Ophthalmologists, specifically refractive surgeons, along with their patients, have enjoyed huge success with ablative (corneal tissue removal) procedures over the 30 years since Dr Marguerite McDonald performed the first PRK on a sighted eye in New Orleans on 25 March 1988
How things have developed since then, with the advent of LASIK, LASEK, TE-PRK, FemtoLASIK and SMILE—a plethora of tools that allow the refractive surgeon to select the most appropriate procedure for each patient. All these procedures modify the corneal shape by removing corneal tissue, thereby correcting the refractive error. LASIK has become the most studied and most successful elective procedure, with the highest patient satisfaction rating of any elective procedure.
So why are we looking for even more options? There are several reasons, most of them related to shortcomings of the ablative procedures. All procedures that remove corneal tissue reduce the corneal biomechanical strength to some extent.
At one extreme is a thick-flap microkeratome LASIK and at the other are PRK and SMILE, which maintain more biomechanical strength.
Dry eyes are less of an issue today thanks to heightened awareness and the tools that we have at our disposal to treat dry eye prior to surgery.
There are some refractive errors that simply don’t do particularly well with ablative techniques; for example, high hyperopia and conditions like keratoconus. Presbyopia remains the last refractive challenge, and potentially represents the biggest market. Besides monovision/blended vision, there are no widely adopted corneal ablative refractive procedures to treat presbyopia.
Also, market research indicates that some people steer away from the ablative techniques as they feel they are too permanent and non-reversible. Some might think a permanent outcome would be a bonus but not all patients agree.
Dr Cummings is based at Wellington Eye Clinic, Dublin, Ireland. He is an investigator for Allotex but has no nancial interest in the company, and is on the Medical Advisory Board of Vivior.