Spectacle Lenses for Myopia: Our Complete Guide
The development of myopia in children and teenagers is of increasing concern worldwide. A range of new technologically advanced lenses with proven effectiveness in clinical trials are designed to slow the rate of myopia progression. For Eyes Optometrist, an Australian-owned independent optometrist in Fremantle can select and advise on the most effective myopia control spectacle lenses based on clinical evidence.
Lenses are a key component of spectacles, and only special designs of spectacle lenses help reduce or slow the progression of myopia in children and teenagers. Single-vision spectacles, whilst inexpensive and convenient, do not help slow the progression of myopia.
Lens Types Available for Myopia Control
Single vision
Bifocal lenses
Multifocal lenses
1. Single Vision Lenses
This is the most prescribed type of spectacle lens. Single-vision lenses can correct both myopia (shortsightedness) and also hyperopia (longsightedness) and (astigmatism). Single-vision lenses are widely available and a cost-effective vision correction, making them popular for correcting various vision problems. Single vision lenses are a fixed focus and single power. A single-focus lens is limiting for older people lacking near-focusing power (presbyopia), where a different lens power is required for near vision.
2. Bifocal Lenses
Bifocals are a spectacle lens with a distance focus at the top and a fixed near focus at the bottom of the lens. It is like having two separate lenses in one. There will be a visible line in the lower portion of the lenses outlining the near portion of the lens.
Children and teenagers sometimes need to wear multifocal or bifocal lenses to help correct eye focusing or coordination problems, which are also known as eye-teaming difficulties.
3. Multifocal Lenses
Provide a range of focusing power across the spectacle lens. Multifocal (or progressive addition lenses P.A.L.) are designed for clear distance vision when looking straight ahead through the distance optical centre of the lens and clear near vision when looking through the lower part of the lens. The lenses are multifocal with a gradual increase in power from the distance to the near optical centres. Multifocal lenses provide clear vision at a range of distances from far to near.
Spectacle Lenses for Myopia Control
New spectacle lens designs are available for myopia control. These designs incorporate either 'lenslet' or 'diffusion' technology.
The Hoya lens manufacturing company uses spectacle lens technology that adopts Defocus Incorporated Multiple Segments (DIMS). The myopia control name for the Hoya spectacle lens is MiYOSMART, where lens lets are incorporated into the lens in a honeycomb array based around a clear central zone. The clear central zone and spaces between the lenslets provide clear, sharp distance vision.
The Essilor lens manufacturing company use spectacle lens technology that uses Highly Aspherical Lenslet Target (or H.A.L.T.) Technology. The myopia control brand name for the spectacle lens is Essilor Stellest. Essilor Stellest lenses feature a series of concentric rings of HALT lenslets based around a clear central zone, with spaces between each ring, for clear, sharp distance vision.
Other myopia control lens designs use Diffusion Optics Technology (or D.O.T.). These spectacle lenses incorporate microscopic diffusers around a smaller, clear central zone. The D.O.T. design creates a diffusion or blur of light around the edges of the lens with clear central vision.
These lens designs create a "slow-down" signal for eye growth to control myopia in the peripheral retina. The clear central zones and spaces between lenslets provide for clear
The Hoya MiYOSMART lens and Essilor Stellest lens are explicitly designed for myopia progression and have been shown to offer high efficacy for myopia control. They rank alongside other successful treatments, such as Ortho-k and contact lenses such as Cooper Vision MiSight contact lenses.
Summary
Myopia management via spectacle lenses has been shown to significantly slow the progression of myopia in children.
Single-vision spectacles, whilst inexpensive and convenient, do not help slow the progression of myopia.
Specialised designs of myopia control spectacle lenses can both correct blurred vision from myopia and work to slow down its progression.
Because of their ease of use, effectiveness, and accessibility, specially designed spectacle lenses remain a key factor in controlling myopia.
For more information on Myopia control and these treatment types, please ask your practitioner at For Eyes Optometrist.
Frequently Asked Questions
Are MiyoSmart and Stellest lenses compatible with any frame?
The size and position of myopia management lenses are key factors in their performance. These lenses are designed with a central clear zone surrounded by a concentric peripheral defocus zone. To ensure their effectiveness, it's essential that the pupil is centrally located in a frame with at least 12 millimetres between the top of the frame and the centre of the pupil. This, along with a vertex distance of 10 millimetres or less and a pantoscopic angle close to zero, plays a significant role in the lenses' performance.
The frame must also fit nicely on a child's face. For example, the fit of the nose bridge and correct temple length ensure the frame is comfortable and does not slip down the child's nose.
At For Eyes Optometrist, we can advise on fit and measure the location of the eye pupil to ensure that the myopia lenses will be effective.
Can myopia lenses be combined with other myopia management strategies?
The potential of combined treatments is attractive and promising, especially when a child is young, at the age of onset, and where myopia is progressing rapidly.
There is good supporting evidence for the effectiveness of combining low-dose atropine with orthokeratology. Currently, clinical trials are lacking to demonstrate the effect of combining myopia-control spectacle lenses with low-dose atropine. However, promising results are starting to be reported in practice (Nucci et al., Combining Spectacle Lenses with Atropine 0.01% in European Children).
Whatever approach is chosen to manage a child's myopia, the options are discussed with parents. This inclusive approach ensures that each case's management plan is customised, making parents and their children feel involved and informed.
Are there any side effects or discomforts associated with wearing myopia controlled lenses?
As with any spectacle lens, there is a period of adaption. However, the majority of children adapt very quickly (within a week or two) to wearing these lenses and do not experience any discomfort.
If anything, the disadvantage relates to the limitation of wearing spectacles for a sporting or active lifestlye. In these cases, there are other alternatives such as contact lenses or Orthokeratology.
