South American Values of the Optical Straylight Function

Abstract

Purpose: To access retinal straylight in a Brazilian sample and to compare it with European norms. Methods: Absolute Straylight was assessed using C-Quant that uses an adaptive staircase based on a 2-Alternated Forced Choice task. A young (22.2 ± 2.4 yrs, n = 20) and an old group (53.8 ± 7.4 yrs, n = 21) of subjects were tested. All refractive errors were corrected in the C-Quant device, and no subjects had ocular diseases or vision-threatening conditions (e.g., diabetes, unregulated blood pressure, high intraocular pressure, visible cataract). Eighty-five percent of all subjects in each age group had dark-pigmented eyes. Each eye was tested 3 times, yielding 6 straylight values (s). Only data fulfilling C-Quant reliability criteria were included. Results: There were no statistical differences between the three attempts on each eye (ANOVA, F = 0.993, p > 0.936) and between the two groups (ANOVA, F = 0.893, p > 0.725). Straylight values (s) were fit with an empirical equation to compare to European norms. There were no statistical differences between Brazilian straylight values and European norms for either young or old age groups (ANOVA, F = 5.114, p > 0.993). However, there was a tendency for our s values to be higher than the European norms, consistent with young Brazilian eyes having more light-scattering than age-matched European eyes. Conclusions: Consistent with European norms, light-scattering increases with age in the Brazilian sample. This increase is thought to be due, in large part, to age-related changes in lens structure and density. Although the differences between the populations are not significant, the tendency for Brazilian data to have higher s values than European values, especially at young subjects, is in the opposite direction from that expected from a dark-eyed population. This suggests the hypothesis that latitude-dependent (Sao Paulo, latitude 23° S, European latitudes between 40° N to 55° N) differences in the light environment could be associated with differences in s values.

Reduced eye optical quality contributes to worse chromatic thresholds in aging

“…As a direct consequence, visual acuity and contrast sensitivity function are reduced in aging (Alio et al, 2005;Allard et al, 2013). Recently, a negative correlation was found between the estimated straylight in the eye and the reading performance of healthy participants, suggesting that the reduction in visual performance was related to the changes in their individual optical properties (Longhi Bitencourt et al, 2019). The CIE (Commission Internationale de l'Eclairage) recently defined the ocular straylight as a visual handicap but with a more general nature, and consequently more significant, than those of the glare condition (van den Berg et al, 2013).…”

Forward‐scattered and backward‐scattered light in moderate keratoconus

“…Scattering of light at the cornea can lead to high values of straylight, which represents the light entering the eye but not reaching the retina in a focused manner, thereby forming a veil of light over the retina. The effect of glare sensitivity resulting in visual impairment is called disability glare, which is defined by the CIE ( Commission Internationale d'Eclairage ) as retinal straylight, a result of studies that showed that disability glare can be understood on the basis of light scattering in the eye 9 . This disability glare represents the loss of retinal image contrast as a result of intraocular light scatter, or straylight, and it is one of the most widely reported symptoms by patients with KC 10 …”

“…The effect of glare sensitivity resulting in visual impairment is called disability glare, which is defined by the CIE (Commission Internationale d'Eclairage) as retinal straylight, a result of studies that showed that disability glare can be understood on the basis of light scattering in the eye. 9 This disability glare represents the loss of retinal image contrast as a result of intraocular light scatter, or straylight, and it is one of the most widely reported symptoms by patients with KC. 10 For those reasons, as KC progresses, not only is the perceived vision altered but also the optical quality of the eye and the patient's quality of life are affected.…”

Erratum: Longhi Bitencourt, E. et al. South American Values of the Optical Straylight Function. Vision 2020, 4, 2

“…The authors wish to make the following erratum to this paper [1]. Request to exclude author Nestor Norio Oiwa from the authorship.…”