SoftSpecialEdition is a quarterly newsletter FOR HEALTH CARE PROVIDERS that gives independent updates from the international literature on soft specialty lens-related topics. View as Webpage
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World Wide Vision XXXXVII
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Soft Contact Lenses in Dry Eye: Friend & Foe
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Dry eye disease is a complex inflammatory condition that continues to challenge patients, eyecare practitioners and manufacturers alike. This became even more evident during the COVID pandemic with an increase in digital device use (resulting in less blinking) and mask-associated dry eye (M.A.D.E). Contact lenses in the dry eye arena can be a friend and a foe. To start with the latter: symptoms of dryness and discomfort continue to be among the main issues leading to contact lens dropouts. Luckily, improvements in polymer technology and innovations in manufacturing continue to bring new contact lens options to market to address vision and ocular surface-related challenges such as dry eye. At the same time, contact lenses can be a friend to those with moderate-to-severe dry eye symptoms; therapeutic or bandage contact lenses are used to manage ocular discomfort, to support the cornea during healing after surgery or when the cornea is being treated for an underlying disease state, or to protect the cornea from the environment or from mechanical interaction with the lids. In addition, soft lenses can be ‘a friend’ in managing allergies, drug delivery to the ocular surface and UV-protection. In short, innovation in contact lens technology continues to evolve in the hopes of addressing numerous contact lens-related challenges faced by patients, including dry eye. Keeping abreast of these advances can differentiate our practices and ultimately benefit our patients. We should realize that soft lenses can be a friend and a foe in dry eye. As an eyecare practitioner, it is an exciting time to manage patients, as we have additional tools in our armamentarium to address these issues in contact lens practice.
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Soft Toric: a Feasible Option for Corneal Ectasia?
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To assess the feasibility of fitting soft toric contact lenses in corneal ectasias and their impact on optical quality and visual performance, 22 eyes were fitted with a molded soft toric lens: 11 eyes with corneal ectasia and 11 healthy eyes. After soft toric lens fitting in the ectatic corneas, oblique astigmatism aberration increased by 0.15±0.17μm and 0.34±0.36μm for 3mm- and in mesopic pupil diameters respectively. Mean defocus aberration decreased too, by 1.41±0.36μm and 2.17±0.85μm for the respective pupil sizes. More positive values of vertical coma were found (0.05±0.06μm and 0.12±0.10μm for 3mm and mesopic pupil diameters). Comparing changes between both groups, statistically significant differences were detected in oblique astigmatism, defocus, vertical secondary trefoil and horizontal secondary coma for a 3mm pupil aperture. In the group with corneal ectasia, photopic high and low contrast visual acuity improved by 0.09±0.11 logMAR and 0.12±0.15 logMAR respectively, while in mesopic conditions this improved respectively by 0.11±0.12 logMAR and 0.18±0.15 logMAR units. In conclusion: the analyzed molded soft toric contact lens was considered a feasible option for good vision in corneal ectasia with moderate irregularity and with negative vertical coma. Photo by Matheo JBTon Unsplash
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Soft Toric Lens Stabilization-Time
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A short-term, prospective, contralateral, randomized, and participant-masked study was carried out involving 20 healthy participants (25.4±2.6 years of age), who were evaluated after the application of two different soft contact lenses at different time points (1, 5, 10, 20, 30 minutes after application). Except for comfort and contrast sensitivity, the values of all of the parameters stabilized 10 minutes after the application of both soft contact lenses. In conclusion, it would be possible to properly evaluate high-contrast visual acuity, low-contrast visual acuity, and in vivo wettability 10 minutes after the application of both soft contact lenses, the authors conclude.
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Pupil Size & Optimal Optic Zone Diameter in Multifocal Simultaneous Lenses
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The purpose of this study was to determine the impact of different central optical zone diameters (COZDs) in relation to pupil size on the visual performance of presbyopic subjects fitted with center-distance simultaneous multifocal (MF) contact lenses. Thirty-two presbyopic patients between 45-58 years of age volunteerd for this prospective, controlled, double-blind study. Subjects were fitted with 5 center-distance MF lenses of variable COZDs, corresponding to 60%, 70%, 80%, 90% and 100% of pupil diameter under photopic light conditions. Statistically significant differences were obtained for both distance and intermediate visual acuity between designs: best results were obtained with 80% and 90% COZDs. The investigators conclude that MFs with COZDs of 80-90% and of 90-100% of photopic pupil diameter offered better distance and intermediate visual acuity, without a decline in near performance and with superior contrast sensitivity at medium and high spatial frequencies compared to lower COZD designs.
Photo by Nathan DeFiesta on Unsplash
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Common Myths and Misconceptions in Soft Lenses
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Karen Walsh, Lyndon Jones and Kurt Moody discuss and address 10 common myths and misconceptions in soft contact lens practice, which are certainly also applicable to specialty soft lenses. 'Increasing oxygen transmissibility improves lens comfort', 'Hydrogels should no longer be fitted', 'Patients will be more successful wearing contact lens materials that demonstrate low levels of deposition', 'Young children are less successful with contact lenses', 'Multifocal fitting is not successful' and 'Patients with low astigmatism do fine with spherical lenses' are discussed in detail and in an evidence-based manner. In addition, a few business-focused barriers are considered, including: 'Focusing on growing my contact lens business is too time-consuming' and 'My contact lens business will not grow because as many patients as I fit end up dropping out'. A must read for anyone who wants to understand the complexity of soft contact lenses. Photo by aisvri on Unsplash
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Soft Multifocal Lenses for Myopia Management
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This randomized, single-blind clinical trial compared the effectiveness of multifocal soft contact lenses and orthokeratology (ortho-k) treatment to single-vision spectacles for myopia control. Sixty-six Chinese children aged 7 to 15 years with cycloplegic refraction measurements between −1.00D and −8.00D and astigmatism not more than 1.00D were randomly assigned to any of the three treatment options and followed for 1 year. Myopia progression in the spectacle group was greater than in the contact lens treatment groups. Soft multifocal lenses reduced the rate of myopia progression in diopters by 37.0% compared with glasses. The reduction in axial length was 26.8% in the multifocal group and 24.4% in the ortho-k group. So, compared with single-vision glasses, wearing multifocal soft or ortho-k lenses significantly delayed myopia progression in this study. The gap between the two (which used to be in favor of ortho-k) seems to be narrowing. Multifocal and ortho-k lenses are promising methods of myopia control, the authors state.
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Myopia Management - One Child at a Time
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A new book on myopia management based on 'The Montreal Experience' is available now as a digital edition and in print. It covers in detail all intervention methods, but it surely also digs into soft lens options. In particular, the book reinforces the fact that myopia management must be customized according to the patient, as different optics may lead to different outcomes. The Montreal Experience implies that the design of contact lenses must take into account the physiological parameters of the patient. There are two ways to increase the dose of myopic defocus on the retina and to influence its response. First, a larger area of myopic defocus causes a slowing of myopia progression, and second, it is possible to increase the signal strength by increasing the power of the addition. Both can potentially be applied in a controlled manner with custom-made soft lenses. Choroidal volume analysis is a new and promising means to evaluate the ocular response to any of these visual stimulations; it may be a convenient means to test, in the short term, the individual response and to determine the best strategy for a given patient, according to the authors.
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Global Myopia Symposium Virtual 2022
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Registration is now open for Global Myopia Symposium 2022. On September 8-10, join GMS for three days of panel discussions and sessions covering topics like unilateral & anisometropic myopia, new research findings and the application of soft lenses in myopia management.
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