The next generation - DIMS, H.A.L.T. and DOT spectacle lenses for myopia control
In this article:
The newest myopia controlling spectacles can both correct and control myopia as well as contact lens options. Here we investigate.
The newest myopia controlling spectacles can both correct and control myopia as well as the most effective contact lens options. This is a highly appealing prospect for myopia control practice, as spectacles are likely an easier place to start, and not all children are ready or willing to wear contact lenses.
What are DIMS, H.A.L.T. and DOT technology?
The DIMS, H.A.L.T. and DOT spectacle lenses take a step beyond the traditional spectacle to behave more like a myopia controlling contact lens. The benefit of a contact lens is that it moves with the eye, so the same optical profile is provided to the central and peripheral retina regardless of the angle of view. This is easy to imagine in the case of a soft multifocal or myopia controlling contact lens, worn on the eye during the day. In the case of orthokeratology, the treatment is 'fixed' through the overnight corneal profile change.
While of course an eye moves behind a spectacle lens, these new lenses can be thought of as 'behaving more like a myopia controlling contact lens' because when the child looks away from the clear central zone, they are receiving simultaneous in-focus information from the single vision distance correction (falling on the retinal plane) and myopic defocus information (falling somewhere in front of the retinal plane).
Perhaps this is why their myopia control efficacy results are seeming to exceed any of the previous spectacle lens solutions, and equaling that of dual focus soft and orthokeratology contact lenses. Let's go further to understand DIMS, H.A.L.T. and DOT spectacle lenses.
How do they work?
When it comes to the theories of myopia control mechanisms, the long standing contender is the peripheral defocus theory, whereby the peripheral retina receives myopic defocus as a slow-down or stop signal for eye growth. This has been shown in animal models - Earl Smith III is arguably the world's leading researcher in this area and you can read a summary lecture of his from 2010, here.
Defocus Incorporated Multiple Segments (DIMS) - Hoya MiYOSMART
Defocus Incorporated Multiple Segments (DIMS) technology was designed by Hong Kong Polytechnic University. It is described in the clinical trial paper as "compris[ing] a central optical zone (9 mm in diameter) for correcting distance refractive errors, and an annular multiple focal zone with multiple segments (33 mm in diameter) having a relative positive power (+3.50 D). The diameter of each segment is 1.03 mm. This design simultaneously introduces myopic defocus and provides clear vision for the wearer at all viewing distances. There are multiple foci from myopic defocus at a plane in front of the retina, which would be received as blur images on the retina."1
Efficacy (two year study): Around 50% refractive and 60% axial length efficacy in Hong Kong Chinese children, with an absolute effect of 0.44D lower refraction and 0.34mm less axial elongation in DIMS wearers.
Highly Aspherical Lenslet Target (H.A.L.T.) technology - Essilor Stellest™
Essilor Stellest™ is described as comprising Highly Aspherical Lenslet Target or H.A.L.T. technology in this Press Release. The recent publication of the one year clinical trial paper2 describes these spectacle lenses as having "a spherical front surface with 11 concentric rings formed by contiguous aspherical lenslets (diameter of 1.1 mm). The area of the lens without lenslets provides distance correction. The geometry of aspherical lenslets has been calculated to generate a VoMD in front of the retina at any eccentricity, serving as a myopia control signal (figure 1)." The image below is Figure 1 from the open access paper.
A recent publication provided one-year results for an ongoing clinical trial. Chinese children aged 8-13 years with myopia of -0.75D to -4.75D were randomized into either single vision, highly aspherical lenslet (HAL) or slightly aspherical lenslet (SAL) spectacle lenses. After one year, (n=161) myopia progressed -0.81D/0.36mm in SV, -0.48D/0.25mm in SAL and -0.27D/0.13mm in HAL.
Efficacy (one year study): Around a 70% refractive and 60% axial length efficacy for HAL and 40% refractive and 30% axial length efficacy for SAL in Chinese children. This is an absolute effect of 0.54D/0.23mm less myopia for HAL wearers and 0.33D/0.11mm less myopia for SAL wearers.
A research abstract on the two-year clinical trial data has just been released (n=157), indicating that myopia progressed -1.46D/0.69mm in SV, -1.04D/0.51mm in SAL and -0.66D/0.34mm in HAL. In children who wore their lenses every day for at least 12 hours per day, the absolute myopia control effect compared to SV was 0.99D/0.41mm less myopia in HAL and 0.57D/0.26mm less myopia in SAL.
Diffusion Optics Technology (DOT) – SightGlass Vision
Diffusion optics technology (DOT) lenses are a little bit different from DIMS and H.A.L.T. in that they do not use lenslets, but diffusers. What are these diffusers? They are thousands of small elements across the lens, shaped as dots that scatter light onto the retina. The small (around 5mm) central section of the lens does not incorporate these dots, providing clear vision and facilitating lens power verification.
This entirely different approach is based on studies of genetic forms of myopia, which show cellular defects in cone photoreceptors linked to high myopia. These defects are characterized by some cones having dramatically reduced function, while adjacent cones function more normally. As stated in the randomized controlled trial paper, "This observation suggests that abnormal contrast signalling between neighbouring full and empty cones may stimulate axial elongation."3
Figure 1 caption from the open-access paper(Rappon 2022): Contrast hypothesis of myopia and development of DOT lens. X-chromosome opsin gene array for a male with high myopia due to the LVAVA haplotype is shown. (A) OPN1LW gene (pink) with LVAVA exon 3 haplotype and OPN1MW gene (green) with MVVVA exon 3 haplotype. The LVAVA haplotype causes exon three to be skipped in pre-mRNA splicing so only about 6% of the mRNA is full length. (B) L (pink) and M (green) cones have dramatically different photopigment OD because of mis-splicing. S cones are blue. (C) Retina signals high contrast even under uniform white light because of OD differences. Activity of L cones (grey) is low, activity of M and S cones (black) is high. We hypothesised that the constitutive contrast signalling due to photopigment OD differences stimulates axial elongation of the eye and causes myopia. (D) The hypothesis led to the development of a novel spectacle lens (DOT lens) that reduces contrast (left lens) compared with a standard of care lens (right). DOT, diffusion optics technology; OD, optical density.
SightGlass Vision DOT 0.2 lenses have been investigated in a randomized clinical trial of children aged 6 to less than 10 years, with interim 12-month data recently published. The results showed that children wearing the test lens had 0.15mm axial length growth in a year, compared to 0.30mm in the control group, representing a 50% reduction. For children aged 6-7 years, refractive progression was -0.19D in a year in the test lens compared to -0.75D in the control group.3
Efficacy (one-year study): Around 74% refractive and 50% axial length efficacy in North American, multi-ethnic children for the DOT 0.2 lenses, with an absolute effect of 0.40D lower refraction and 0.15mm less axial elongation.3
How do they compare for efficacy?
Currently we have two-year randomized controlled trials published for DIMS and for H.A.L.T. technology, both published as full scientific papers. Both have been conducted with Chinese children aged 8-13 years as participants, and with similar baseline characteristics. Let's compare the 6-month and 12-month results as provided in both studies.1,2
What do you see in those results? Let's compare the control and treatment groups. Keep in mind that we can't do direct statistical tests to see if they are different, so we're looking at the means and standard deviations for similarity or not.
The DOT 0.2 lens, by comparison, has one-year randomized controlled trial published data. This was a multi-site study taking place in North America, recruiting children aged 6 to less than 10 years.3 It is the first data of its type in younger children, which is useful as this age group tends to show fastest myopia progression.7 The myopia control effects were 0.40D and 0.15mm less progression over a year; again around a 50% efficacy for slowing axial eye growth.3 A three-year clinical trial for this lens has been completed but is yet to be published as a full scientific paper.
Once two-year data is available for the DOT 0.2 lens, the comparison can be made more robustly. As recent analysis has explained, percentages must be carefully applied only to the duration of the study and not extrapolated further, as percentage treatment effect can change over time.8 So watch this space, for more comparison data.
Read more on spectacle lenses for myopia control
Meet the Authors:
About Kate Gifford
Dr Kate Gifford is a clinical optometrist, researcher, peer educator and professional leader from Brisbane, Australia, and a co-founder of Myopia Profile.
- Lam CSY, Tang WC, Tse DY, Lee RPK, Chun RKM, Hasegawa K, Qi H, Hatanaka T, To CH. Defocus Incorporated Multiple Segments (DIMS) spectacle lenses slow myopia progression: a 2-year randomised clinical trial. Br J Ophthalmol. 2020 Mar;104(3):363-368. (link)
- Bao J, Yang A, Huang Y, Li X, Pan Y, Ding C, Lim EW, Zheng J, Spiegel DP, Drobe B, Lu F, Chen H. One-year myopia control efficacy of spectacle lenses with aspherical lenslets. Br J Ophthalmol. 2021:318367. (link)
- Rappon J, Chung C, Young G, Hunt C, Neitz J, Neitz M, Chalberg T. Control of myopia using diffusion optics spectacle lenses: 12-month results of a randomised controlled, efficacy and safety study (CYPRESS). Br J Ophthalmol. 2022 Sep 1:bjophthalmol-2021-321005. (link)
- Neitz M, Patterson SS, Neitz J. Photopigment genes, cones, and color update: disrupting the splicing code causes a diverse array of vision disorders. Curr Opin Behav Sci. 2019 Dec;30:60-66. (link)
- Wolffsohn JS, Kollbaum PS, Berntsen DA, Atchison DA, Benavente A, Bradley A, Buckhurst H, Collins M, Fujikado T, Hiraoka T, Hirota M, Jones D, Logan NS, Lundstrom L, Torii H, Read SA, Naidoo K. IMI - Clinical Myopia Control Trials and Instrumentation Report. Invest Ophthalmol Vis Sci. 2019;60(3):M132-M160. (link)
- Brennan NA, Toubouti YM, Cheng X, Bullimore MA. Efficacy in myopia control. Prog Retin Eye Res. 2020 Nov 27:100923. (link) [Link to Myopia Profile paper review]
- Tricard D, Marillet S, Ingrand P, Bullimore MA, Bourne RRA, Leveziel N. Progression of myopia in children and teenagers: a nationwide longitudinal study. Br J Ophthalmol. 2021 Mar 12:bjophthalmol-2020-318256. (link)
- Brennan NA, Toubouti YM, Cheng X, Bullimore MA. Efficacy in myopia control. Prog Retin Eye Res. 2020 Nov 27:100923. (link)
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