Lisbon, Portugal—If presbyopia is the "final frontier" in refractive surgery, which surgical approach will stand out as the winner in treating patients with the condition? Will it be corneal surgery, intraocular surgery, or phakic-versus-pseudophakic approaches? Samuel Masket, MD, asked at the European Society of Cataract and Refractive Surgeons (ESCRS).
Dr. Masket, who is clinical professor, Jules Stein Eye Institute, Los Angeles, and in private clinical practice in Los Angeles, attempted to answer these questions during an ESCRS symposium on the surgical correction of presbyopia. He reviewed many of the evolving approaches available to ocular surgeons and outlined where ophthalmology is now and where it is headed in the treatment of presbyopia.
"There is great interest and excitement in this arena," he said.
While scleral-expansion surgery has not fared well with respect to the peer-review literature, there is still interest in this area, Dr. Masket pointed out. SurgiLight Co. (Orlando) has developed a proprietary laser to create radial partial-thickness scleral ablation to allow scleral expansion. However, this concept of accommodation is not widely accepted, he added.
Consider the issues
In directing his comments to the more accepted concepts for accommodation, Dr. Masket said there are a few issues surgeons need to consider when looking at the new devices. These issues will ultimately determine the winning concepts.
Regarding pseudoaccommodation, some IOLs are already well established, but there are new pseudoaccommodative concepts under development, he pointed out, with respect to phakic IOLs, corneal excimer photoablations, and corneal inlays.
"With all pseudoaccommodation, there is a variable loss of contrast sensitivity function and perhaps induction of optical side effects," Dr. Masket said.
With respect to true accommodation, Dr. Masket explained that transient changes have to be instant and reversible inside the eye.
"The hope is that true accommodation will be associated with a higher quality of vision without loss of contrast sensitivity function," he said.
Dr. Masket reviewed some of the excimer laser-based surgical approaches, but refractive surgeons have the opportunity to use the cornea for an inlay. He mentioned the AcuFocus Corneal Inlay, an ultra-thin device that is placed within a LASIK bed and based on the small optical aperture, or pinhole effect. The device increases the depth of focus but does not produce distance vision.
"The polymer is biocompatible and microperforated and allows nutrient flow into the cornea. The overall diameter is 3.8 mm and the aperture is 1.8 mm," he said. The device is implanted in the nondominant eye.
The results with the AcuFocus inlay indicate that the preoperative uncorrected visual acuity was 20/20 and poor near visual acuity, and after implantation the patients had good near vision as the result of pseudoaccommodation through the aperture effect.