Search tips
Search criteria

Results 1-3 (3)

Clipboard (0)
more »
Year of Publication
Document Types
1.  Intrinsically photosensitive retinal ganglion cell function in relation to age: A pupillometric study in humans with special reference to the age-related optic properties of the lens 
BMC Ophthalmology  2012;12:4.
The activity of melanopsin containing intrinsically photosensitive ganglion retinal cells (ipRGC) can be assessed by a means of pupil responses to bright blue (appr.480 nm) light. Due to age related factors in the eye, particularly, structural changes of the lens, less light reaches retina. The aim of this study was to examine how age and in vivo measured lens transmission of blue light might affect pupil light responses, in particular, mediated by the ipRGC.
Consensual pupil responses were explored in 44 healthy subjects aged between 26 and 68 years. A pupil response was recorded to a continuous 20 s light stimulus of 660 nm (red) or 470 nm (blue) both at 300 cd/m2 intensity (14.9 and 14.8 log photons/cm2/s, respectively). Additional recordings were performed using four 470 nm stimulus intensities of 3, 30, 100 and 300 cd/m2. The baseline pupil size was measured in darkness and results were adjusted for the baseline pupil and gender. The main outcome parameters were maximal and sustained pupil contraction amplitudes and the postillumination response assessed as area under the curve (AUC) over two time-windows: early (0–10 s after light termination) and late (10–30 s after light termination). Lens transmission was measured with an ocular fluorometer.
The sustained pupil contraction and the early poststimulus AUC correlated positively with age (p = 0.02, p = 0.0014, respectively) for the blue light stimulus condition only.
The maximal pupil contraction amplitude did not correlate to age either for bright blue or red light stimulus conditions.
Lens transmission decreased linearly with age (p < 0.0001). The pupil response was stable or increased with decreasing transmission, though only significantly for the early poststimulus AUC to 300 cd/m2 light (p = 0.02).
Age did not reduce, but rather enhance pupil responses mediated by ipRGC. The age related decrease of blue light transmission led to similar results, however, the effect of age was greater on these pupil responses than that of the lens transmission. Thus there must be other age related factors such as lens scatter and/or adaptive processes influencing the ipRGC mediated pupil response enhancement observed with advancing age.
PMCID: PMC3411473  PMID: 22471313
2.  Optical effects of exposing intact human lenses to ultraviolet radiation and visible light 
BMC Ophthalmology  2011;11:41.
The human lens is continuously exposed to high levels of light. Ultraviolet radiation is believed to play a causative role in the development of cataract. In vivo, however, the lens is mainly exposed to visible light and the ageing lens absorbs a great part of the short wavelength region of incoming visible light. The aim of the present study was to examine the optical effects on human lenses of short wavelength visible light and ultraviolet radiation.
Naturally aged human donor lenses were irradiated with UVA (355 nm), violet (400 and 405 nm) and green (532 nm) lasers. The effect of irradiation was evaluated qualitatively by photography and quantitatively by measuring the direct transmission before and after irradiation. Furthermore, the effect of pulsed and continuous laser systems was compared as was the effect of short, intermediate and prolonged exposures.
Irradiation with high intensity lasers caused scattering lesions in the human lenses. These effects were more likely to be seen when using pulsed lasers because of the high pulse intensity. Prolonged irradiation with UVA led to photodarkening whereas no detrimental effects were observed after irradiation with visible light.
Irradiation with visible light does not seem to be harmful to the human lens except if the lens is exposed to laser irradiances that are high enough to warrant thermal protein denaturation that is more readily seen using pulsed laser systems.
PMCID: PMC3265411  PMID: 22208285
3.  Early lens aging is accelerated in subjects with a high risk of ischemic heart disease: an epidemiologic study 
BMC Ophthalmology  2006;6:16.
Ischemic heart disease (IHD) is one of the most important causes of mortality and morbidity in the Western world. There is a relationship between aging of the lens of the human eye and cardiovascular disease. The present study was conducted to examine if the risk of ischemic heart disease could be estimated by fluorophotometric assessment of lens aging.
A total of 421 subjects were included. Risk of IHD was estimated from non-ocular data using the Precard ® software. Lens aging was quantified by lens fluorometry.
The risk of IHD was strongly related to lens fluorophore accumulation (p = 0.001). The relationship between IHD and lens aging was attributable to tobacco smoking and dysglycemia.
The risk of ischemic heart disease related to smoking and diabetes mellitus can be estimated using the aging of the lens of the eye as a biomarker for generalized tissue-damage.
PMCID: PMC1459876  PMID: 16618373

Results 1-3 (3)