Methodology to evaluate glare effects in corrected ammetropic subjects

ANÍBAL DE PAUL; ELISA COLOMBO; SILVIA COMASTRI; JUAN ANTONIO APARICIO; JOSÉ ANTONIO MENÉNDEZ; LUIS ISSOLIO

Óptica Pura y Aplicada

Sociedad Española de Óptica

Lugar: Madrid; Año: 2013 vol. 46 p. 285 - 293

0030-3917

Light originated at a glare source and entering the eye, produces a veiling luminance that causes contrast decrease in retinal images and this effect could differ if the subject wears lenses or not. In this work the glare effects in subjects wearing lenses is studied inducing ammetropies in emmetropes. Contrast thresholds of sinusoidal patterns of 2 cpd and 0.5 cd/m2 are evaluated without and with glare, the glare source being steady, at 12o and producing 60 lx at the cornea. To exemplify the use of this methodology, 2 emmetropes under 8 different conditions are considered: naked eye; 3 control conditions (wearing neutral lenses) and 4 ammetropic conditions, inducing low (2 D) and medium (5 D) myopia and hyperopia with positive and negative contact lenses and correcting them with adequate ophthalmic lenses. The contrast threshold differences between the naked eye and the other 7 conditions are statistically not significant without glare and significant (up to more than 100%) with glare, independently of lens power and probably due to ectopic scattering and multiple reflections. The method proposed enables the determination of the glare effects if lenses are worn though a greater population is required to attain conclusive data.