![]() The instruments mentioned above share common characteristics as follows: (1) Each measurement focuses on a single Point of Interest (POI), which is controlled by fixation targets placed in multiple locations. In recent studies, the open-field refractor is commonly used by researchers, such as the SRW5000 10 /SRW5001 11 (Ajinomoto, Japan), NVision K-5001 12 (Shin-Nippon, Japan) and WAM-5500 13 (Grand-Seiko, Tokyo, Japan). Peripheral refraction measurement with Shack Hartman aberrometer were performed by David 8 in 2007 and Linda 9 in 2009. This method involved directing a narrow laser beam into the eye through a specific point on the pupil and capturing the aerial image of the retinal spot with a CCD camera. utilized a laser raytracing method 7 to investigate the monochromatic aberrations of the human eye along the temporal meridian. In 1977, Jennings and Charman 6 introduced a double-pass photo-electric ophthalmoscopic method to objectively study the variation in image quality across the retina by analyzing the reflected image of a fine line, known as the line spread-function. The examiner selected the appropriate lens based on the motion of the retinoscopic shadow until a neutral state was achieved. This involves framing positive and negative lenses on a rotatable disc, which is placed in front of each eye of the subject. In 1971, Hoogerheide and Rempt 4, 5 investigated the relationship between myopia and peripheral refraction in pilots using a retinoscope. ![]() 1, 2, 3 pioneered the measurement of peripheral refraction by modifying a Zeiss parallax refractometer and mounting it onto a rotatable carriage enabling measurements along the horizontal meridian from temporal 60° to nasal 60°. Peripheral refraction has been a subject of study for several decades, and versatile measurement tools have been employed for different purposes. The study demonstrates agreement among the test results, simulation results, and expected refraction on three test eyes. ![]() Test results are compared with simulation results and expected refraction. Both simulation results and experimental results are obtained by combining the test eyes and RT system. ![]() Three test eyes of − 15 D, 0 D, and + 15 D are defined, and expected refraction is obtained through simulation on an independent test schematic eye. The refraction characterization of RT optical system is performed using Isabel schematic eye. Refraction Characterization Function (RCF) is proposed to translate the focus position into refraction determination, thus forming the refraction topography. The maximum focus measure correlates with the optimal focus position. The refraction algorithm calculates the focus measure for multiple images at the Point of Interest and formulates them into a focus profile. Unlike conventional techniques for peripheral refraction measurement, RT requires the subject to stare at a stationary fixation target. RT develops a refraction algorithm on fundus images at various focusing statuses. The agreement of the test results obtained using RT is evaluated against simulation results and expected refraction. This paper introduces a novel focusing method Refraction Topography (RT) for wide-angle refraction measurement.
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