Normal upper age‐limits for photopic and mesopic visual acuity and functional contrast sensitivity

Abstract

PurposeNormal, healthy aging causes a gradual worsening of vision with more pronounced effects at lower light levels (mesopic range). Normal spatial vision enables us to resolve fine spatial detail and to detect faint edges and boundaries that make up objects. Age‐related changes in the optics of the eye and diseases of the retina and / or systemic diseases that affect vision can also cause a loss of spatial vision. In order to separate the latter from the effects of normal aging, reliable, upper, normal limits of spatial vision are needed for both photopic and mesopic light levels. The purpose of this investigation was to measure visual acuity (VA) and functional contrast sensitivity (FCS) as a function of age in a large sample of normal subjects and to establish reliable, statistical limits to describe normal vision.Methods206 subjects (age range: 10‐77 years) have been investigated. A detailed medical and ocular history and eye examination were carried out. We measured photopic and mesopic VA and FCS in each subject under binocular and monocular viewing conditions with both positive and negative contrast using the Acuity‐Plus test (http://www.city.ac.uk/avot).ResultsThe best visual performance corresponds to ~ 15 to 35 years. The gradual increase in thresholds with increasing age was surprisingly small under all stimulus conditions below the fifth decade with significant differences between photopic and mesopic conditions.ConclusionsThresholds of VA and FCS increase gradually in normal aging. These preliminary results reveal a more pronounced effect between the fifth and sixth decade of life. On completion of this study, statistically‐reliable, upper, normal limits for VA and FCS will be determined as a function of age. These data will make it possible to detect reliable significant loss of spatial vision that cannot be attributed to normal aging.