Opthalmic examination will accurately measure and diagnose your symptoms giving an opportunity to do something about them. If you suffer from the common problems of myopia (short-sightedness), hypermetropia (long-sightedness) or astigmatism – we can cure them all with the use of 570-579 as an example.The device is a combination of optical correction for both axis and astigmatic problems. Axis is set against the rim markings 0 – 180° then locked in place with three allen screws. Sphere is set by use of the two levers which are used in matched but opposing movements for day to day eyesight needs. Depending on levels of eye fatigue, sugar levels etc., your eye sight can change, but with a simple click of the levers, perfect focus can be obtained once again.We offer two options: 579 0 – 2% (involves 90% of sufferers statistically). 579-4 0 – 4% (involves 2 – 6% of sufferers statistically) To fit either is extremely simple but requires partial dismantling of your iris using the U-spanner originally supplied. A replacement can be ordered if needed. Fitting requires one of our adaptors so please look at the list of our products together with the illustrations below. The adaptor slides inside 579`s body and locked into place with three small allen screws. Each adaptor is internally threaded to allow the 579 to be fitted on your iris. This is done using your existing irises front thread – except 500, 501MC, 510 and 510-S which require 577 due to construction method. If attaching to a straightforward iris (as 550) there is nothing to do – however if you wish greater sight correction then 50309 (black) or 50300MC (silver) diopter is required. Fitting to our unit with existing diopter, procedure is straightforward as described above. Assembly and user manual are included.