An evaluation of visual function during DOT lens wear

Paper title: Visual impact of diffusion optic technology lenses for myopia control

Authors: Wolffsohn JS (1); Hill JS (2); Hunt C (3); Young, Graeme (3)

1. Optometry and Vision Sciences Research Group, Health and Life Sciences, Aston University, Birmingham, UK.

2. SightGlass Vision Inc, Los Altos, California, USA.
3. Visioncare Research Ltd, Farnham, UK.

Date: Sep 2024

References: Wolffsohn JS, Hill JS, Hunt C, Young G. Visual impact of diffusion optic technology lenses for myopia control. Ophthalmic Physiol Opt. 2024 Sep 3

[Link to open access paper]

The CYPRESS study previously established that DOT 0.2 spectacle lenses were effective and safe for reducing myopia progression in young children.¹ The lenses incorporate light scattering optical segments across the lens (sparing a central 5mm zone to verify lens power), dispersing light and reducing retinal contrast.

This study aimed to assess the visual performance of DOT 0.2 lenses for primary gaze and during daily activities, compared to single vision spectacle lenses. Existing participants in the CYPRESS study aged 10-14yrs (mean age 12.2yrs) had been previously randomised across multiple sites to wear either DOT (n = 27) or single vision control spectacle lenses (n = 24), and had worn either their DOT or single vision lenses for at least 3 years.

High and low contrast distance acuities, near acuity, reading speed and stereopsis were all assessed in primary gaze through the central clear 5mm zones. Head position was assessed using artificial intelligence facial feature recognition software.

Non-inferiority margins were calculations for each assessment performed in order to establish a baseline for detectable differences between the DOT and single vision lenses. If the non-inferiority threshold was met, the two lens types were considered to be similar.

• Mean high and low contrast distance acuities and near acuity under glare conditions were similar for DOT and single vision lenses.
• No significant differences were seen between the DOT and single vision lenses for stereopsis, contrast sensitivity, mean reading speed or head position.
• The mean glare scotoma radius for single vision lenses and DOT lenses was 0.50° and 0.56°, respectively. The difference was smaller than the non-inferiority bound of 0.4°.
  
  

DOT spectacle lenses were found to induce a small but acceptable level of haloes, and otherwise demonstrated myopia control efficacy without compromising reading speed, head posture or visual acuities in high and low contrast conditions. The visual acuities achieved with DOT lenses were comparable to those reported in clinical trials of Defocus Incorporated multiple Segments (DIMS) and Highly Aspheric Lenslets (HAL) spectacle lens designs^2,3

The vision quality was shown to be clinically equivalent to a single vision spectacle lens and are unlikely to adversely affect visual quality during wear, making them suitable for children to wear as myopia control spectacle lenses, particularly during their school years.

The DOT lenses had shown slightly better, although non-significant, contrast sensitivity for mid-spatial frequencies compared to the single vision lenses. Further studies could examine if reduced contrast sensitivity in the peripheral retina could encourage peak spatial frequent detection in the central retina.

Limitations to this study include:

• Assessing visual quality in primary gaze. While this may not reflect the typical use of the lenses in normal habitual wear, the children were allowed to move their heads and eyes during testing and there were no differences in head movements between DOT lens and single vision wearing children. Since functional reading and head posture were unaffected by DOT lens wear, this indicates that alignment within the central lens aperture may not be critical for these tasks.  
• Using a parallel-group, rather than a cross-over study design. However, the parallel groups allowed for long-term wear adaptation.

Title: Visual impact of diffusion optic technology lenses for myopia control

Authors: James S Wolffsohn, Jennifer S Hill, Chris Hunt, Graeme Young

Purpose: To assess the visual impact of Diffusion Optics Technology™ 0.2 DOT lenses (SightGlass Vision Inc.) designed for myopia control on primary gaze. DOT spectacle lenses contain light scattering elements that scatter light as it passes through the lens which, in turn, reduces retinal image contrast.

Methods: Fifty-one children (12.2 ± 1.3, range 10-14 years; 51% females) were randomly assigned to wear DOT spectacle (n = 27) or single vision lenses (n = 24) across six investigational sites in North America. Binocular high- and low-contrast distant visual acuities, near visual acuity, reading speed, contrast sensitivity, stereoacuity and glare were assessed in primary gaze after at least 3 years of wear, with the study 95% powered in all metrics to detect significant differences between the groups.

Results: Mean binocular distance high-contrast (-0.09 ± 0.02 vs. -0.08 ± 0.02 logMAR, p = 0.81), low-contrast (0.05 ± 0.02 vs. 0.07 ± 0.02 logMAR, p = 0.52) and near visual acuity with glare sources (-0.06 ± 0.03 vs. -0.09 ± 0.03 logMAR, p = 0.32) were similar for DOT and single vision lens wearers, respectively. Contrast sensitivity was similar between children wearing DOT or single vision lenses across 11 of the 16 spatial frequencies (p > 0.05). Mean stereopsis was similar (p = 0.30) with the DOT lenses (33.2 ± 12.5″) and single vision lenses (38.1 ± 14.2″). Functional reading speed metrics were similar in both study groups, as was the objectively measured head tilt during reading (p > 0.05). The mean halo radius was 0.56° ± 0.17° with the DOT lenses compared with 0.50° ± 0.12° with single vision lenses (p = 0.02), but the statistically significant difference was smaller than the non-inferiority bound of 0.4°.

Conclusions: Diffusion optics technology lenses provide a clinically equivalent visual experience to a standard single vision lens.

[Link to open access paper]