Optical Characterization of a Diffusion Optics Technology Ophthalmic Lens designed for myopia control

Abstract

Purpose : Novel spectacle lenses from SightGlass Vision^TM utilize Diffusion Optics Technology™ (DOT) to slow myopia progression by modulating contrast at the retina. These lenses contain a clear central area encircled by a treatment zone with light scattering micro-dots. Here, we evaluated the imaging properties of DOT lenses by optically measuring the Point Spread Function (PSF) followed by computing the modulation transfer function (MTF).

Methods : The PSF of a DOT lens was acquired from 10 different regions within the treatment zone and the clear central zone was used as a reference. The PSFs were measured using a custom-built 4f optical imaging system with a 636.8 nm laser diode and an 8 mm pupil. A CMOS sensor (Sony^TM Exmor 1/2.3’) with a 1.55 um pitch and 12-bit digital output was used to capture the image of the PSF from which the MTF was computed. Relative image quality was assessed in each zone by dividing the area under the MTF curve (AUC) of the treatment zone by the clear central zone.

Results : Sharp PSF’s are seen through the DOT treatment area, resembling those seen through the clear central zone. Modulation values across the 10 areas within the treatment zone describe a similar trend over most of the spatial frequencies (SFs) (Figure 1). When comparing to the central clear zone, the DOT treatment areas demonstrated minimal contrast reduction at low frequencies (<18 cycles per degree (cpd)), however, some slight contrast reduction is observed for very high SFs (>30 cpd). At clinically relevant contrast sensitivity SFs of 3, 6, 12, and 18 cpd, the mean modulation values across the 10 regions covered by the micro-dots were similar to that of the clear central zone (Table 1).

Conclusions : The PSF-imaging method and MTF analysis reveals that DOT lens design can generate comparable image quality and visual performance to SV lenses when looking through the treatment zone, up to 18 cycles per degree. However, some reduction is present at higher SFs toward the upper detectable limits of human vision. This finding suggests that contrast reduction introduced by the micro-dots in the DOT lens does not limit its ability to provide high quality spatial details and good visual performance.

This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.

 

Figure 1.- MTFs curves by zone.

 

Table 1.- Modulation values at 3, 6, 12, and 18 cycles per degree per zone of a DOT spectacle lens.