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A clinical evaluation of the Shin-Nippon SRW-5000 (Japan), a newly released commercial autorefractor, was undertaken to assess its repeatability and validity compared to subjective refraction. Measurements of refractive error were performed on 200 eyes of 100 subjects (aged 24.4 ± 8.0 years) subjectively (non-cycloplegic) by one optometrist and objectively with the SRW-5000 autorefractor by a second. Repeatability was assessed by examining the differences between the seven autorefractor readings taken from each eye and by re-measuring the objective prescription of 50 eyes at a subsequent session. Although the SRW-5000 read slightly more plus than subjective refraction (mean spherical equivalent +0.16 ± 0.44 D), it was found to be highly valid (accurate) compared to subjective refraction and repeatable over the prescription range of +6.50 to -15.00 D examined. The Shin-Nippon SRW-5000 autorefractor is therefore a valuable complement to subjective refraction and as it offers the advantage of a binocular open field-of-view, has a great potential benefit for accommodation research studies. [ABSTRACT FROM AUTHOR]

A newly released commercial autorefractor, the Shin-Nippon SRW-5000 (Japan), has been found to be valid compared to subjective refraction and repeatable over a wide prescription range. Its binocular open field-of-view allows the accommodative state to be monitored while a natural environment is viewed. In conventional static mode, the device can take up to 45 readings in 1 min using digital image analysis of the reflected retinal image of a measurement ring. Continuous on-line analysis of the ring provides high (up to 60 Hz) temporal resolution of the refractive state to an accuracy of <0.001 D. Pupil size can also be analysed to a resolution of <0.001 mm. The measurement of accommodation and pupil size was relatively unaffected by eccentricity of viewing up to ±10° and instrument focusing inaccuracies of ±5 mm. The resolution properties of the analysis are shown to be ideal for measurement of dynamic accommodation and pupil responses. [ABSTRACT FROM AUTHOR]

The Canon Autoref R-1 is an ‘open-field’ autorefractor which has been widely used for research purposes for the past 20 years, but is no longer manufactured. A new autorefractor, the Shin-Nippon SRW-5000, is now available, and if measures using this instrument are shown to be equally accurate and reliable, is likely to replace the R-1. Here we report on the accuracy and reliability (repeatability and reproducibility) of refraction measures in a paediatric population (from 4 to 8 years of age). Subject numbers were 44 for cycloplegic measures and 53 for non-cycloplegic measures. As would be expected, agreement with cycloplegic refraction and reliability were better when SRW-5000 measures were taken using cycloplegia. Repeatability results from the SRW-5000 autorefractor, both with and without cycloplegia were similar to those reported for the Canon R-1. [ABSTRACT FROM AUTHOR]