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Perceived brightness with small apertures

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Session Details

Session Title: Moderated Poster Session: What is New and Hot by Great Speakers

Venue: Poster Village: Pod 1

First Author: : P.Artal SPAIN

Co Author(s): :    S. Manzanera   J. Marin           

Abstract Details


The small aperture concept is successfully used to extend depth of focus in presbyopic patients using corneal inlays or intraocular lenses with an embedded aperture. Although the use of small apertures reduces the retinal illuminance, patients often report a lesser reduction in the perceived brightness as could be expected. The purpose of this study was to quantify the relative perceived brightness when viewing through a small aperture.


Laboratorio de Optica, Universidad de Murcia


We used an instrument based in adaptive optics to determine the relative perceived brightness with a small (1.6 mm) aperture. Two apertures (3 mm and 1.6 mm diameters) were presented monocularly to the subject alternatively with an interval duration of 350 ms. With equal transmittances in both apertures, a flickering effect was perceived due to the different retinal illuminance for each condition. Subject’s task was to modify the transmittance of the 3-mm pupil until flickering was minimized. This value indicates the relative “perceived” brightness reduction. The measurements were performed under 3 average luminance levels covering photopic to mesopic ranges.


The perceived relative luminance measured ranged from 38.5% and 46.9%. This represents an increase in brightness perception with a small aperture of 1.32 and 1.61 respectively compared with what could be expected. This trend was consistent for all subjects participating in the study with small variability in the results


The perceived brightness with a small aperture is less pronounced as what could be predicted by the reduction in retinal illuminance. Under real visual conditions, this effect could be even more significant since binocular effects and temporal adaptation may further increase the perceived brightness with the small aperture.

Financial Disclosure:

receives consulting fees, retainer, or contract payments from a company producing, developing or supplying the product or procedure presented

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