Dr. Edward Boshnick's presentation to the FDA Joint Advisory Panel on 2/24/2015 regarding Avedro's application for approval of riboflavin/UVA corneal collagen crosslinking:
I'm Dr. Edward Boshnick. I'm an optometrist in Miami, Florida. I have been in private practice for 45 years and before that for 2 years in the U.S. Army Medical Service Corps. My practice for many years has been limited to a specific patient population, mainly patients who have experienced loss of vision due to refractive eye surgeries such as LASIK and Radial Keratotomy, keratoconus, corneal transplant surgery and so on. Over the years I have taken care of thousands of keratoconus patients. In addition, I have also taken care of several thousand patients who have lost vision due to post-LASIK ectasia and other complications due to LASIK and other refractive surgical procedures.
Avedro has a financial interest in the corneal collagen crosslinking controversy. I have no financial interest in this industry so I will write what I consider to be the truth as I know it.
Keratoconus is a genetically determined condition that is progressive in nature. However, the progression is not open ended. By that I mean that the condition has a beginning, and an end. Usually the active period lasts for about 5 years. I can understand that a patient, especially a child who is recently diagnosed with keratoconus may face a number of years with the possibility of progression. I think that in cases such as this, cross-linking may be a viable option to consider. However, in an adult who has had to deal with keratoconus for many years, it may not be a realistic choice. Again, over the life of a keratoconic patient, the corneal topography will exhibit minor changes, whether or not cross-linking is done. This is normal. Very rarely will I have to make changes to a contact or scleral lens design due to progression in an adult patient. However, small changes to the corneal topography may lead me to change a contact or scleral lens design. Again, small changes over time to the corneal topography (and ocular surface) is normal over time regardless if Cross-linking is done or not.
Corneal ectasia is a different matter entirely. LASIK is a procedure that thins out the cornea. A "normal" cornea is about 550 microns thick. After LASIK is done the corneal thickness may be reduced to 350 microns or less. Over a period of years the pressure from inside the eye against this weakened corneal "wall" can cause the cornea to buckle or "pop". We call this ectasia. It has been my experience that this takes place rather suddenly with an active period that can last several weeks to several months. The great majority of patients who I have seen with ectasia have relatively stable corneas for many years following the onset of the condition. In addition, my patients with ectasia who did undergo cross-linking have corneal topographies very much the same as their topographies before cross-linking was done. Again, because we are dealing with soft tissue (as opposed to bone) it is normal for small changes to take place in the corneal topographies and on the ocular surface over time.
Please understand that the comments and observations above are mine and based on what I have seen and experienced. I did not do any controlled studies involving progression on any of my patients with keratoconus or ectasia.
I must add that the emotional impact of surgically-induced corneal ectasia is often quite severe. Many of my patients have expressed thoughts of suicide. These are patients who had healthy eyes with good correctable vision before being sold an unnecessary refractive surgery. The FDA must ensure that cross-linking will not be misrepresented to these patients as a treatment that will undo the damage.
I suggest that the panel recommend limiting the product to cases with active progression, and include all applicable risks, precautions, and warnings in the labeling to be given to prospective patients so that they can make an informed decision.
Disclaimer: The information contained on this web site is presented for the purpose of warning people about LASIK complications prior to surgery. LASIK patients experiencing problems should seek the advice of a physician.