Modelling the refractive and imaging impact of multi‐zone lenses utilised for myopia control in children’s eyes

Sah, Raman Prasad; Jaskulski, Matt; Kollbaum, Pete

doi:10.1111/opo.12959

Cited by 9 publications

(8 citation statements)

References 57 publications

(143 reference statements)

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“…Finally, our participants had unnaturally large (pharmacologically dilated) pupils (mean diameter = 7.2 mm), which may affect which component of the dual focus lens was dominant at a particular eccentricity. 45 Nonetheless, despite these limitations, our results show that the inner and outer retina can respond uniquely to different levels of simultaneously applied defocus, primarily within the central 10°. The peak difference in the retinal responses when exposed to dual focus is near the 2.00D myopic defocus that is commonly used for myopia control.…”

Section: Discussionmentioning

confidence: 67%

Dual‐focus contact lenses for myopia control modify central retinal electrophysiology in humans

Turnbull

Goodman

Phillips

2023

Ophthalmic Physiologic Optic

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IntroductionDual‐focus contact lenses create two focal planes, one providing a clear retinal image while the other imposes myopic defocus on the retina to slow myopia progression. This study used global‐flash multifocal electroretinogram (gmfERG) response amplitudes to compare central versus peripheral retinal responses under dual‐focus conditions and to assess the optimal degree of myopic defocus compared with a single‐vision control lens.MethodsTwenty participants each underwent three gmfERG trials, wearing a spectacle correction over dual‐focus contact lenses with plano central power and peripheral secondary focal powers of either +2.00D, +4.00D or a plano single‐vision lens. We compared amplitudes and latencies of the gmfERG direct and induced components (DC and IC) within participants, between the three different contact lens powers and at different retinal eccentricities (gmfERG ring).ResultsWe observed significant differences in the gmfERG responses between the single‐vision and dual‐focus contact lenses. Overall, DC amplitudes peaked between zero and +2.00D secondary power, while IC amplitudes were maximal between +2.00D and +4.00D. Compared with the single‐vision control, the greatest increase in DC and IC amplitudes while wearing dual‐focus lenses occurred within the central 10° of the retina. There was no interaction effect between gmfERG ring (eccentricity) and secondary power, and no difference in the latency of the gmfERG responses between different powers.ConclusionWe found that dual‐focus contact lenses with a +2.00D secondary power are close to that expected to induce the greatest increase in gmfERG responses relative to a single‐vision lens. Dual‐focus lenses produced the highest DC and IC response amplitudes relative to a single‐vision lens in the central 10° of the retina. This suggests that dual‐focus contact lenses slow myopia progression by modifying central rather than peripheral retinal activity.

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Section: Discussionmentioning

confidence: 67%

Dual‐focus contact lenses for myopia control modify central retinal electrophysiology in humans

Turnbull

Goodman

Phillips

2023

Ophthalmic Physiologic Optic

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“…This is also likely an artefact of instrument sampling resolution, as well as the inability of our method to appropriately quantify refractive state at the pupil centre (e.g., where ‘ r ’ approaches zero and wavefront slope is a finite value [see Equation ]). The observed decrease in myopic defocus at higher target vergences is likely a result of the commonly seen accommodative lag and negative spherical aberration induced due to accommodation, the combined effects of which have been shown to reduce the effective myopic defocus dose power in the treatment zones of multi‐zone lenses 20 …”

Section: Discussionmentioning

confidence: 99%

“…The observed decrease in myopic defocus at higher target vergences is likely a result of the commonly seen accommodative lag and negative spherical aberration induced due to accommodation, the combined effects of which have been shown to reduce the effective myopic defocus dose power in the treatment zones of multi-zone lenses. 20…”

Section: Multi-zone Contact Lenses and The Defocus Induced In Treatme...mentioning

confidence: 99%

“…The reported efficacy of multi-zone contact lenses, compared with SV lenses over a period of 1-3 years, ranged from 0.21 to 0.67 D less progression when comparing cycloplegic refraction and 0.11-0.28 mm less axial elongation with multi-zone contact lenses. 8,10,13,15,17,18 Several optical factors have been proposed to account for this varying range of efficacy, 19 including the following: (a) contact lens optical design and/ or zone geometry, 20 (b) accuracy of accommodation 21,22 and (c) anatomical factors such as the magnitude of myopia and axial length of the eye. 23 The current study examined the impact of multi-zone contact lens zone geometry on the induced myopic defocus for a range of viewing conditions.…”

Section: Introductionmentioning

confidence: 99%

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Impact of zone geometry on the introduction of myopic defocus in young adult eyes wearing multi‐zone lenses

Sah

Meyer

Jaskulski

et al. 2023

Ophthalmic Physiologic Optic

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PurposeMultizone contact lenses control myopia progression by proposed introduction of myopic defocus. This project investigated how much of the pupil area and how many dioptres of myopic defocus are introduced by different lens zone geometries with near‐ and off‐axis viewing.MethodsTen young myopic adults (18–25 years) binocularly wore four soft contact lenses including a single vision (SV), concentric‐ring dual‐focus (DF), centre‐distance multifocal (MF) and a RingBoost™ (RB) multi‐zone design containing a combination of coaxial and non‐coaxial zones. A modified aberrometer captured aberrations and pupil sizes at four target vergences between −0.25 and −4.00 D (on‐axis) and across the central ±30° of the horizontal retina (off‐axis). Defocus was quantified as the difference between the measured refractive state and the target vergence within each zone of a multi‐zone design within the pupil and compared with that of equivalent zone areas of the SV lens. The percentage of the pupil containing myopic defocused light for each lens was calculated.ResultsDefocus within the distance correction zones of multi‐zone lenses was similar to that of the SV lens. When viewing on‐axis at −0.25 D target vergence, on average 11% of the pupil was myopic with SV, whereas 62%, 84% and 50% of the pupil was myopic for the DF, MF and RB designs, respectively. At −4.00 D target vergence, all lenses exhibited a systematic decrease in the percentage of pupil area having myopic defocus (SV: 3%; DF: 18%; MF: 5% and RB: 26%). The off‐axis proportions were similar across multi‐zone lenses; however, multi‐zone lenses retained approximately 1.25–3.0× more myopic defocus than the SV lens.ConclusionsSubjects accommodated using the distance‐correction zones of multi‐zone lenses. Multi‐zone contact lenses introduced significant myopic defocus on‐axis and across the central ±30° retina. However, the magnitude and proportion of defocus were influenced by zone geometry, add power and pupil size.

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“…Previous efforts to characterise the imaging properties are based-on wavefront measurements and on-axis illumination 3,4 . However, this approach is prone to show limitations for: i. assuring the fidelity of phase maps retrieved from spectacle lens based on micro-diffusion technology; and ii.…”

Section: Introductionmentioning

confidence: 99%

Optical characterisation of spectacle lenses for myopia control

Gallego¹,

Ohlendorf²,

Artal³

et al. 2023

Ophthalmic Technologies XXXIII

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Myopia is the most common ocular disorder worldwide and the leading cause of visual impairment in children. Its progression affects the normal retinal development, increasing the risk of suffering severe ocular pathologies that lead to irreversible blindness. Although the mechanism for myopia progression is not completely elucidated yet, it is suggested that the quality of the peripheral retinal images may play a role. This produced an enormous interest in using spectacle lenses with different focusing properties for foveal and peripheral vision as a treatment to slow myopia progression. In this work, we developed a novel instrument to optically characterise spectacle lenses designed for myopia control under realistic viewing conditions. First, the testing beam impinges the spectacle under test with different eccentricities. For each eccentricity, a steering mirror guides the beam towards a liquid crystal spatial light modulator (SLM). The SLM allows for reproducing several pupil sizes, shaping the pupil according to the eccentricity, reproducing ocular aberrations for different levels of myopia, and acquiring the through-focus point spread functions (PSFs). An electrically tunable liquid lens, conjugated to the SLM, compensates the base power of the tested lens and focuses the beam into a camera’s sensor. Three spectacle lenses were tested, and different optical metrics were calculated from the PSF and the modulation transfer function.

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Modelling the refractive and imaging impact of multi‐zone lenses utilised for myopia control in children’s eyes

Cited by 9 publications

References 57 publications

Dual‐focus contact lenses for myopia control modify central retinal electrophysiology in humans

Dual‐focus contact lenses for myopia control modify central retinal electrophysiology in humans

Impact of zone geometry on the introduction of myopic defocus in young adult eyes wearing multi‐zone lenses

Optical characterisation of spectacle lenses for myopia control

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