David Atchison

• Queensland University of Technology

Purpose To provide a more sophisticated explanation of the optics involved when retinal ‘shadows’ are seen in scanning laser ophthalmoscopic images during the wear of multisegment and diffusion optic spectacle lenses. Methods Images were recorded with a system that uses a scanning broad line fundus imaging principle in participants with undilated...

This study presents a method for retinal reconstruction using peripheral biometry. The incident beam is presumed to be directed toward the center of curvature of the anterior cornea, reaching the retina with minimal deviation. A significant advancement is demonstrated by extending previous approaches to three dimensions and effectively capturing th...

Purpose Part 1 of the study investigated image quality associated with oblique incidence of light on a multisegment lens (Hoya MiyoSmart) intended to treat myopia development. Part 2 investigates power corrections associated with oblique incidence. Methods Modelling and ray tracing were carried out with lenses of −4 D distance power and, to a less...

Purpose To describe patterns of peripheral refraction based on spherical equivalent refraction and on tangential and sagittal refractions, and to assess the association of peripheral refraction patterns with different central refractions. Methods Peripheral refraction data from 737 individuals (14.7 ± 5.1 years old) were analyzed. Peripheral refra...

Introduction Multisegment (MS) spectacles are intended to slow myopia progression by modifying images falling on the peripheral retina. Some published optical treatments of these lenses assume normal incidence of light at the surfaces, but images falling on the peripheral retina are usually associated with oblique ray pencils. Here, we model repres...

Purpose To investigate the influence of the corneal epithelium on corneal power, particularly in special cases such as post‐refractive surgery and keratoconus. Methods A retrospective observational study. Measurement data were obtained from a high‐resolution anterior segment analyser (CSO MS‐39). Corneal curvature and power data, as well as surfac...

The field of visual and physiological optics is undergoing continuous significant advancements, driven by a deeper understanding of the human visual system and the development of cutting-edge optical technologies. This Roadmap, authored by leading experts, delves into critical areas such as corneal biomechanical properties, keratoconus, and advance...

Purpose: To investigate the longitudinal relationship between myopia and retinal shape in Chinese children. Methods: A total of 2471 seven-year-old Chinese children were measured for axial length, anterior corneal radius of curvature, anterior chamber depth, lens thickness, central spherical equivalent, and peripheral refractions along the horiz...

Purpose: The purpose of this study was to assess fine motor skills and reading proficiency in adults with amblyopia and/or strabismus, and to determine how these relate to clinical measures of vision and self-reported vision-related quality of life. Methods: Fine motor skills (Manual dexterity - Bruininks-Oseretsky Test of Motor Proficiency [BOT...

Aim To develop an accommodating, wide‐angle, schematic eye for emmetropia and myopia in which spectacle refraction and accommodation level are input parameters. Method The schematic eye is based on an earlier unaccommodated refraction‐dependent eye for myopia developed by Atchison in 2006. This has a parabolic gradient index lens and parameters de...

Purpose To discuss factors influencing corneal aberrations that might influence the optical quality after intraocular lens (IOL) implantation. Methods PubMed and Scopus were the main resources used to search the medical literature. An extensive search was performed to identify relevant articles concerning factors influencing the level of corneal a...

SIGNIFICANCE This is a review of the optics of various spectacle lenses that have been used in myopia control over the last 60 years, with emphasis on approximately the last 15 years. Myopia has become an increasing health problem worldwide, particularly in some East Asian countries. This has led to many attempts to slow its progression in children...

Purpose This study compared in vivo crystalline lens shape measurements using B‐scan images from the IOLMaster 700 with phakometry. Methods Twenty‐four young adult participants underwent IOLMaster 700 and phakometry measurements under cycloplegia (1% cyclopentolate). The IOLMaster 700 generated B‐scan images along six meridians in 30° increments,...

This study considered two questions associated with intraocular lens (IOL) power and refraction: (1) Given a refraction with a particular IOL in the eye, what will be the refraction for the IOL or another IOL if located differently with regard to tilt or anterior–posterior position? (2) For a target refraction, what is the power of another IOL if l...

Clinical relevance: Understanding devices used for vision screening, including their potential utilisation and validity, will facilitate proper utilisation of this technology. Background: The Acuidrive is a self-illuminated, hand-held, visual acuity screening device intended for use in policing, with visual acuity assessed roadside to identify d...

The pinhole effect is commonly used to discriminate uncorrected refractive error from ocular diseases. A small aperture limits the width of light beams entering the eye, thus increasing the depth of focus. The pinhole effect has also been used in spectacles, contact lenses, corneal inlays, and intraocular lenses (IOLs) to improve reading by compens...

A thin lens technique was developed to determine how the effective powers of toric monofocal intraocular lenses (IOLs) are influenced by tilt and the refractive errors associated with the tilt. A series of steps determined the effective power of the cornea at the IOL, the IOL power, the effective power of the tilted IOL, the correction required at...

Purpose To analyse ocular coherence tomography (OCT) images of the retinal shadows caused by defocus and diffusion optics spectacles. Methods One eye was fitted successively with the Hoya Defocus Incorporated Multiple Segments (DIMS) spectacle lens, two variations of the +3.50 D peripheral add spectacle (DEFOCUS) and the low‐contrast dot lens (Dif...

Retinal image quality decreases with increasing diabetes duration and HbA1c. Eye models with individual phase plates determined optimal pupil size which improved retinal contrast and resolution in those with diabetes by up to 4 times.

Clinical relevance: Binocular visual acuity is an important index of functional performance. Optometrists need to know how binocular visual acuity is affected by aniseikonia, and whether reduced binocular visual acuity is a marker for aniseikonia. Background: Aniseikonia, the perception of unequal image sizes between the eyes, can occur spontane...

Purpose: To apply a theoretical approach to determining how specified IOL powers should change when vitreous oil substitution is combined with IOL implantation. Settings: University laboratory, private Ophthalmological practice. Design: Theoretical raytracing. Methods: Raytracing was done backwards from the retina with equi-convex 20 D and 2...

The study purpose was to improve understanding of how multifocal spectacle lenses affect accommodative errors and whether this changes over time. Fifty-two myopes aged 18 to 27 years were allocated randomly to one of two progressive addition lens (PAL) types with 1.50 D additions and different horizontal power gradients across the near-periphery bo...

Purpose To give an overview of the misconceptions and potential artefacts associated with measuring peripheral refractive error and eye length, the use of these measures to determine the retinal shape and their links to myopia development. Several issues were identified: the relationship between peripheral refractive error and myopia development, i...

Purpose Eye length increases during accommodation, both on‐axis and in the periphery. The aim of this study was to determine whether the peripheral choroid thins with accommodation and to determine the relationship with eye length changes measured at the same location. Methods Subjects included 53 young adults in good ocular and general health, wi...

Significance: Our findings suggest that retinal shapes of the eyes of anisometropes are not different from that of the eyes of isometropes with the same refractions. Purpose: We investigated ( a ) intereye differences in relative peripheral eye lengths between isometropes and anisometropes and ( b ) if the retinal shape is different between isom...

This study compared on-axis and peripheral detection acuities measured with interference fringes, that bypass eye optics, and with screen-based Gabor gratings combined with an adaptive optics system. Gabor gratings are sinusoidal gratings incorporated with a Gaussian envelope that attenuate spatial frequency broadening that occur at the window edge...

In their pioneering work demonstrating measurement and full correction of the eye’s optical aberrations, Liang, Williams and Miller, [JOSA A 14, 2884 (1997)10.1364/JOSAA.14.002884] showed improvement in visual performance using adaptive optics (AO). Since then, AO visual simulators have been developed to explore the spatial limits to human vision a...

Importance Myopia in school-aged children is a public health issue worldwide; consequently, effective interventions to prevent onset and progression are required. Objective To investigate whether SMS text messages to parents increase light exposure and time outdoors in school-aged children and provide effective myopia control. Design, Setting, an...

Light field cameras show great potential for use in retinal imaging. The ability to refocus images and remove glare post-acquisition provides great benefits over current fundus cameras. Previous light field fundus cameras did not have the spatial resolution required for retinal screening. In this work, we design a light field fundus camera based on...

Purpose To determine whether accommodative errors in emmetropes and myopes are systematically different, and the effect of using different instruments and metrics. Methods Seventy‐six adults aged 18–27 years comprising 24 emmetropes (spherical equivalent refraction of the dominant eye +0.04 ± 0.03 D) and 52 myopes (−2.73 ± 0.22 D) were included. A...

Purpose: The purpose of this study was to determine whether accommodation-induced changes in ciliary muscle dimensions vary between emmetropes and myopes, and the effect of the image analysis method. Methods: Seventy adults aged 18 to 27 years consisted of 25 people with emmetropia (spherical equivalent refraction [SER] +0.21 ± 0.36 diopters [D]...

Purpose Red signals signify danger in a range of situations, including train operations. Importantly, misperception of a red signal as yellow can have serious safety implications. This study investigated the effects of lens blur on incorrect colour perception of red signals, which has been implicated in previous train crashes. Methods Participants...

Purpose To develop a paraxial eye model based on a previously collected cohort of adults with well-controlled type 1 diabetes mellitus (DM1) and a limited range of refractive errors. Methods The study used the previously published biometric data of 72 participants (Age: 41.5 ± 12.4 years) with DM1. Measurements included objective refraction, anter...

Purpose To simulate both lens‐induced and screen‐induced aniseikonia, and to assess its influence on stereopsis. Additionally, to determine if screen‐based size differences could neutralise the effects of lens‐induced aniseikonia. Method A four‐circle (4‐C) paradigm was developed, where one circle appears in front or behind the others because of c...

Purpose Multifocal soft contact lenses (MFCLs) are prescribed to inhibit myopia progression; these include aspheric and concentric designs. The effects of MFCLs on visual quality, accommodation and vergence in young-adult myopes were evaluated. Methods Participants were twenty-six myopes (19–25 years, spherical equivalent −0.50 to −5.75D), with no...

Purpose: To explore the relationship of color vision deficiency with myopia progression and axial elongation in Chinese primary school children during a five-year cohort study. Methods: A total of 2849 grade 1 students (aged 7.1 ± 0.4 years) from 11 primary schools were enrolled and followed up for five years. Cycloplegic autorefraction and axia...

Purpose To determine, through simulations, the effect of lateral misalignment of the Grand‐Seiko WR‐5100K autorefractor on peripheral refraction. Methods Using a Navarro schematic eye, into‐ and out‐of‐the eye raytracing was done for a Grand‐Seiko autorefractor simulation. For comparison, conventional out‐of‐the eye raytracing simulated the use of...

Introduction: To investigate the risk factors for myopia progression in primary school children and build prediction models by applying machine learning to longitudinal, cycloplegic autorefraction data. Methods: A total of 2740 children from grade 1 to grade 6 were examined annually over a period of 5 years. Myopia progression was determined as...

Purpose: To determine the annual incidences and rates of progression of myopia and high myopia in Chinese schoolchildren from grade 1 to grade 6 and explore the possible cause-specific risk factors for myopia. Methods: From 11 randomly selected primary schools in Anyang city, central China, 2835 grade 1 students were examined with annual follow...

Purpose To study the optical principles and properties of autorefractors that use the image‐size principle in which the size of the reimaged retinal image determines refraction. Methods The retinal illumination and reimaging of the retinal image were described, as were variations in the basic system. Imaging was determined for systems in which the...

Purpose To determine, through simulations, the likely validity of Grand‐Seiko autorefractors with annular targets in peripheral refraction. Methods Using a physical model eye, the distance inside the eye to which the Grand Seiko AutoRef/Keratometer WAM‐5500 beam was converging and the effective size of its outer diameter at the cornea were determi...

Purpose Human peripheral detection performance is affected by optical factors such as defocus and higher order aberrations. From optical theory, we would expect defocus to produce local depressions (notches) in the contrast sensitivity function (CSF). However, such notches have not been observed in peripheral vision, and it is unknown whether human...

Significance: Anterior eye shape measurements are important for clinical contact lens fitting. The detailed assessment of measurement repeatability using the Eye Surface Profiler (ESP; Eaglet Eye B.V., AP Houten, the Netherlands) allows for more reliable interpretation of eye surface topography measurements. Purpose: This study aimed to determin...

Purpose Prolonged nearwork has been implicated in myopia progression. Accommodation responses of young‐adult myopes wearing different multifocal contact lenses were compared. Methods Twenty adults, 18–25 years, with myopia (spherical equivalent refraction −0.50 to −5.50 D, mean −2.1 ± 1.6 D) wore five lens types in random order: Proclear single vi...

Purpose To measure the Stiles‐Crawford effect of the first kind (SCE‐I), corresponding to central vision, with innovative technology to evaluate changes in the directionality and photoreceptor alignment with accommodation. Methods A uniaxial Maxwellian system (spot size in pupil 0.5 mm diameter) was employed, incorporating a spatial light modulato...

Purpose Approaches are developed to determine relative retinal magnifications in anisometropic patients undergoing cataract surgery; these can be used to balance between full spectacle corrections with equal intraocular lens (IOL) powers and a pure IOL power correction. Methods The analysis started from the original and pseudophakic Navarro eye mo...

The Stiles-Crawford effect of the first kind (SCE) is the phenomenon in which light entering the eye near the center of the pupil appears brighter than light entering near the edge. Previous investigations have found an increase in the directionality (steepness) of the effect as the testing location moves from the center of the visual field to para...

Cataract-induced refractive change (CIRC) is the change in refraction induced by a cataract. It can amount to several diopters (D). It alters predicted errors in refraction following cataract surgery through changes in axial length measurement. This study determined the effect of CIRC on the accuracy of intraocular lens power formula predictions of...

Purpose To quantify the effect of a single scleral lens design on visual acuity and ocular higher‐order aberrations in eyes with post–LASIK ectasia, keratoconus and pellucid marginal degeneration (PMD) that could not achieve satisfactory vision with spectacles or soft contact lenses. Methods Forty‐six eyes of 28 participants fitted with diagnostic...

Third‐order equations are well known for determining sagittal and tangential powers of a thin lens, corresponding to an eye rotating behind a lens to view objects away from the optical axis of the lens. These equations are referenced to the back surface of the lens and do not take into account the peripheral thickness of the lens. They do not give...

Purpose Convergence plays a fundamental role in the performance of near visual tasks. We measured the effect of two levels of convergence on anterior scleral thickness and shape in emmetropes, low to moderate myopes and high myopes. Methods Forty-five healthy young adults aged between 18 and 35 years including 15 emmetropes, 15 low/moderate myopes...

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. p...

We introduce the digital holographic microscope for recording in vivo human eye retinal structures. Current eye imaging technologies cannot provide images with resolutions better than 1 µm within depths of a few hundred micrometers. This can be improved with digital holography, in which a hologram of the eye captured with digital camera contains in...

Optical biometry uses interferometry to measure the axial length (AL) of the eye. Traditionally, one-variable regression formulas have converted the optical path length measured by a biometer to a geometric AL. An alternate calculation of axial length sums the individual segments of the eye (sum-of-segments AL). This calculation has been shown to i...

Purpose To determine whether monocularly‐ and binocularly‐induced spherical and meridional blur and aniseikonia had similar effects on stereopsis thresholds. Methods Twelve participants with normal binocular vision viewed McGill modified random dot stereograms to determine stereoacuities in a four‐alternative forced‐choice procedure. Astigmatism w...

Purpose Myopia prevalence has increased in recent years, including the levels of high myopia. While myopia has been associated with scleral remodelling and changes in posterior scleral shape, there has been little research examining how myopia affects in-vivo anterior sclera shape. We compared anterior scleral shape in emmetropes, low to moderate m...

Purpose The sclera plays an important role in the biomechanical stability of the eye. We aimed to examine if changes in the shape of the anterior sclera occur in response to accommodation and convergence. Methods Thirty‐six healthy young adult participants aged between 18 and 30 years including 18 myopes (–0.5 to –4.0 D) and 18 emmetropes (+0.5 to...

Lighting conditions nominated for color vision testing are many and varied. The recommendation of CIE color rendering index (CIE CRI) $ {\ge} {90}$ and correlated color temperature of close to 6500 K is widely made for color vision testing generally. With the demise of incandescent and fluorescent lighting and their replacement by light-emitting di...

Purpose Stereopsis depends on horizontally disparate retinal images but otherwise concordance between eyes. Here we investigate the effect of spherical and meridional simulated anisometropia and aniseikonia on stereopsis thresholds. The aims were to determine effects of meridian, magnitude and the relative effects of the two conditions. Methods Te...

Document recommendation systems for locating relevant literature have mostly relied on methods developed a decade ago. This is largely due to the lack of a large offline gold-standard benchmark of relevant documents that cover a variety of research fields such that newly developed literature search techniques can be compared, improved and translate...

Document recommendation systems for locating relevant literature have mostly relied on methods developed a decade ago. This is largely due to the lack of a large offline gold-standard benchmark of relevant documents that cover a variety of research fields such that newly developed literature search techniques can be compared, improved and translate...

We evaluate the impact of duration on the treatment effect of multifocal spectacle lenses used to inhibit myopia progression in children. A systematic literature search identified randomized controlled trials where multifocal lenses were prescribed as the intervention, with single vision lenses as the control. Nine randomized control trials involvi...

Purpose Peripheral refraction is important in design of myopia control therapies. The aim was to investigate the influence of contact lens decentration associated with eye rotation on peripheral refraction in the horizontal visual field. Methods Participants were 10 emmetropes and 10 myopes in good general and ocular health. Right eyes underwent c...

Significance: Clinicians who administer the Farnsworth-Munsell D-15 test need to pay attention to the quality and quantity of lighting and the time that they allow for completion of the test, and all repeat attempts need to be included in reports on compliance with color vision standards. Purpose: The validity of the Farnsworth-Munsell D-15 has...

Background: One focal point of Graduate Medical Education (GME) is scholarly activity and its integration into clinical practice by evidence-based learning. Program directors and educational leaders view scholarly work as the foundation for continuing resident education; however, the high demand of scholarly activity can be cumbersome for newly ac...

Purpose: To investigate effects of Rose K2 XL semi-scleral contact lenses (Menicon Co.) on visual acuity and higher-order aberrations in eyes with irregular corneas. Methods: One hundred and twelve eyes of 84 patients fitted with Rose K2 XL lenses were analysed. Participants were in 4 clinical groups: keratoconus, intra-corneal ring segments, ra...

Significance: Vertically yoked prisms have been used in treatment of binocular vision dysfunction despite minimal supporting evidence. In people with normal binocular vision, the impact on phorias has been assessed but not the impact on accommodation, accommodation vergence interactions, or the horopter. We found that vertically yoked prisms have...

The evidence-basis based on existing myopia control trials along with the supporting academic literature were reviewed; this informed recommendations on the outcomes suggested from clinical trials aimed at slowing myopia progression to show the effectiveness of treatments and the impact on patients. These outcomes were classified as primary (refrac...

The near-vision performance of emmetropic presbyopes can be improved by the monocular surgical implantation of small-aperture corneal inlays or intraocular lenses that contain either an annular or circular stop to increase ocular depth of focus. Ray tracing is used to show that, although different stop designs and positions may produce similar axia...

Purpose: Anecdotal evidence suggests that some sunglass users prefer yellow tints for outdoor activities such as driving, and research has suggested that such tints improve the apparent contrast and brightness of real-world objects. The aim of this study was to establish whether yellow filters resulted in objective improvements in performance for v...

Significance: Nominally plano prisms can have appreciable refractive errors that exceed the usual prescribing step of 0.25 D, particularly when an eye rotates to view off-axis objects. Purpose: The purpose of this study was to determine theoretically the refractive power effects of nominally plano-refracting power prisms. Methods: Plano prisms...

Significance: Nominally plano ophthalmic prisms give autorefraction results similar to those predicted on the basis of how effective powers change with pantoscopic tilt, and magnifying lenses give autorefraction results similar to those predicted on the basis of vergence changes. Without appreciation of the optics involved, these effects might wro...