Conductive keratoplasty (CK) is a relatively new type of refractive surgery that uses mild heat from radio waves to shrink the glue-like connective tissue (collagen) in the periphery of the cornea. This steepens the cornea, giving farsighted patients with presbyopia better near and distance vision while improving near vision for patients with presbyopia alone.

 
     
 

Conductive Keratoplasty is a contact technique which uses a thin-tipped probe to introduce controlled radio frequency energy into the stroma of the peripheral cornea (see diagram shown here). The treatment increases the temperature of the cornea consistently to 65degrees C throughout 75% of its depth. This ultimately leads to permanent shrinkage of the deep column of collagen measuring l00 microns wide by 500 microns deep.

 
 
     
 

To qualify for CK correction of hyperopia, you must be 40 or older and have between +0.75 and +3.25 diopters of refractive error, with no more than 0.75 diopters of astigmatism. Also, your glasses or contact lens prescription cannot have changed within one year before the surgery.

To make sure CK correction of presbyopia is right for you, your eye surgeon may test you with a trial period of wearing monovision contact lenses in which one eye is corrected for near vision and the other eye is corrected for far vision. Or, the surgeon may determine if you are a good candidate for monovision correction by holding a test lens in front of your non-dominant eye to make sure your distance vision remains sharp. CK treatment parameters for presbyopia allow induction of myopia in the eye being corrected for near vision between a range of -1.00 to -2.00 diopters. As with hyperopia correction, your glasses or contact lens prescription cannot have changed within one year before the surgery.

  
     
 

The clinical trial data that was used for the FDA approval was collected at the 12-month follow-up visits made by patients. Here are some of the results:

  • 98 percent of patients could see magazine- or newspaper-sized print in the treated eye.
     
  • 87 percent could see 20/20 in the distance and also read phonebook-sized print, which is signifcantly smaller than newsprint.
     
  • No patients reported serious, sight-threatening, or unanticipated safety events.
     
  • During the clinical trials, every patient showed improvement in near vision.

One attractive feature of CK is that it is minimally invasive. Some patients experience tearing, foreign-body sensation, and/or vision fluctuation, but this is normally temporary.

 		 
     
 
Conductive Keratoplasty Procedure >