Clinical evaluation of the Shin-Nippon SRW-5000 autorefractor in adults

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±0.44D), it was found to be highly valid (accurate) compared to subjective refraction and repeatable over the prescription range of +6.50 to -15.00D 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. Copyright © 2001 The College of Optometrists.

Dynamic measurement of accommodation and pupil size using the portable Grand Seiko FR-5000 autorefractor

PURPOSE. The purpose of this study was to evaluate the potential of the portable Grand Seiko FR-5000 autorefractor to allow objective, continuous, open-field measurement of accommodation and pupil size for the investigation of the visual response to real-world environments and changes in the optical components of the eye. METHODS. The FR-5000 projects a pair of infrared horizontal and vertical lines on either side of fixation, analyzing the separation of the bars in the reflected image. The measurement bars were turned on permanently and the video output of the FR-5000 fed into a PC for real-time analysis. The calibration between infrared bar separation and the refractive error was assessed over a range of 10.0 D with a model eye. Tolerance to longitudinal instrument head shift was investigated over a ±15 mm range and to eye alignment away from the visual axis over eccentricities up to 25.0°. The minimum pupil size for measurement was determined with a model eye. RESULTS. The separation of the measurement bars changed linearly (r = 0.99), allowing continuous online analysis of the refractive state at 60 Hz temporal and approximately 0.01 D system resolution with pupils >2 mm. The pupil edge could be analyzed on the diagonal axes at the same rate with a system resolution of approximately 0.05 mm. The measurement of accommodation and pupil size were affected by eccentricity of viewing and instrument focusing inaccuracies. CONCLUSIONS. The small size of the instrument together with its resolution and temporal properties and ability to measure through a 2 mm pupil make it useful for the measurement of dynamic accommodation and pupil responses in confined environments, although good eye alignment is important. Copyright © 2006 American Academy of Optometry.

Objective accommodative amplitude and dynamics with the 1CU accommodative intraocular lens

PURPOSE. To compare the objective accommodative amplitude and dynamics of eyes implanted with the one-compartment-unit (1CU; HumanOptics AG, Erlangen, Germany) accommodative intraocular lenses (IOLs) with that measured subjectively. METHODS. Twenty eyes with a 1CU accommodative IOL implanted were refracted and distance and near acuity measured with a logMAR (logarithm of the minimum angle of resolution) chart. The objective accommodative stimulus-response curve for static targets between 0.17 and 4.00 D accommodative demand was measured with the SRW-5000 (Shin-Nippon Commerce Inc., Tokyo, Japan) and PowerRefractor (PlusOptiX, Nürnberg, Germany) autorefractors. Continuous objective recording of dynamic accommodation was measured with the SRW-5000, with the subject viewing a target moving from 0 to 2.50 D at 0.3 Hz through a Badal lens system. Wavefront aberrometry measures (Zywave; Bausch & Lomb, Rochester, NY) were made through undilated pupils. Subjective amplitude of accommodation was measured with the RAF (Royal Air Force accommodation and vergence measurement) rule. RESULTS. Four months after implantation best-corrected acuity was -0.01 ± 0.16 logMAR at distance and 0.60 ± 0.09 logMAR at near. Objectively, the static amplitude of accommodation was 0.72 ± 0.38 D. The average dynamic amplitude of accommodation was 0.71 ± 0.47 D, with a lag behind the target of 0.50 ± 0.48 seconds. Aberrometry showed a decrease in power of the lens-eye combination from the center to the periphery in all subjects (on average, -0.38 ± 0.28 D/mm). Subjective amplitude of accommodation was 2.24 ± 0.42 D. Two years after 1CU implantation, refractive error and distance visual acuity remained relatively stable, but near visual acuity, and the subjective and objective amplitudes of accommodation decreased. CONCLUSIONS. The objective accommodating effects of the 1CU lens appear to be limited, although patients are able to track a moving target. Subjective and objective accommodation was reduced at the 2-year follow-up. The greater subjective amplitude of accommodation is likely to result from the eye's depth of focus of and the aspheric nature of the IOL. Copyright © Association for Research in Vision and Ophthalmology.

Simultaneous continuous recording of accommodation and pupil size using the modified Shin-Nippon SRW-5000 autorefractor

The internal optics of the recent models of the Shin-Nippon SRW-5000 autorefractor (also marketed as the Grand Seiko WV-500) have been modified by the manufacturer so that the infrared measurement ring has been replaced by pairs of horizontal and vertical infrared bars, on either side of fixation. The binocular, open field-of-view, allowing the accommodative state to be objectively monitored while a natural environment is viewed, has made the SRW-5000 a valuable tool in further understanding the nature of the oculomotor response. It is shown that the root-mean-square of model eye measures was least (0.017 ± 0.002D) when the separation of the horizontal measurement bars were averaged twice. The separation of the horizontal bars changes by 3.59 pixels/dioptre (r2 = 0.99), allowing continuous on-line analysis of the refractive state at up to 60 Hz temporal resolution to an accuracy of <0.001D, with pupils >3 mm. The pupil edge is not obscured in the diagonal axis by the measurement bars, unlike the ring of the original optics, so in the newer model pupil size can be measured simultaneously at the same rate with a resolution of <0.001 mm. The measurements of accommodation and pupil size are relatively unaffected by eccentricity of viewing up to ±10° from the visual axis and instrument focusing inaccuracies over a range of 10 mm towards the eye and 5 mm away from the eye. The resolution and temporal properties of the analysis are therefore ideal for the simultaneous measurement of dynamic accommodation and pupil responses. © 2004 The College of Optometrists.

Continuous recording of accommodation and pupil size using the Shin-Nippon SRW-5000 autorefractor

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 1min using digital image analysis of the reflected retinal image of a measurement ring. Continuous on-line analysis of the ring provides high (up to 60Hz) temporal resolution of the refractive state to an accuracy of <0.001D. Pupil size can also be analysed to a resolution of <0.001mm. The measurement of accommodation and pupil size was relatively unaffected by eccentricity of viewing up to ±10° and instrument focusing inaccuracies of ±5mm. The resolution properties of the analysis are shown to be ideal for measurement of dynamic accommodation and pupil responses. Copyright © 2001 The College of Optometrists.

Clinical evaluation of the Shin-Nippon SRW-5000 autorefractor in adults:an update

Purpose: The Shin-Nippon SRW-5000 is an open view autorefractor that superseded the Canon R-1 autorefractor in the mid-1990s and has been used widely in optometry and vision science laboratories. It has been used to measure refractive error, accommodation responses both statically and dynamically, off-axis refractive error, and adapted to measure pupil size. This paper presents an overview of the original 2001 clinical evaluation of the SRW-5000 in adults (Mallen et al., Ophthal Physiol Opt 2001; 21: 101) and provides an update on the use and modification of the instrument since the original publication. Recent findings: The SRW-5000 instrument, and the family of devices which followed, have shown excellent validity, repeatability, and utility in clinical and research settings. The instruments have also shown great potential for increased research functionality following a number of modifications. Summary: The SRW-5000 and its derivatives have been, and continue to be, of significant importance in our drive to understand myopia progression, myopia control techniques, and oculomotor function in human vision.

Variables affecting the precision and accuracy of the Intoxilyzer 5000

The Intoxilyzer 5000 was tested for calibration curve linearity for ethanol vapor concentration between 0.020 and 0.400g/210L with excellent linearity. Calibration error using reference solutions outside of the allowed concentration range, response to the same ethanol reference solution at different temperatures between 34 and 38$\sp\circ$C, and its response to eleven chemicals, 10 mixtures of two at the time, and one mixture of four chemicals potentially found in human breath have been evaluated. Potential interferents were chosen on the basis of their infrared signatures and the concentration range of solutions corresponding to the non-lethal blood concentration range of various volatile organic compounds reported in the literature. The result of this study indicates that the instrument calibrates with solutions outside the allowed range up to $\pm$10% of target value. Headspace FID dual column GC analysis was used to confirm the concentrations of the solutions. Increasing the temperature of the reference solution from 34 to 38$\sp\circ$C resulted in linear increases in instrument recorded ethanol readings with an average increase of 6.25%/$\sp\circ$C. Of the eleven chemicals studied during this experiment, six, isopropanol, toluene, methyl ethyl ketone, trichloroethylene, acetaldehyde, and methanol could reasonably interfere with the test at non-lethal reported blood concentration ranges, the mixtures of those six chemicals showed linear additive results with a combined effect of as much as a 0.080g/210L reading (Florida's legal limit) without any ethanol present. ^