OF about the market size for beauty salons can often be found from commercial sites that sell reports. damages the eye and slowly leads to blindness. Increased pressure in the eye damages the optic nerve without producing symptoms. Tests can determine if a patient has the disease or at risk for developing glaucoma. Elevated intra-ocular pressures can be the first indication. Changes in the appearance of the optic nerve from increased pressure can warn of the disease. Glaucoma slowly destroys peripheral vision. Automated threshold visual field testing can check for the disease and measure the effectiveness of treatments. The quality of reports varies OF greatly.  OF greatly.