Installing a central air conditioner costs on average $2650, although it can cost as much as $15,000. This installation cannot be considered a DIY project, and it is traditional for a homeowner to hire a contractor for the job. Cost breakdown.
If the light blue iris ring you are seeing is at or near the margin between the iris (colored part of your eye) and the sclera (white part) and forms a large ring around that margin it is likely to be a deposit of cholesterol. It does not damaging to the eye and does not interfere with vision.
Other causes of headaches that are situated behind the eye include: Tension headaches are some of the more common headaches that develop behind the eyes. This can be caused by stress, eye strain or lack of sleep. These headaches normally go away as soon as the individual gets enough rest. Headaches behind the eyes may be due to one of the following problems of the eye: