GP Findings From the GSLS
By Edward S. Bennett, OD, MSEd, FAAO
The Global Specialty Lens Symposium (GSLS), held Jan. 27 to 30 at the Paris Hotel and Casino in Las Vegas, was once again a very informative conference. This column highlights some of the important GP findings from the meeting.
Earl Smith, III, OD, PhD, reported on his continuing work with retinal focus and defocus. In myopia there is typically peripheral hyperopic defocus. A mechanism to create peripheral alignment or even slight myopic defocus could significantly reduce axial length growth. Although several possible methods could potentially produce this effect, in his opinion the most aggressive treatment would be an orthokeratology-like design.
Interestingly enough, one of the scientific poster award recipients was Jaume Pauné Fabré, MSc, who reported—via a small subject sample—on the clinical performance of a new peripheral refraction control GP lens for myopia stabilization.
Paul Gifford, PhD, reported on research he has been performing with Helen Swarbrick, PhD, pertaining to hyperopic overnight ortho-k. He found that there was good refractive and topographic predictability up to 1.50D of hyperopia. Greater than 1.50D of hyperopic reduction is possible, but less predictable as there appears to be less of an effect on corneal shape as with myopic individuals.
Pauline Cho, PhD, reported on the results of several new studies including the Retardation of Myopia in Orthokeratology (ROMIO) and Toric Orthokeratology-Slowing Eye Elongation (TO-SEE). In the ROMIO study, with subjects having less than 1.25D of corneal astigmatism, she found a 41-percent reduction in axial length progression versus the control group after one year. In the TO-SEE study, in which subjects entered with corneal astigmatism between 1.25D to 3.00D, there was a significant reduction in both refractive error and in corneal astigmatism.
Langis Michaud, OD, found in a comparison study that 75 percent of keratoconus patients preferred a semi-scleral 14.0mm lens versus 16.6 percent for a 10.2mm lens, and 8.4 percent exhibited no preference. He predicted that within three years, most keratoconus patients will be fitted into large-diameter lenses.
Sameer Ganu, MOptom, reported on a population of 133 eyes with corneal ectasia that had a history of corneal cross-linking, penetrating keratoplasty, or intrastromal rings and were fitted into scleral lenses. He found that 90 percent of the patients were able to achieve a visual acuity of 20/30 or better with scleral lenses; 80 percent had not been able to tolerate smaller-diameter GPs.
Greg DeNaeyer, OD, reported on care of scleral lenses and recommended Progent (Menicon) or Optimum Extra Strength Cleaner (Lobob). He also reported that a recent I-Site (International Newsletter and Forum on GP Contact Lenses, Corneal Shape, Health, and Vision) survey showed that 22 percent of practitioners were using a preserved GP solution for applying scleral lenses. These solutions are contraindicated as they can ultimately be toxic to the cornea.
Care and Compliance
Dr. Cho reported that the most common noncompliant behavior pertained to inadequate cleaning of cases (61 percent, as opposed to 13 percent for inadequate cleaning of lenses and 11 percent exhibiting poor hygiene), and the lens case represented the major source of contamination. She emphasized allowing the case to air dry after cleaning, which significantly reduces microorganisms. She also indicated that 79 percent of patients would replace their case if a new one was provided with every bottle of multipurpose solution. CLS
Dr. Bennett is assistant dean for Student Services and Alumni Relations at the University of Missouri-St. Louis College of Optometry and is executive director of the GP Lens Institute. You can reach him at email@example.com.