Intra-Corneal Rings

by David A. Wallace MD

Intra-Corneal Ring © All Rights Reserved.

This is a procedure involving the insertion of curved clear plastic ring segments into the mid-peripheral cornea.  Intacs rings were originally intended for treatment of very low amounts of nearsightedness, and secured FDA approved for this application in about 1999.  It is not a treatment for astigmatism; in some cases, astigmatism is actually worsened. About 15% of patients in initial clinical studies have subsequently requested removal of the ring segments. Intacs' manufacturer has tried to put a positive spin on this, touting that the procedure is 'reversible'. Why anyone would want to have surgery, then have it undone, still baffles some of us.

Intacs rings are now almost exclusively used as a salvage or temporizing treatment in cases of abnormal corneal curvature, with asymmetry and/or  distortion of normal anatomy.  Typically, it is used now in the context of keratoconus or post-LASIK ectasia, where the implanted ring segments are thought to act by buttressing or structurally supporting an area of otherwise weak corneal tissue.  Some surgeons report favorable results in some of these cases, but I have personally not been impressed with either the predictability or uniformity of these results.  Even with imperfect predictability of results, this procedure is a reasonable option in certain situations involving abnormal or distorted corneal curvature (due to thinning and/or biomechanical bulge), which may delay or avert the need for more invasive, higher-risk procedures such as corneal transplantation.