Midwest Optical Systems

Grayhill is a leading designer and manufacturer of DIP, tact, pushbutton, rotary and encoder switches, keyboards, keypads and front panels, I/O modules, control systems, and wireless products. The privately held firm was started in 1943 to manufacture miniature precision components for the electronics industry. The company produces high quality components for commercial, industrial and military markets. In addition to engineering and manufacturing, Grayhill sells internationally through independent local manufacturers' representatives and a network of local, regional, and national stocking component distributors for switch products and industrial distributors for industrial control products. The company employs 600 people in its four worldwide locations LaGrange and Carpentersville, Ill., Iola, Wis., and Shenzhen, China.

Pro-Optics Inc in Palatine is a trusted provider of high-quality optical accessories and ophthalmic consumables, all proudly manufactured in the USA. Their value-priced products cater to the needs of professionals in the optical industry. With a commitment to excellence, Pro-Optics Inc ensures that their range of products meets the highest standards while offering competitive pricing. Customers can rely on their dedication to delivering top-notch optical solutions. Generated from their website's infomation

For nearly forty years Precision Vision has built a reputation of producing the most accurate and most durable vision testing tools available. Earning trust and confidence we have worked closely with some of the greatest contributors to the eye care profession creating high quality charts and other devices by combining ideas, expertise and high standards. Doctors, researchers and practitioners around the world depend on our commitment to quality. In the 1980's we printed the first ETDRS charts and developed the first standardized viewer, The ETDRS Illuminator Cabinet . Our cabinet and charts quickly became and remain the benchmark worldwide for studies, trials and general practice. Since our beginning we have manufactured a variety of pediatric testing tools, charts and tests for numerous purposes including low contrast, low vision, visual field, color tests and more. On the forefront of pediatric testing with HOTV and other symbols we now introduce our newest development in the Patti Pics pediatric test system. With the addition of a fifth optotype Patti Pics have been designed to meet acuity test standardization criteria. They are also the only five symbol test with optotypes blurring equally at threshold while following the Snellen principal with calibration targeted to the ETDRS Sloan letter charts. This test system provides a more direct correlation from symbols to letters while lowering probability of guessing correct answers during tests and screenings.