Skip to main content

Research Repository

See what's under the surface

Advanced Search

The effect of pupil size on static and dynamic measurements of accommodation using an infra-red optometer

Winn, B; Pugh, JR; Gilmartin, B; Owens, H

Authors

B Winn

JR Pugh

B Gilmartin



Abstract

The study examines to what degree the output of the Canon Auto-ref R1 infra-red (IR) optometer is affected by variations in pupil size for both static measurement of refractive error and for continuous recording of accommodation when switched to its modified mode of operation. In the normal static mode of operation the measurement of refractive state simply depends on the position of the peak photodetector output for each of three meridians: it does not depend on signal amplitude and hence pupil size. However, in continuous mode the actual output of a single photodiode is measured and the measurement is susceptible to changes in pupil size that occur within the area of the exit pupil utilized by the instrument. Using static and dynamic recording on model and human eyes the study shows that a 10% reduction in output signal relative to the maximum output level (for a constant stimulus) occurs for pupil sizes of 3.9 mm. The relatively small exit pupil has important advantages with regard to the use of mydriatic drugs and task-induced changes in pupil diameter.

Journal Article Type Article
Publication Date Jul 1, 1989
Journal Ophthalmic & physiological optics : the journal of the British College of Ophthalmic Opticians (Optometrists)
Print ISSN 0275-5408
Publisher Wiley
Peer Reviewed Peer Reviewed
APA6 Citation Winn, B., Pugh, J., Gilmartin, B., & Owens, H. (1989). The effect of pupil size on static and dynamic measurements of accommodation using an infra-red optometer. Ophthalmic and Physiological Optics,
Keywords Pupil, Mydriatics, Photodetector Device Component, Visual Accomodation, Meridians, Eye
;