Evaluating the cytotoxicity of contact lens multi-purpose solutions in an in vitro lens system

Purpose: To investigate the relative cytotoxic effects of contact lens multipurpose solutions on cultured crystalline lenses. Methods: A comparison of the fluorescence emission levels of cultured bovine lenses as affected by three hour experimental exposure to three contact lens multipurpose solutions (COMPLETE Moisture Plus, AMO; OPTI-FREE Express, Alcon; and ReNu MultiPlus, Bausch & Lomb) was carried out. The pre- and post-exposure fluorescence levels of the lenses were obtained and values were compared to baseline and control measurements. Results: The solutions yielded varying degrees of cytotoxicity, demonstrating significant (p < 0.01) reversible reduction of cellular viability levels of the cultured crystalline lenses as revealed by the degree of fluorescence emissions in the following order (OPTI-FREE Express > ReNu MultiPlus > COMPLETE MoisturePlus multi-purpose solutions) Conclusions: The results show that OPTI-FREE Express and ReNu MultiPlus solutions exhibited more cytotoxic effect compared to COMPLETE MoisturePlus solution. The findings support reports from previous clinical and laboratory studies. These results suggest that the in vitro approach herein presented would be a valuable system for relatively inexpensive and repeatable laboratory investigations of the possible ocular surface reactions of ophthal- mic solutions, cosmetics and pharmaceuticals at pre- and during commercial phases

Chromagen lenses and abnormal colour perception

Background: The Chromagen lens system comprises of tinted spectacle or contact lenses, each with a specific colour wavelength filter which controls the spectra of the light entering the eye. This study investigated whether spectacle-mounted Chromagen lenses would enhance colour perception in individuals with abnormal colour vision. Methods: The Ishihara colour test was used to test for colour vision deficiency (CVD) and also to evaluate the effect of the Chromagen spectacle lens on colour perception in 13 subjects. An Oculus Anomaloscope was used to confirm and sub-classify the types of CVD. Subjects comprised of school age children from the Riyadh area in Saudi Arabia. Results: The distribution amongst the male participants comprised two subjects with protanomaly, two with protanopia, five with deuteranomaly, and two with deuteranopia. Amongst the two female participants, one subject showed deuteranomaly, and one showed protanomaly. Different types of Chromagen spectacle lenses displayed some levels of colour vision enhancement depending on type of CVD. Conclusion: The findings support the notion that chromagen lenses could enhance colour vision perception in some cases of red-green colour vision defects. Clients with CVD should be managed on an individual case basis. (S Afr Optom 2011 70(2) 69-74

Eye protection practices and symptoms among welders in the Limpopo Province of South Africa+

Welding is associated with several ocular and systemic hazards especially where adequate protective measures are not taken.  The purpose of this project was to study the eye protection practices and symptoms among welders in the Capricorn District of Limpopo Province, South Africa. Questionnaires designed to investigate eye protection practices and symptoms experienced were completed byone hundred and fifty (150) welders. The types of welding done were shielded metal arc (84%), oxyacetylene gas (4%) and silver brazing (12%). The number of years spent in the welding industry ranged from one to 10 years with a mean of 5 ± 3.1 years and the number of hours of welding per day ranged from one to 10 hours with a mean of 6 ± 2.1 hours. A large percentage of the welders (89%) reported wearing protective devices when welding and the most common protective devices used by the welders were: helmets (57%), goggles(22%), and face shields (15%). Six percent used inefficient protective devices such as sunglasses.   Sixty one percent reported occasional exposure to welding flashes when not wearing any eye protection. Welding-related eye symptoms reported included foreign body sensation (18%), persistent after-images (31%), and watery eyes (50%).  Al- though the majority of the welders wore protective devices while welding, a few did not always use such devices while others used sunglasses for protection.  Moreover, many of the welders were occasionally, and only a few were always, exposed to welding flashes when protective devices were not used. Therefore, we concluded that eye protectionpractices amongst the welders appeared to be inadequate to avoid hazards associated with welding.  It is recommended that an eye protection educational campaign for welders should form part of the SouthAfrican Government’s workplace safety program

The impact of solar ultraviolet radiation on human health in sub-Saharan Africa

Photoprotection messages and ‘SunSmart’ programmes exist mainly to prevent skin cancers and, more recently, to encourage adequate personal sun exposure to elicit a vitamin D response for healthy bone and immune systems. Several developed countries maintain intensive research networks and monitor solar UV radiation to support awareness campaigns and intervention development. The situation is different in sub-Saharan Africa. Adequate empirical evidence of the impact of solar UV radiation on human health, even for melanomas and cataracts, is lacking, and is overshadowed by other factors such as communicable diseases, especially HIV, AIDS and tuberculosis. In addition, the established photoprotection messages used in developed countries have been adopted and implemented in a limited number of sub-Saharan countries but with minimal understanding of local conditions and behaviours. In this review, we consider the current evidence for sun-related effects on human health in sub-Saharan Africa, summarise published research and identify key issues. Data on the prevalence of human diseases affected by solar UV radiation in all subpopulations are not generally available, financial support is insufficient and the infrastructure to address these and other related topics is inadequate. Despite these limitations, considerable progress may be made regarding the management of solar UV radiation related health outcomes in sub-Saharan Africa, provided researchers collaborate and resources are allocated appropriately

Anti-UVC Irradiation and Metal Chelation Properties of 6-Benzoyl-5,7-dihydroxy-4-phenyl-chromen-2-one: An Implications for Anti-Cataract Agent

Coumarin derivative 1, 5,7-dihydroxy-6-(3-methyl-1-butyryl)-4-phenyl-chromen- 2-one, has been reported to possess radical scavenging activity and DNA protection. We have synthesized a series of coumarins with structural modifications at positions C4, C5, C6 and C7 and evaluated them for their anti-UVC properties. Coumarin 7, 6-benzoyl-5,6-dihydroxy-4-phenyl-chromen-2-one, was found to have the most potent activity in protecting porcine γ-crystallin against UVC insults. Results of fluorescence assays indicated that compound 7 was capable of decreasing the loss of intensity while lens crystallins and DNA PUC19 were irradiated with UVC. Presence of compound 7 decreased hydroxyl radical levels determined by probe 1b and the free iron concentrations determined by Ferrozine reagent. The chelation assay showed that compound 7 was chelated to metal via 6-CO and 5-OH on the benzopyrone ring. The observed protective effects of compound 7 towards crystallins from insults of UVC and free radicals may be due to its iron-chelating activity and its peak absorption at 254 nm

Optical effects of exposing intact human lenses to ultraviolet radiation and visible light

<p>Abstract</p> <p>Background</p> <p>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.</p> <p>Methods</p> <p>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.</p> <p>Results</p> <p>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.</p> <p>Conclusions</p> <p>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.</p

Tissue functions mediated by β3-adrenoceptors—findings and challenges

As β3-adrenoceptor agonists metamorphose from experimental tools into therapeutic drugs, it is vital to obtain a comprehensive picture of the cell and tissue functions mediated by this receptor subtype in humans. Human tissues with proven functions and/or a high expression of β3-adrenoceptors include the urinary bladder, the gall bladder, and other parts of the gastrointestinal tract. While several other β3-adrenoceptor functions have been proposed based on results obtained in animals, their relevance to humans remains uncertain. For instance, β3-adrenoceptors perform an important role in thermogenesis and lipolysis in rodent brown and white adipose tissue, respectively, but their role in humans appears less significant. Moreover, the use of tools such as the agonist BRL 37344 and the antagonist SR59230A to demonstrate functional involvement of β3-adrenoceptors may lead in many cases to misleading conclusions as they can also interact with other β-adrenoceptor subtypes or even non-adrenoceptor targets. In conclusion, we propose that many responses attributed to β3-adrenoceptor stimulation may need re-evaluation in the light of the development of more selective tools. Moreover, findings in experimental animals need to be extended to humans in order to better understand the potential additional indications and side effects of the β3-adrenoceptor agonists that are beginning to enter clinical medicine