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PURPOSE High sampling density optical metrology combined with pupil- and image-plane numerical analyses were applied to evaluate a novel spectacle lens containing multiple small zones designed to slow myopia progression. METHODS High-resolution aberrometry (ClearWave, www.lumetrics.com) was used to sample wavefront slopes of a novel spectacle lens, Defocus Incorporated Multiple Segments (DIMS) (www.hoya.com), incorporating many small, positive-powered lenslets in its periphery. Using wavefront slope and error maps, custom MATLAB software ('Indiana Wavefront Analyzer') was used to compute image-plane point-spread functions (PSF), modulation transfer functions (MTF), simulated images and power distributions created by the dual-focus optic for different pupil sizes and target vergences. RESULTS Outside of a central 10 mm zone containing single distance optical power, a hexagonal array of small 1 mm lenslets with nearest-neighbour separations of 0.5 mm were distributed over the lens periphery. Sagittal and curvature-based measures of optical power imperfectly captured the consistent +3.50 D add produced by the lenslets. Image plane simulations revealed multiple PSFs and poor image quality at the lenslet focal plane. Blur at the distance optic focal plane was consistent with a combination of diffraction blur from the distance optic and the approximately +3.50 D of defocus from the 1 mm diameter near optic zones. CONCLUSION Converging the defocused beams generated by the multiple small (1 mm diameter) lenslets to a blurred image at the distance focal plane produced a blur magnitude determined by the small lenslet diameter and not the overall pupil diameter. The distance optic located in between the near-add lenslets determines the limits of the optical quality achievable by the lens. When compared to the optics of a traditional concentric-zone dual-focus contact lens, the optics of the DIMS lens generates higher-contrast images at low spatial frequencies (

To develop an optical model of a child's eye to reveal the impact of target distance and accommodative behaviour on retinal image quality when fitted with multi-zone lenses.Pupil size, aberration levels and accommodative lag were adjusted for models viewing stimuli at 400, 100, 33 and 20 cm. Distributions of defocus across the pupil and simulated retinal images were obtained. An equivalent 16-point letter was imaged at near viewing distances, while a 0.00 logMAR (6/6) letter was imaged at 400 cm. Multi-zone lenses included those clinically utilised for myopia control (e.g., dual-focus, multi-segmented and aspherical optics).Viewing distance adjustments to model spherical aberration (SA) and pupil radius resulted in a model eye with wider defocus distributions at closer viewing distances, especially at 20 cm. The increasing negative SA at near reduced the effective add power of dual-focus lenses, reducing the amount of myopic defocus introduced by the centre-distance, 2-zone design. The negative SA at near largely compensated for the high positive SA introduced by the aspheric lens, removing most myopic defocus when viewing at near. A 0.50 D accommodative lag had little impact on the legibility of typical text (16-point) at the closer viewing distances.All four multi-zone lenses successfully generated myopic defocus at greater viewing distances, but two failed to introduce significant amounts of myopic defocus at the nearest viewing distance due to the combined effects of pupil miosis and negative SA. Typical 16-point type is easily legible at near even in presence of the multi-zone optics of lenses utilised for myopia control and accommodative lag.

PURPOSE To evaluate the refractive impact of dual-focus (DF) myopia control contact lenses (CLs) on accommodating young myopic adults. METHODS Phase 1: accommodative accuracy was assessed in 40 myopic participants. Phase 2: a subset of four subjects who demonstrated accurate accommodation and six who chronically underaccommodated were fitted with single vision (SV, Proclear 1 day) and centre-distance DF myopia control CLs (MiSight 1 day) with approximately +2.00 D of additional power in two surrounding annular zones. While binocularly viewing high contrast characters at 4.00, 1.00, 0.50, 0.33, 0.25 and 0.20 m, aberrometry data were captured across the central ±30° of the horizontal retina. Local refractive errors were pooled for each area of the pupil covered by the central distance or first annular defocus zone of the DF CLs. RESULTS In the "good" accommodator group fitted with SV CLs, accommodative lags were generally absent except at the closest viewing distance (mean errors: -0.09 ± 0.22 D, -0.12 ± 0.26 D, -0.05 ± 0.37 D and +0.38 ± 0.54 D for -2.00, -3.00, -4.00 and -5.00 D target vergences, respectively) but significantly larger in the "poor" accommodating participants (+0.81 ± 0.21 D, +0.97 ± 0.27 D, +1.18 ± 0.39 D, +1.47 ± 0.55 D). For most viewing distances, hyperopic defocus observed in the region of the pupil covered by the first annular zone was replaced with myopic defocus when fitted with the DF CLs. Myopic defocus created by the first annular region was present across the central 30° of the retina. CONCLUSIONS Some young adult myopes chronically experience high levels of hyperopic defocus when viewing near targets, which was replaced by myopic defocus in the annular part of the pupil covered by the treatment zones when fitted with a centre-distance myopia control DF CL.

Significance Measurement of ocular aberrations is a critical component of many optical corrections. Purpose This study examines the accuracy and repeatability of a newly available high-resolution pyramidal wavefront sensor-based aberrometer (Osiris by Costruzione Strumenti Oftalmici, Firenze, Italy). Methods An engineered model eye and a dilated presbyopic eye were used to assess accuracy and repeatability of aberration measurements after systematic introduction of lower- and higher-order aberrations with calibrated trial lenses (sphere +10.00 to -10.00 D, and astigmatic -4.00 and -2.00 D with axis 180, 90, and 45°) and phase plates (-0.57 to 0.60 μm of Seidel spherical aberration defined over a 6-mm pupil diameter). Osiris aberration measurements were compared with those acquired on a previously calibrated COAS-HD aberrometer for foveal and peripheral optics both with and without multizone dual-focus contact lenses. The impact of simulated axial and lateral misalignment was evaluated. Results Root-mean-square errors for paraxial sphere (corneal plane), cylinder, and axis were, respectively, 0.07, 0.11 D, and 1.8° for the engineered model and 0.15, 0.26 D, and 2.7° for the presbyopic eye. Repeatability estimates (i.e., standard deviation of 10 repeat measures) for the model and presbyopic eyes were 0.026 and 0.039 D for spherical error. Root-mean-square errors of 0.01 and 0.02 μm, respectively, were observed for primary spherical aberration and horizontal coma (model eye). Foveal and peripheral measures of higher- and lower-order aberrations measured with the Osiris closely matched parallel data collected with the COAS-HD aberrometer both with and without dual-focus zonal bifocal contact lenses. Operator errors of focus and alignment introduced changes of 0.018 and 0.02 D/mm in sphere estimates. Conclusions The newly available clinical pyramidal aberrometer provided accurate and repeatable measures of lower- and higher-order aberrations, even in the challenging but clinically important cases of peripheral retina and multifocal optics.

A combination of human subject data and optical modelling was used to investigate unexpected nasal-temporal asymmetry in peripheral refraction with an aspheric myopia control lens. Peripheral refraction was measured with an auto-refractor and an aberrometer. Peripheral refraction with the lens was highly dependent upon instrument and method (e.g. pupil size and the number of aberration orders). A model that did not account for on-eye conformation did not mirror the clinical results, but a model assuming complete lens conformation to the anterior corneal topography accounted for the positive shift in clinically measured refraction at larger nasal field angles. The findings indicate that peripheral refraction of highly aspheric contact lenses is dependent on lens conformation and the method of measurement. These measurement methods must be reported, and care must be used in interpreting results.

Purpose To compare the visually weighted image quality and depth of focus achieved with small-pupil and multifocal strategies for expanding depth of focus of presbyopic or pseudophakic eyes. Setting School of Optometry, Indiana University, Bloomington, USA. Design Computational modeling. Methods The visual Strehl ratio was computed from monochromatic optical transfer functions over a wide range of primary spherical aberration and defocus levels for pupil diameters ranging from 1.0 mm to 7.0 mm under high photopic light levels (retinal illuminance >900 trolands) and mesopic light levels (2 candelas/m2). Results Pupil miosis and added spherical aberration were effective at reducing the impact of spherical defocus. With high light levels at which Weber's law makes neural contrast sensitivity independent of retinal illuminance, small pupils (eg, 1.0 to 3.0 mm) generated higher peak image quality and more effective expansion of depth of focus than the small-pupil multifocal model. However, under low light levels at which the reduced retinal illuminance associated with pupil miosis lowered neural contrast sensitivity, the peak image quality was lower with small pupils (1.0 to 1.5 mm) at all aberration levels. Large pupils and high levels of spherical aberration were most effective at expanding the depth of focus under mesopic light levels. Conclusions When reductions in retinal illuminance created by pupil miosis have no effect on neural contrast sensitivity, small pupils produced higher image quality and larger depth of focus than multifocal optics and large pupils. In general, the reverse was true under mesopic light conditions.