The light rays are refracted by the cornea onto the lens. The light rays are refracted a second time whilst passing through the lens and focussed onto the retina â the light sensitive part of the eye. The image formed on the retina is inverted (upside down) and real (the light rays travel through the image).
Nationally, professionally-installed radon mitigation system costs average $1,200, but range from $800 to $1,200 in Colorado, assuming there aren't any problems encountered during installation.*. Costs are highly dependent on what is required to vent the radon and how to route it through the house.
1 Fix the home if the radon level is 4 picoCuries per liter (pCi/L) or higher. 2  Radon levels less than 4 pCi/L still pose a risk, and in many cases, may be reduced. 3  Take steps to prevent device interference when conducting a radon test.n a new home, the cost to install passive radon-resistant features during construction is usually between $350 to $500. In some areas, the cost may be as low as $100. A qualified mitigator will charge about $300 to add a vent fan to a passive system, making it an active system and further reducing radon levels.