Soft contact lenses for astigmatism, called toric contacts, frequently retail for $50 to $70 for a box of six lenses.