Modification of the Canon Auto Ref R1 for use as a continuously recording infra‐red optometer

Pugh, John R.; Winn, Barry

doi:10.1111/j.1475-1313.1988.tb01186.x

Cited by 39 publications

(24 citation statements)

References 11 publications

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“…30 Pupil size was monitored at the same time on a calibrated scale on the alignment monitor, which provides an enlarged view (8.2ϫ) of the pupil and iris. This ensured that the subject's pupil size was within the limit for which the instrument allows accurate recordings.…”

Section: Methodsmentioning

confidence: 99%

Retinotopic Accommodation Responses in Myopia

Seidel¹,

Gray²,

Heron³

2003

Invest. Ophthalmol. Vis. Sci.

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The experiments demonstrate a reduction in retinotopic processing in LOMs, which results in an increased variability in their dynamic accommodation response to stationary near targets and reduced performance for dynamic step tasks. The results demonstrate a reduced blur appreciation under dynamic conditions in these refractive groups that may lead to periods of retinal image blur of varying magnitude during near work.

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Section: Methodsmentioning

confidence: 99%

Retinotopic Accommodation Responses in Myopia

Seidel¹,

Gray²,

Heron³

2003

Invest. Ophthalmol. Vis. Sci.

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“…The value was not calculated from the magnitude of the signals and therefore was unaffected by the pupil size above a threshold diameter (2.9 mm). It measured refractive status in about 200 ms (Pugh and Winn, 1988) and would take a repeat measure in a minimum of about 1 s. Changes in apparent accommodation were <0.25 D with gaze within 3° of the optical axis of the instrument (McBrien and Millodot, 1987).…”

Section: Introductionmentioning

confidence: 99%

“…In continuous mode, the lens carriage was disabled and set manually to the linear portion of the voltage output/time curve. The voltage output from one of the three detectors was sampled continuously to indicate the amount of defocus present (Pugh and Winn, 1988; Davis et al , 1993). The focusing lens was now stationary, so changes in accommodation affecting the focus of IR radiation on the photocell varied the intensity‐related output voltage.…”

Section: Introductionmentioning

confidence: 99%

Continuous measurement of accommodation in human factor applications

Wolffsohn

Hunt

Gilmartin

2002

Ophthalmic Physiologic Optic

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It has long been sought to measure ocular accommodation continuously in human factor applications such as driving or flying. Open-field autorefractors such as the Canon R-1 could be converted to allow continuous, objective recording, but steady eye fixation and head immobilisation were essential for the measurements to be valid. Image analysis techniques utilised by newer open-view autorefractors such as the Shin-Nippon SRW-5000 are more tolerant to head and eye movements, but perhaps the technique with the greatest potential for the measurement of accommodation in human factor applications is photoretinoscopy. This paper examines the development of techniques for high temporal measurements of accommodation and reports on the tolerance of one such recent commercial instrument, the PowerRefractor (PlusOptiX). The instrument was found to be tolerant to eye movements from the optical axis of the instrument (approximately 0.50 DS change in apparent accommodation with gaze 25 degrees eccentric to the optical axis), longitudinal head movement (<0.25 DS from 8 cm towards and 20 cm away from the correct photorefractor to eye distance) and changes in background illuminance (<0.25 DS from 0.5 to 20 cd m(-2) target luminance). The PowerRefractor also quantifies the direction of gaze and pupil size, but is unable to take measurements with small pupils <3.7 +/- 1.0 mm.

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“…Objective accommodation measurements can be performed using Hartinger coincidence refractometry, 10 wavefront aberrometry, 27 dynamic retinoscopy, or open-field-of-view autorefractors. [35][36][37] Open-field refractometers that apply infrared lights are capable of measuring real binocular physiological accommodation and pupil size changes in real circumstances. During accommodation measurement, if 1 of the eyes is occluded, inaccurate data can be obtained.…”

Section: Discussionmentioning

confidence: 99%

Accommodation in phakic and pseudophakic eyes measured with subjective and objective methods

Németh

Lipécz

Szalai

et al. 2013

Journal of Cataract and Refractive Surgery

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PURPOSE:To measure accommodation subjectively and objectively and assess anterior segment changes during accommodation in phakic eyes and pseudophakic eyes. METHODS: Subjective and objective accommodation measurements and pupillometry were performed in phakic and pseudophakic patients. Refraction and pupil diameter were recorded with different accommodation stimuli. Corneal higher-order aberrations (HOAs) and anterior chamber depths (ACDs) were detected with a rotating Scheimpflug camera. RESULTS:The mean age of the 44 patients in the phakic group was 36.34 years G 16.6 (SD) and of the 27 patients in the pseudophakic group, 69.3 G 9.98 years. The mean subjective accommodation was 4.49 G 3.48 diopters (D) in phakic eyes and showed significant correlation with age, spherical aberration, changes in pupil diameter, and ACD. The mean subjective accommodation was 0.50 G 0.28 D in pseudophakic eyes. In phakic eyes, the mean objective accommodation was 0.46 G 1.02 D, 1.06 G 1.33 D, and 2.2 G 1.9 D with 2.0 D, 3.0 D, and 5.0 D, respectively, of stimulus. In pseudophakic eyes, measurable objective accommodation was recorded. In phakic eyes, the correlations were significant between these values and age, changes in ACD, pupil size, and corneal spherical aberration. In pseudophakic eyes, the only correlation was with the spherical equivalent value.

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Modification of the Canon Auto Ref R1 for use as a continuously recording infra‐red optometer

Cited by 39 publications

References 11 publications

Retinotopic Accommodation Responses in Myopia

Retinotopic Accommodation Responses in Myopia

Continuous measurement of accommodation in human factor applications

Accommodation in phakic and pseudophakic eyes measured with subjective and objective methods

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