This year’s Global Specialty Lens Symposium (GSLS) featured numerous posters highlighting many fascinating areas of specialty contact lenses. There were several novel posters related to multifocal contact lenses, two of which I’ll discuss here.

Decentered Multifocal Optics

Stephanie Ramdass, OD, MS, and colleagues presented a poster titled “Objective & Subjective Visual Response to Decentered Multifocal Optics.” The poster discussed how simultaneous optic designs in soft contact lenses utilize concentric optics under the assumption that they align with a wearer’s visual axis; however, this may not always be the case.

Two pairs of lenses were ordered for each of the 21 subjects enrolled in this study; one had the near-center multifocal optics in the center of the lens where they are traditionally placed, and the other had the optics displaced nasally by 1.0mm.

The fit of the lenses was evaluated at the slit lamp, and topography was performed over the contact lenses to measure the amount of mismatch between the multifocal optics within the lens and the patients’ visual axis (Figure 1). Both distance and near vision was assessed with LogMAR visual acuity, and subjects were asked to rate their binocular distance and near acuity on a scale of 1 to 10 (with 10 being best, 1 being worst).

The authors reported that in evaluating the mismatch between the near optics of the lens and the visual axis of the subjects for the zero-offset lenses, 100% of measured mismatches were located temporal to the visual axis, compared to 61% of the 1.0mm offset lenses. There was no statistically significant (p < 0.05) difference in objective measurement of distance visual acuity with either lens pair (p = 0.43). However, there was statistically significant difference at near viewing (p = 0.04) and in subjective responses when viewing various targets.

Though they received each lens design, subjects were blinded to which optical design they were wearing; impressively, 19 of the 20 subjects who completed the study favored the pair with the offset near optics. The authors stated that “quality of vision can be improved by nasally decentering the optics in near-center multifocal lenses,” and that further analysis is ongoing.

Correcting Presbyopia Post-LASIK

Receiving an award in the clinical category was Nicholas Gidosh, OD, for his poster titled “Topography guided empirical contact lens fitting in correcting presbyopia after LASIK.” Dr. Gidosh reported that though improvements have been made in laser-assisted in situ keratomileusis (LASIK) surgery in recent years, patients may still report symptoms of glare, ghosting, monocular diplopia, and reduced contrast. These symptoms may be secondary to “decentered ablations, ablation asymmetry, flap striae, and small treatment diameter.”

The case described involved utilizing corneal topographic data to design a reverse geometry GP contact lens to better align the oblate post-LASIK cornea and take advantage of the symmetrical back optic zone and tear lens to correct irregularities present in the cornea. Dr. Gidosh concluded that reverse geometry corneal lenses can center well and, through this centration, provide a platform to place multifocal center-distance optics on the front of the lens to deliver near correction in presbyopia.

Learn More

You can find the complete list of this year’s GSLS posters at www.gslsymposium.com/posters2018 . CLS