The short wavelength, i.e., blue light, is crucial for non-image forming effects such as entrainment of the circadian system in humans. Moreover, many studies showed that blue light enhances alertness and performance in cognitive tasks. However, most scientific reports in this topic are based on experiments using short exposure to blue or blue-enriched light, and only a few focused on the effects of its reduced transmittance, especially in longer periods. The latter could potentially give insight into understanding if age-related sleep problems and cognitive decline are related to less amount of blue light reaching the retina, as the eyes' lenses yellow with age. In this study, we investigated the effects of prolonged blocking of blue light on cognitive functioning, in particular-sustained attention and visuospatial working memory, as well as on sleep, and melatonin and cortisol levels. A group of young, healthy participants was randomly allocated to either blue light blocking or control group. Depending on the group, participants wore amber contact lenses, reducing the transmittance of blue light by ∼90% or regular contact lenses for a period of 4 weeks. No changes were observed for measurements related to sleep and sleep-wake rhythm. Dim light melatonin onset, evening levels of melatonin, and morning cortisol answer did not show any significant alterations during blue light (BL) blockade. The significant effects were revealed both for sustained attention and visuospatial memory, i.e., the longer blocking the blue light lasted, the greater decrease in performance observed. Additionally, the followup session conducted ∼1 week after taking off the blue-blocking lenses revealed that in case of sustained attention, this detrimental effect of blocking BL is fully reversible. Our findings provide evidence that prolonged reduction of BL exposure directly affects human cognitive functioning regardless of circadian rhythmicity.
A cataract is an opacity (clouding) of the normally clear lens which develops as a result of aging, metabolic disorders, trauma or heredity. The number of patients with cataract is increasing exponentially. This disease requires surgical intervention, to remove the cloudy lens and to introduce the eye lens polymer. In this work we will present analyses of degraded parts of human lens. Experimental materials were obtained from the lens removed during surgical intervention. These biological samples were measured using Almega XR Confocal Raman spectrometer (Thermo Scientific) with an excitation source of 785 nm laser line. The Raman vibrations in the spectral region of 650-1750 cm −1 were analyzed. The difference spectra revealed an excess of tryptophan, tyrosine, phenylalanine, β-sheet conformation, and molecules or molecular groups.
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IntroductIonA cataract is a common disease among people over 60 (except for its congenital form that occurs at birth), which is treated surgically. The direct cause of the disease is opacification of the lens leading to its damage to the eye, and statistics claim that more
PurposePhacoemulsification is one of the most popular techniques of treating cataract. During the surgery the vibrating phaco‐probe emulsifies the lens into pieces that are vacuumed into a cassette. Afterwards the shredded lens material is usually disposed. Currently spectroscopic methods are ordinarily applied for studying biological materials due to their high sensitivity, reliability and non‐destructive character. The study attempts to determine whether the infrared spectroscopy technique is appropriate to reveal the differences in the structure of the lenses, especially focusing on the content of substances indicating changes in the secondary protein structure or mineralization process.MethodsIn the study 99 randomly selected dispersed human lenses were analyzed. The procedures of phacoemulsification were performed at the Military Hospital in Cracow and Military Institute in Warsaw. Obtained shredded lenses were forwarded to the Institute of Nuclear Physics at Polish Academy of Sciences in Cracow for further investigation. After appropriate preparation, the material was analyzed by FTIR spectroscopy using Nicolet spectrometer equipped with DTGS detector and ATR attachment. For the accurate interpretation of the spectra of lenses, exemplary samples of albumin, DNA, glucose and hydroxyapatite were also analyzed.ResultsThe FTIR spectra of lenses are characteristic for natural tissues and are dominated by intense bandwidth derived from amides and lipids. The FTIR spectra of the lenses are most similar to the spectrum of albumin.ConclusionsThe material obtained during phacoemulsification is suitable for infrared spectroscopic investigation. The FTIR method allows for the determination of human eye lenses structure and enables to indicate the differences in their composition.
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