Validation of a simple-to-use, affordable, portable, wavefront aberrometry-based auto refractometer in the adult population: A prospective study

Rao, Divya Parthasarathy; Negiloni, Kalpa; Gurunathan, Sivasundaravadivel; Velkumar, Selvaraj; Sivaraman, Anand; Baig, Adeeb Ulla; Kumari, B; Murali, Kaushik

doi:10.1186/s12886-022-02684-5

Cited by 3 publications

(7 citation statements)

References 14 publications

(21 reference statements)

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“…The variability in subjective refraction for M observed here was slightly lower than that found in previous studies quantifying this parameter, 12,14 in which 40–50 subjective refractions were used for the estimation. The LOA reported in earlier investigations (±1.0 D) was comparable with the value noted here between QSFree and subjective refraction and in other recent works validating portable autorefractors 7,11,15,20 . In contrast, the LOAs and mean bias error for the astigmatic components ( J 0 , J 45 ) were comparable between the three methods.…”

Section: Discussionsupporting

confidence: 90%

“…The LOA reported in earlier investigations (±1.0 D) was comparable with the value noted here between QSFree and subjective refraction and in other recent works validating portable autorefractors. 7,11,15,20 In contrast, the LOAs and mean bias error for the astigmatic components (J 0 , J 45 ) were comparable between the three methods. Compared to other portable autorefractors, LOAs between QSFree and SR1 (±0.44 D [J 0 ], ±0.36 D [J 45 ]) and between QSFree and SR2 (±0.38 D [J 0 ], ±0.33 D [J 45 ]) were significantly better than those reported by Rao et al 20 (±0.80 D [J 0 ] and ±1.00 D [J 45 ]), or Ciuffreda and Rosenfield 6 (±0.86 D [J 0 ] and ±0.37 D [J 45 ]), using two different commercially available portable wavefront autorefractors.…”

Section: Comparisonmentioning

confidence: 82%

“…To validate this novel device, a new study design was proposed to account for the variability in the subjective refraction process. Specifically, in contrast to previous clinical investigations that have validated portable autorefraction technologies by evaluating the difference between the device and subjective refraction by a single ECP, 7,9,20 this study compared the differences between the autorefractor and subjective refractions performed by two independent ECPs with the differences between the subjective refraction measurements (as performed by the two ECPs). This provided a measure of the device's accuracy against the inherent variability of the subjective refraction procedure.…”

Section: Introductionmentioning

confidence: 99%

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Ametropia detection using a novel, compact wavefront autorefractor

Hernández,

Gil,

Zaytouny

et al. 2023

Ophthalmic Physiologic Optic

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IntroductionDespite the well‐known reproducibility issues of subjective refraction, most studies evaluating autorefractors compared differences between the device and subjective refraction. This work evaluated the performance of a novel handheld Hartmann–Shack‐based autorefractor using an alternative protocol, which considered the inherent variability of subjective refraction.MethodsParticipants underwent an initial measurement with a desktop autorefractor, two subjective refractions (SR1 and SR2) and a final measurement with the QuickSee Free (QSFree) portable autorefractor. Autorefractor performance was evaluated by comparing the differences between the QSFree and each of the subjective refractions with the difference between the subjective refractions (SR1 vs. SR2) using Bland–Altman analysis and percentage of agreement.ResultsA total of 75 subjects (53 ± 14 years) were enrolled in the study. The average difference in the absolute spherical equivalent (M) between the QSFree and the SR1 and SR2 was ±0.24 and ±0.02 D, respectively, that is, very similar or smaller than the SR1 versus SR2 difference (±0.26 D). Average differences in astigmatic components were found to be negligible. The results demonstrate that differences between QSFree and both subjective refractions in J0 and J45 were within ±0.50 D for at least 96% of the measurements. The limits of agreement (LOAs) of the differences between QSFree and SR1, as well as QSFree and SR2, were higher than those observed between SR1 and SR2 for M, J0 and J45.ConclusionsA protocol was designed and validated for the evaluation of a refractive device to account for the variability of subjective refraction. This protocol was used to evaluate a novel portable autorefractor and observed a smaller difference between the device and subjective refractions than the difference between the two subjective refraction measurements in terms of mean bias error, although the standard deviation was higher.

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Section: Discussionsupporting

confidence: 90%

Section: Comparisonmentioning

confidence: 82%

Section: Introductionmentioning

confidence: 99%

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Ametropia detection using a novel, compact wavefront autorefractor

Hernández,

Gil,

Zaytouny

et al. 2023

Ophthalmic Physiologic Optic

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“…As for autorefractors, when a near target is viewed within NETRA without the use of a cycloplegic, the proximity of the perceived target stimulates proximal accommodation which can lead to overaccommodation and more negative or myopic readings. Other factors include internal and external illumination levels, astigmatic aberrations, optical decentration, the contrast and type of targets and direction of focus and extraneous variables such as age and user experience and possibly fatigue that may also influence instrument myopia 40–48…”

Section: Discussionmentioning

confidence: 99%

“…It is not, however, a substitute for subjective refraction by skilled clinicians and cycloplegia is recommended where NETRA is used with younger patients. Spectacle prescriptions should not be provided directly from NETRA as there are limitations in repeatability, not so much on average, but for individual eyes in some instances 8 26 27 46. Nonetheless, NETRA could provide a starting point for subjective refraction and subsequent spectacle or contact lens prescriptions, should methods such as retinoscopy not be available.…”

Section: Discussionmentioning

confidence: 99%

Multivariate analysis of repeatability for the Near Eye Tool for Refractive Assessment (NETRA)

Hasrod,

Rubin

2023

BMJ Open Ophth

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ObjectiveTo investigate repeatability of refractive state using a smartphone-based assessment tool, the Near Eye Tool for Refractive Assessment (NETRA).Methods and analysisThis study included 279 participants, predominantly female (66.7%) of African descent (49.1%). The age range was 9–63 years with mean age (s) 22.6 (8.9) years. Two consecutive measurements per eye with the NETRA were measured for both eyes of all participants. However, analyses for the right eyes only are included here. Multivariate statistical analysis included stereo-pair comets and scatterplots with 95% surfaces of constant probability density. Correlation coefficients for repeated samples were determined. Repeatability and agreement for NETRA were assessed with Bland-Altman plots, coefficients of repeatability (CR=1.96sd;sdis the SD of differences) and intraclass correlation coefficients (ICCs).ResultsBland-Altman plots, within-subject SD (sw), coefficients of repeatability and ICC indicated that repeated measurements were similar for many but not all eyes and there was good agreement (ICC=0.96) for the spherical coefficient (FI=M) but less so for antistigmatic coefficients (FJ=J0andFK=J45) of power. Although mean differences for repeated samples were almost zero, 95% limits of agreement widths were larger for the stigmatic coefficients. Without cycloplegia, repeatability (2.77sw) was 1.63 D, 0.58 D and 0.56 D for the stigmatic and antistigmatic coefficients, respectively.ConclusionNETRA is a potentially useful and inexpensive portable method in clinical and primary health settings, and especially in less-developed regions of the world. The subjective nature of the self-refraction task can be challenging for younger individuals, and cycloplegia is recommended for NETRA with such patients.

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