Prescribing for Presbyopia
Presbyopia Posters at GSLS
BY CRAIG W. NORMAN, FCLSA
The Scientific Poster Section of the 2015 Global Specialty Lens Symposium (GSLS) presented 70 different projects. Following are highlights of the posters on presbyopia.
Notable Posters on Presbyopia
How Important Is Optical Placement in Multifocal Lenses? (Brujic) Although many factors contribute to the success of multifocal contact lenses, the alignment of the lens optics may be the most critical. Many researchers have studied the visual impact of the difference in patients’ line of sight versus the cornea’s geometric center and have surmised that possibly displacing the near optics of soft, simultaneous design multifocal contact lenses over patients’ line of sight can optimize their visual performance. Results from a single case report plus four additional subjects wearing a proof-of-concept custom prism-ballasted design from SpecialEyes demonstrated a subjective improvement in near vision for all of the study participants. Dr. Brujic surmised that this may be a viable strategy for future investigation with larger numbers of patients to determine the true magnitude of improvement.
Visual Performance Comparison between Duette Progressive and Air Optix Monthly Multifocal (Montani) Following baseline measurements, 15 presbyopes who had not previously worn contact lenses were randomly selected to wear either Duette Progressive (SynergEyes) or Air Optix Aqua Multifocal (Alcon) contact lenses for two weeks, then switched to the other lens type after a brief washout period. The results demonstrated that both contact lens types modify high-order aberrations (HOAs), with spherical aberrations (SAs) changing from positive to negative with increased range of focus. Coma also increased, more so with the soft lenses, most likely due to the misalignment between the lens center and the line of sight. The hybrid lens reduced trefoil more compared to the soft lenses, likely because the GP center reduced the HOAs induced by the anterior cornea. He concluded that the Duette Progressive can be considered an effective modality for providing optimal visual results and comfort similar to a soft lens.
Visual Performance of a Translating GP Multifocal Contact Lens in Correcting Presbyopia (Montani) In five subjects who were previous monovision GP wearers and three who had no previous contact lens experience, monocular and binocular high-contrast visual acuity (VA) with Expert Progressive (Essilor) lenses was not significantly different from best ophthalmic correction. A statistically significant reduction was found only for the monocular and binocular low-contrast VA for far and intermediate distances, but it was not clinically significant because the differences were less than one VA line. In spite of the greater thickness of the translating design, all subjects rated comfort more than acceptable. The progressive translating GP lens provided optimal visual results for all distances.
Visual Acuity and Ocular High Order Aberrations as a Function of Base Curve and Add of Soft Multifocal Contact Lens (Montani) Data obtained from 15 eyes demonstrated a general tendency of SA to change from a positive value without lenses on the eye toward a more negative value with lens wear. Greater changes occurred with those lenses that were well centered and had higher add powers. Lenses with flatter base curves (BCs) decentered more compared to the other BCs trialed, and their effects induced a greater amount of coma plus lower high- and low-contrast VA. As the majority of soft multifocal lenses are available with only one BC, he postulated that the resulting inability to improve the position of a decentered contact lens may be an explanation as to why the overall success rates with soft multifocals remains relatively low. CLS
For references, please visit www.clspectrum.com/references and click on document #232.
Craig Norman is Director of Research, Michigan College of Optometry at Ferris State University. He is an advisor to the GP Lens Institute and has received lecture or authorship honoraria from B+L and TruForm Optics. You can reach him at CraigNorman@ferris.edu.