Accommodation stimulus and response determinations with autorefractors

Atchison, David A.; Varnas, Saulius R.

doi:10.1111/opo.12340

Cited by 23 publications

(27 citation statements)

References 19 publications

(31 reference statements)

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“…These measurements were captured using a COAS-HD wavefront sensor (produced by the former company, Wavefront Sciences Inc., later acquired by Lumetrics, www.lumetrics.com), which is based on the Hartmann-Shack principle and has been well-validated. 26,27 An eighth order Zernike polynomial was fit across a 2.3 mm pupil for each participant at each accommodation demand, from which the refractive power vectors, M, J 180 , and J 45 , were determined from the wavefront slope using the methods of Iskander et al 28 Atchison and Varnas 29 suggested that accommodation measurements obtained using autorefractors depend on several factors, including the method used to stimulate accommodation, and discrepancies between subjective and objective refraction measurements. Since the accommodation demands presented via the Badal optometer were based on the non-cycloplegic subjective refraction and the accommodation response (and errors) were determined using measurements from the COAS-HD, the equations presented by Atchison and Varnas 29 were used to determine the "adjusted" accommodation errors, where a negative and positive value indicates a lead and lag of accommodation, respectively.…”

Section: Methodsmentioning

confidence: 99%

Changes in ocular biometry during short‐term accommodation in children

Hughes

Read

Collins

et al. 2020

Ophthalmic Physiologic Optic

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Purpose Near work has been linked with myopia development; however, the underlying mechanism remains unclear. Small increases in axial length during accommodation have previously been reported in adults, and therefore, this study aimed to examine if accommodation‐induced changes in ocular biometry also occur in school‐aged children. Methods A range of ocular biometric measurements were captured during brief accommodation tasks at four demands (0, 3, 6, and 9 D), in a group of 87 non‐myopic, school‐aged children using a Badal optometer mounted to a non‐contact optical biometer (Zeiss IOLMaster 700, https://www.zeiss.com/meditec/int/product-portfolio/optical-biometers/iolmaster-700.html). Reliable biometry measurements and active accommodation were observed for 76 participants who were included in the analysis. The average central corneal thickness (CCT), anterior chamber depth (ACD), crystalline lens thickness (LT), anterior segment length (ASL), vitreous chamber depth (VCD), and axial length (AL) were determined for each accommodation demand. Raw measurements of AL and VCD were corrected to account for the effect of LT changes during accommodation. Results On average, AL increased with increasing levels of accommodation (p = 0.005). The mean (SEM, standard error of the mean) AL increase from 0 D to the 3, 6, and 9 D demands was 4 (1), 8 (1), and 15 (2) µm, respectively. All other biometric parameters, except CCT, changed significantly during accommodation. LT and ASL increased, and ACD and VCD decreased significantly with increasing accommodation (all p ≤ 0.02). A longer baseline AL was associated with greater levels of accommodation‐induced axial elongation at the 9 D demand (p < 0.0001). Conclusions AL increased significantly during accommodation in children, consistent with previous findings in adults up to a 6 D demand. AL continued to increase for higher levels of accommodation (9 D demand), which children may experience during near tasks. These findings provide further insights into potential mechanisms linking near work, axial elongation, and myopia development. However, no myopic children participated in this experiment; therefore, further research is required.

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Section: Methodsmentioning

confidence: 99%

Changes in ocular biometry during short‐term accommodation in children

Hughes

Read

Collins

et al. 2020

Ophthalmic Physiologic Optic

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“…It is also important to understand an important limitation of the technique: the use of the red stimulus could have caused greater accommodative stimulus and, consequently, higher accommodative responses. Due to the chromatic aberrations of the human eye, there is a higher accommodation when the subject reads with red light [ 37 ].…”

Section: Discussionmentioning

confidence: 99%

Real-Time Measurement of Ocular Wavefront Aberrations in Symptomatic Subjects

Franco

Gomes

2018

BioMed Research International

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The purpose of this work was to study the real-time changes of the optical properties of the eye with accommodation in subjects with symptoms of accommodative disorders. From ocular aberrations, it is possible to compute several parameters like the response and lag of accommodation. The ocular aberrations were measured in 4 subjects, with different accommodative disorders, during several cycles of accommodation/disaccommodation and for different accommodative stimuli. The measurement was done continuously and in real time during different accommodative stimuli. It was possible to see the changes in accommodative response during the several stimuli of accommodation. Subjects with accommodative disorders showed different accommodative responses. The use of wavefront ocular aberrations can be a tool to diagnose accommodative disorders. In some subjects with complaints, this method showed irregularities even when the results of the usual clinical exams were normal.

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“…The entire testing was conducted through the subject’s best distance refraction. This study used the formulas suggested by Atchison and Varnas (2017) to calculate the accommodative stimulus, accommodative response, and accommodative lag/lead for each participant at the three accommodative demands [ 37 ]. The calculation steps of the three formulas are

where AS represents accommodative stimulus; L , object vergence; d , vertex distance; and SR , spectacle refraction.…”

Section: Methodsmentioning

confidence: 99%

Accommodative Response in Patients with Central Field Loss: A Matched Case-Control Study

Alsaqr

AlShareef

Alhajri

et al. 2021

Vision

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Purpose: This study was conducted to evaluate the accommodative response in young participants with visual impairment in comparison with visually normal participants. Methods: Fifteen participants with confirmed visual impairment and 30 visually normal participants aged 12–15 years were recruited. Accommodative response was measured using autorefractor (Grand Seiko WV500) at distances of accommodative demand of 33, 25, and 20 cm. The targets were one-line-above participant threshold acuity. The participants’ accommodative responses were compared between both groups after calibration for refractive errors and the vertex distance of the glasses. Visual acuity and refractive status were also assessed. Results: The age was not significantly different between both participant groups. The visual acuity of visually impaired patients was 6/30 to 6/240, and that of visually normal participants was 6/7.5 or better. Ten of the visually impaired patients and 29 of visually normal participants were myopic. In total, 61–73% of visually impaired patients showed an accommodative lead. Five subtypes of accommodative response were observed. In general, the accommodative inaccuracy increased with increasing accommodative demand. However, the visually normal participants largely exhibited an accommodative lag. A mild-to-moderate relationship was observed between visual acuity and accommodative response (r = 0.3–0.5, p < 0.05). Conclusion: Accommodative response in young visually impaired patients can be variable and on an individual basis. Low vision specialists should anticipate accommodative response outside the normal range. Therefore, we shall consider evaluating each patient’s accommodative response before prescribing any near addition lenses. Accommodation inaccuracy is often more complex than predicted due to increased depth of focus caused by reduced visual acuity.

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Accommodation stimulus and response determinations with autorefractors

Abstract: Accurate equations for accommodation stimulus and accommodation response for a range of accommodation stimuli in different setups have been developed.

Cited by 23 publications

References 19 publications

Changes in ocular biometry during short‐term accommodation in children

Changes in ocular biometry during short‐term accommodation in children

Real-Time Measurement of Ocular Wavefront Aberrations in Symptomatic Subjects

Accommodative Response in Patients with Central Field Loss: A Matched Case-Control Study

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