Optical density of the aging human ocular media in the visible and the UV

Abstract

We analyzed the literature on the absorption in the young and aging human eye media. Five templates were derived to provide an adequate description of the spectra from 300 to 700 nm for the lens, cornea, aqueous, and vitreous. Two templates were found in all media. They stand for Rayleigh scatter and the absorbance of tryptophan. Three additional templates for the lens represent absorbance in kynurenine derivatives, such as 3-hydroxykynurenine glucoside (3HKG), and absorbance in two substances found at older age. Except for Rayleigh scatter, all templates have a Gaussian shape. Aging-trend functions were derived that show a linear slope on an age-squared scale. The result can be used to correct for media losses in visual perception tasks, in fundus reflectometry, and in studies on light damage.

Light damage to the retina: an historical approach

“…9 At the shortwavelength side the cutoff wavelength shifts to longer wavelengths with increasing age, thereby offering increased protection. The thermal action spectrum set by absorption of light by melanin is nearly flat in the visible range.…”

Evaluation of discomfort glare in the 50+ elderly: experimental study

“…The key aspect is adaptation on all levels: individual, organizational and societal and it is associated, among other things, with the adjustment of the working environment (including lighting) to the psycho-physiological capacities of the elderly. The studies dedicated to the lighting for older people concerned mainly many aspects of local lighting [20][21][22], and aspects of increasing the level of illuminance [20,23,24] or the color of light [25]. Taking into account that some studies pointed out that elderly people are more sensitive to disability glare [24][25][26], it would be worth taking into consideration discomfort glare and determining the possible changes in lighting recommendations for the UGR value.…”

“…One glare rating unit is the least detectable step and 3 units make an acceptable step in glare criteria [19]. The theoretical range of the UGR scale is from 10 to 30 [19], but the practical range used in the European standard EN 12464-1 [17] is from 16 to 28 (16,19,22,25,28). High values of UGR correspond to significant discomfort glare, while a low value indicates little discomfort glare.…”

Macular Pigment and Lens Optical Density Measurements-Evaluating a Flicker Machine with Novel Features

“…35 As a result of the spatial distribution profile of the MP, the elimination or minimization of flicker for the entire stimulus is affected by the presence of MP along with other pre-receptoral filters, chiefly the lens in the eye. 46,47 For the foveal measurements, the subject is directed to keep his/her gaze fixed at the center of the presented stimulus and to adjust a handheld control to achieve a flicker null. For subjects who find difficult the simultaneous operation of the control and keeping their gaze fixated, there is the provision in some instruments for the operator to adjust the settings.…”

“…Cataract is one of the leading causes of vision impairment in the world especially amongst the elderly. The overall optical density of the lens changes with age 47 ,with the nuclear 121 and the cortical 121 regions being the primary areas showing age-related opacity changes. However,opacity developed in the posterior subcapsular region is not age-related 79 but due to reasons such as steroid intake 122 , diabetes 123 and exposure to ionizing radiation 124 .…”