Myopia, and Bringing MiYOSMART® Lenses to Kitsilano, Vancouver
I have just completed my formal training on the newest development by international prescription eyewear lens designer HOYA, the new MiYOSMART lenses. This article gives a one and all look into what this exciting innovation in treating nearsightedness means to children and families in Vancouver, and more importantly why we chose to offer our patients these lenses at Della Optique.
What Is Myopia
Myopia is a condition when the shape of your eye causes light rays to refract and focus in front of the retina. This results in blurring of distance objects. Another word for myopia is simply put, nearsightedness.
Why Myopia Progression Is a Concern
According to one research team, half the world’s population could become myopic by 2050 (1). Another study has shown that the US alone has seen a 66% increase in myopia rates since the 1970s (2). It is very important to monitor how a child’s visual system changes on an annual basis.
Myopia progression is not only a concern in patients who already have a high minus prescription; it is a concern even in lower levels of myopia. If large increases are noted in a short period of time, myopia control practices should be considered as early intervention is key.
With higher levels of myopia there is an increased risk for other vision threatening eye conditions such as myopic maculopathy, retinal detachment, cataracts and glaucoma. One published research paper notes that every 1 diopter increase in myopia shows a 67% increase in the prevalence of myopic maculopathy. (3)
Risk Factors
It is shown that some populations have a greater chance of myopia than others. Some of these factors include:
Genetic factors – ethnicity, age, parental myopia
Optical factors – refractive error, axial length growth, peripheral hyperopic defocus,
binocular vision deficit.
Environmental factors – time spent indoors, extended amount of near work
MiYOSMART Treatment
MiYOSMART eyewear lenses is what you would call a non-invasive treatment option – it’s a spectacles lens. Other myopia control intervention options such as, atropine therapy, orthokeratology, and multifocal soft contact lenses are considered more invasive in nature.
With traditional single vision correction, the central vision light rays land directly on the retina to create a clear image. However, some of the peripheral light rays end up behind the retina. This ultimately creates a hyperopic defocus which causes the eye to react by increasing in axial length, creating a more myopic eye.
Diagram (a). Image borrowed from: Barry Santini, (n.d.) for 20/20 [Web article]. (4) http://reviewofmm.com/myopia-management-abo-ce-for-your-staff/
What we want to do with managing myopization is to bring the peripheral light rays to land in front of the retina, so as to create a myopic defocus. This will prevent the eye from elongating which should slow down axial growth.
Defocus Incorporated Multiple Segments (DIMS)
In the treatment zone, the patented DIMS technology has myopic defocus islands, which have a power of +3.50 diopters, and is distributed in a high density honeycomb structure over a 33 mm area. This specific honeycomb structure allows a 50/50 ratio of clear vision and defocus while looking through the treatment zone.
This means that half of the light rays that enter the eye are focused on the retina (clear vision) and the other half are focused in front of the retina (blurry myopic defocus). The central 9.4mm area has a clear zone with no defocus segments. The MiYOSMART lens basically is a regular lens with full prescription power and then you have micro islands that are on top of it. In between the islands, we find the clear vision.
Diagram (b). Image borrowed from HOYA, 2020. (5)
Diagram (c). Image borrowed from HOYA, 2020. (6)
Our brains are very smart. Thus, even with a 50/50 ratio of clarity/blur created by defocus, our brain will focus on the clear content. This 50/50 ratio has been thoroughly tested and verified to achieve comfortable vision while having an effect on myopia control therapy.
Clinical Studies
Defocus Incorporated Multiple Segments (DIMS) spectacle lenses slow myopia progression, a two year randomized clinical trial has shown.
183 Chinese children aged 8-13 years of age were monitored and it concluded that DIMS lenses reduced myopia progression by an average of 60%, compared to single vision lenses.
In terms of patient suitability, DIMS lenses are suitable for ages 6-18 years and can be prescribed whenever the first sign of myopia appears. There were no adverse effects associated with MiYOSMART lenses, and this was a big part in our decision to implement MiYOSMART at Della Optique in Kitsilano.
MiYOSMART Lens Technicalities
The MiYOSMART lenses coating is easy to wipe and comes with a special anti-reflective treatment. The lenses have scratch resistance, anti-glare, hydrophobic layers, and UV protection.
Visit our online booking page to book your next eye exam appointment
or call us at (604) 742-3937
References:
(1) Holden, Brian A., et al. “Global prevalence of myopia and high myopia and temporal trends from 2000 through 2050.” Ophthalmology 2016;123:1036-1042
(2) Susan Vitale, Robert D Sperduto, Frederick L Ferris 3rd. Increased prevalence of myopia in the United States between 1971-1972 and 1999-2004. 2009 Dec;127(12):1632-9.
(3) Bullimore M.A., Brennan N.A. Myopia Control: Why Each Diopter Matters. Optom. Vis. Sci. 2019;96:463–465. doi: 10.1097/OPX.0000000000001367
(4) Diagram (a). Image borrowed from: Barry Santini, (n.d.) for 20/20. [Web article]
(5) Diagram (b). Image borrowed from HOYA, 2020.
(6) Diagram (c). Image borrowed from HOYA, 2020.
