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Proceedings Paper

Head-mounted unit for the measurement of visual performances
Author(s): Pier Giorgio Gobbi; Stefano Bozza; Francesco Carones; Rosario Brancato
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Paper Abstract

Human visual performances (visual acuity, contrast sensitivity) are commonly measured under heterogeneous ambient luminance conditions, generally referred to as 'mesopic,' without any control of the subject's pupil size. Actually, the optical performances of the eye are strongly dependent on the pupil aperture, due to the increasing effect of optical aberrations, mainly spherical aberration, which progressively degrade vision. We have developed and tested an apparatus intended to measure visual acuity and contrast sensitivity of emmetropic or ametropic subjects while continuously measuring the pupil size, which is allowed to be varied by changing the background luminance. The apparatus is mounted onto a helmet for indirect ophthalmoscopy and is driven by a personal computer, which generates characters and gratings of variable size and orientation. An infrared pupillometer keeps trace of the pupil dimension every second. The apparatus is fully described and the preliminary tests on emmetropic and ametropic subjects are reported. The measurement system is particularly suited for assessing visual performances in professional categories where keen vision is to be associated with scotopic conditions (e.g. car drivers, aircraft pilots) and as pre/post examination for all types of refractive surgery.

Paper Details

Date Published: 7 June 2000
PDF: 5 pages
Proc. SPIE 3908, Ophthalmic Technologies X, (7 June 2000); doi: 10.1117/12.387529
Show Author Affiliations
Pier Giorgio Gobbi, Hospital San Rafaele/Univ. of Milan (Italy)
Stefano Bozza, Hospital San Rafaele/Univ. of Milan (Italy)
Francesco Carones, Hospital San Rafaele/Univ. of Milan (Italy)
Rosario Brancato, Hospital San Rafaele/Univ. of Milan (Italy)


Published in SPIE Proceedings Vol. 3908:
Ophthalmic Technologies X
Pascal O. Rol; Karen Margaret Joos; Fabrice Manns, Editor(s)

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