We now have substantial evidence that soft multifocal lenses (MFs) can significantly slow progression in myopic children. Studies of a range of different lens designs across different populations show that MFs can slow myopic eye growth, typically by between 30 to 60%. From an optical point of view, MFs that have a central distance zone and a more peripheral near zone introduce increased levels of spherical aberration that result in greater positive refractive power (resulting in myopic defocus) in the marginal pupil region. While MFs have been shown to influence accommodative posture and binocular vision characteristics, the most likely mechanism is the impact of the positive refractive power (myopic defocus, in which light is focused in front of the retina) that is introduced by the MFs. There is new evidence of an apparent dose-response effect associated with the optical properties of the lenses, suggesting the promising possibility that further improvements in myopia control efficacy may be possible, with optimised optical designs that introduce higher levels of myopic defocus. The optical effects of the lenses will interact with the natural aberrations and pupil size of children’s eyes. Thus, an improved understanding of the optics of myopic children’s eyes - and how this interacts with treatment effects - may assist in the design of novel approaches for increased efficacy. The eye’s aberrations also change during accommodation (with an increase in negative spherical aberration typically noted); therefore, understanding how the optics change during accommodation and how they interact with the optical effects of lenses and their treatment effects is another important area. While it is clear that there is significant work needed, results to date suggest that clinically significant effects can be achieved with current lens designs, with the promise of improved outcomes in the future as our understanding of the optical effects on eye growth continues to improve. More on this @ GSLS 2021.

While the understanding of the overall sag values of the ocular surface (the OC-SAG) is increasing, the knowledge of CL-SAG values of different soft lenses that are used on a daily basis in clinical practice is limited. In a paper by Stapleton and Tan, as a follow-up to the Tear Film and Ocular Surface Society (TFOS) contact lens discomfort workshop, it was stated that “both base curve and diameter are surrogate measures for lens sag,” in which ‘sag’ is referring to CL-SAG. A study from Pacific University (USA) sheds some new light on the variation in CL-SAG among different lenses using a new instrument based on OCT technology that can directly measure posterior CL-SAG in a hydrated environment. Marked differences in CL-SAG between lenses were found in this study in a large collection of daily disposable, reusable (2-week and 4-week replacement) and toric lens designs; both between these groups and within each lens group. Lens diameter and base curve (BC) both have a substantial influence on CL-SAG. Lenses of the same BC can have marked differences in CL-SAG, indicating that if lens substitution is done by patients or by eye care practitioners (ECPs) based on BC alone, then the lenses in terms of CL-SAG will not be identical in shape, with a potential impact on lens behaviour on-eye. The difference in CL-SAG between lenses of the same type offering two different BCs has a somewhat narrow band in absolute terms; this means that the tools for ECPs to fit all eyes with the standard arsenal of lenses can be restricted as well to a degree. Switching from a spherical to a toric lens of the same lens manufacturer and basic nomenclature can result in a significant change in CL-SAG for one lens design, with almost no change in CL-SAG for another lens design. More on this @ GSLS 2021.

Brought to you by Contact Lens Spectrum, GSLS is the leading national contact lens conference in North America, with delegates attending from over 35 countries. The 3-day conference focuses on the successful management of ocular conditions using today's specialty contact lenses through continuing education and workshops - but has a truly international flavor. Soft specialty lenses topics will surely be represented on the program. Registration for GSLS 2021 is complimentary to all attendees this year.

While available parameters of commercial available lenses may address the needs of many of your patients, they will not meet the visual or anatomic requirements of every patient, writes Matthew Lampa. When a standard soft contact lens falls short in satisfying a patient’s needs, a custom soft lens can fill the gap. In addition to all kinds of optical options, custom soft lenses are indicated when the size and shape of the eye yield a sagittal height profile that cannot be matched with standard soft lens base curve and diameter options. Custom soft lenses are manufactured in a wide range of base curves and diameters, often in as little as 0.1mm steps. This enables practitioners to fit a broad range of corneal curvature and diameter combinations. In addition, a significant advantage of custom soft multifocal contact lenses is that, depending on the manufacturer, the optical profile within the lens can be optimized for an individual patient’s ocular characteristics and visual needs. For example, the sizes of the near and distance zones can be adjusted to respect a patient’s unique pupil size and vision demands. Also, some manufacturers can further customize the multifocal correction by decentering or offsetting the optics in the lens so that they align with a patient’s line of sight, which may not be lined up with the geometric center of the lens. And there also indications and design considerations with regard to custom soft lenses for patients who have irregular astigmatism. As alluded to in the fall edition of softspecialedition.com: the next 10 years could become the The Decade of Soft Specialty Lenses.

Applicable to both specialty lens practice and to any general contact lens practice supposedly, part of this study out of Valladolid (ES) focused on the question of whether a placebo effect exists in contact lens discomfort management? The literal meaning of 'placebo' from the Latin origin is 'I shall be pleasing'. One group of the participants in this study got new lenses, but another group (the control group) were provided with a new pair of their habitual monthly disposable lenses; however, these participants were informed that these lenses were a new brand. After one month of wearing the masked monthly lenses, contact lens discomfort symptoms showed a significant improvement in this group despite wearing the same old lenses. The investigators conclude that clinicians and researchers must be aware of the existence of a placebo effect when assessing the effectiveness of any contact lens refitting. A complex matter that may need further thought when you consider that the placebo effect could be amplified when doctors appear likeable and competent and that resilient, friendly people are more responsive to placebo treatment.