1	Conductive Keratoplasty (CK)
2	How the eye works Light rays enter the eye through the clear cornea, pupil and lens. These light rays are focused directly onto the retina, the light-sensitive tissue lining the back of the eye. The retina converts light rays into impulses, sent through the optic nerve to your brain, where they are recognized as images. 70% of the eye's focusing power comes from the cornea and 30% from the lens.
3	Refractive errors Inability to see clearly is often caused by refractive error. Four types of refractive error: Myopia (nearsightedness) Hyperopia (farsightedness) Astigmatism Presbyopia
4	Refractive errors: myopia In myopia (nearsightedness), there is too much optical power in the eye The distance between the cornea and the retina may be too long or the power of the cornea and the lens may be too strong. Light rays focus in front of the retina instead of on it. Close objects will look clear, but distant objects will appear blurred.
5	Refractive errors: hyperopia In hyperopia (farsightedness), there is too little optical power. The distance between the cornea and the retina may be too short. Light rays are focused behind of the retina instead of on it. In adults (but not children), distant objects will look clear, but close objects will appear blurred.
6	Refractive errors: astigmatism In astigmatism, the cornea is curved unevenly—shaped more like a football than a basketball. Light passing through the uneven cornea is focused in two or more locations. Distant and close objects may appear blurry.
7	Refractive errors: presbyopia Presbyopia is an age-related condition in which your eyes gradually lose the ability to see things up close, because the lens of the aging eye can no longer change shape. When we are young, the lens in our eyes is flexible and is able to change focus easily between near and far objects, like an autofocus on a camera. At around age 40, this flexibility begins to gradually decrease, making it more difficult to see objects up close, unless the eye has nearsightedness.
8	What is refractive surgery? A group of outpatient surgical procedures used to alter how your eye focuses light rays on the retina, thereby improving vision and reducing dependence on glasses and contact lenses. In most cases, refractive surgery affects the shape of your cornea to redirect how light is focused onto the retina. Popular procedures include LASIK, LASEK, PRK and CK.
9	What is refractive surgery? Most refractive surgery is performed on the cornea and affects only the front of your eye, while the rest of your eye will change naturally as you age. In some cases, refractive surgery procedures don’t reshape the cornea; instead, the eye’s natural lens is either replaced or enhanced by an implantable lens that helps correct vision.
10	What is Conductive Keratoplasty (CK)? A non-invasive, thermal refractive surgical procedure used to correct mild to moderate farsightedness (hyperopia). CK uses controlled amounts of radio frequency to alter the shape of the cornea to refocus light rays on the retina to improve vision. CK is for the temporary reduction of hyperopia; for most people the amount of correction will decrease over time.
11	CK for Presbyopia CK can be used to achieve “monovision” (or “blended vision”). With monovision, CK can be used to improve close-up vision in a presbyopic eye with good vision but poor near focus. To maintain good distance vision, usually only one eye is set to near focus (the non-dominant eye), while the other is left or set at good distance vision. Monovision can be achieved with CK (or other refractive surgery), or with contact lenses.
12	How is CK performed? In addition to a complete eye examination to be sure that the eye is healthy, a pre-operative eye exam should also include these measurements to give the surgeon the necessary information to perform the procedure: Refractive error measurement. Pupil evaluation and measurement. Tonometry: measurement of your eye’s intraocular pressure (fluid pressure inside your eye). Corneal topography: mapping the surface details of the cornea. Pachymetry: measurement of corneal thickness.
13	How is CK performed? Your ophthalmologist (Eye M.D.) uses a tiny probe that releases controlled amounts of radio frequency to apply heat to the peripheral portion of the cornea.
14	How is CK performed? The heat then causes the peripheral cornea to shrink and to tighten like a belt.
15	How is CK performed? This increases the curvature (steepness) of the central cornea, increasing the optical power of the central cornea.
16	How is CK performed? This change to the cornea moves the point at which light is focused on the retina.
17	Considerations for CK surgery CK is a non-invasive procedure using radio frequency, which does not remove any corneal tissue. Patients with mild to moderate hyperopia may benefit from CK. Less invasive procedure than intraocular surgery, thus reducing quality-of-vision complaints.
18	Considerations against CK surgery Not for people with any forms of myopia or astigmatism. For patients who desire immediate results, recovery of your best vision may be slower than after having LASIK. (Vision may fluctuate for several days after having CK.) CK may not be a permanent correction; hyperopia may return over time and re-treatment may be necessary. As the eye continues to age, you may need reading glasses for some near vision activities. Patients with poor eye health are not candidates.
19	Risks and possible side effects of CK surgery Over-correction or under-correction (with a possible need for a re-treatment). Induced astigmatism that requires additional treatment. Infection (rare).
20	Is refractive surgery right for you? Advanced surgical procedures, including CK, are creating more opportunities for people who want to be less dependent on glasses or contacts. Surgery may not entirely eliminate your need for corrective lenses. Glasses/contacts may still be needed for activities such as fine or detailed work, reading and perhaps night driving.
21	Is refractive surgery right for you? A large part of the success of any refractive surgery depends on your understanding of the procedure and your expectations. Since refractive surgery is an elective procedure, you have the opportunity and responsibility to become fully informed about its risks and benefits. Your ophthalmologist will explain the specific technique, its benefits, as well as possible risks and side effects associated with your case.
22	Discuss options and questions with your ophthalmologist With the help of your ophthalmologist, it’s ultimately your responsibility to weigh the risks and side effects of a procedure with the benefits it has to offer. If you decide refractive surgery is right for you, you may join millions of people who have reduced their dependence on glasses or contacts.