PMID: 15365385Sep 15, 2004Paper

Sources of normal and anomalous motion in retinoscopy

Optometry and Vision Science : Official Publication of the American Academy of Optometry
Donald O Mutti

Abstract

Besides the classic "with," "against," and "neutral" absence of motion, retinoscopic reflexes can display anomalous "with" motion in myopia. A model is presented that explains the source of this anomalous motion, as well as quantifies the appearance of retinoscopic motion in myopia and hyperopia. Various 2 x 2 matrices were created to describe schematic eyes for a +20 D trial lens, a Gullstrand #1 schematic eye, and an infant schematic eye. Rays from the retinoscope were traced paraxially through these matrices over a full transit of the retinoscope beam across the pupil. Retinal position of the edge of the reflex visible to the observer was plotted as a function of pupil sizes from 2 mm to 16 mm for -5.00 D and +2.00 D refractive errors for the +20 D trial lens. The edge of the retinoscopic reflex could be formed by one of two sources: the edge of the retinoscope beam itself, or the shadow cast by the beam against the edge of the pupil. Anomalous "with" motion arose in myopia when the edge of the reflex was formed by the edge of the beam. The edge of the beam was also visible in hyperopia but did not create anomalous motion. The retinoscope peephole was not involved in the formation of the edge of the reflex. The degree of ano...Continue Reading

References

Jan 1, 1989·Ophthalmic & Physiological Optics : the Journal of the British College of Ophthalmic Opticians (Optometrists)·T Raasch, V Lakshminarayanan
Jan 1, 1996·Journal of the Optical Society of America. A, Optics, Image Science, and Vision·A Roorda, W R Bobier

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Citations

May 23, 2018·Indian Journal of Ophthalmology·Jameel Rizwana HussaindeenPeter M Allen

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