Preliminary evaluation of a simple photographic cataract classification for epidemiological surveys

Synthesis of 4-hydroxy-3(2H)-furanone acyl derivatives and their anti-cataract effect on spontaneous cataract rats (ICR/f)

4-Hydroxy-2,5-dimethyl-3(2H)-furanone (HDMF) and 2(or 5)-ethyl-4-hydroxy-5(or 2)-methyl-3(2H)-furanone (EHMF) are known to inhibit cataract development in spontaneous cataract rats (ICR/f). Forty-five acylated hydroxyfuranone derivatives were designed and synthesized for an anti-cataract test, and their hydrophobic constants were also tested. Among these derivatives, 2,5-dimethyl-4-pivaloyloxy-3(2H)-furanone (HDMF pivalate) exerted a marked protective effect against the development of cataract in a galactose-induced model using cultured rat lens (in vitro). When tested on an ICR/f cataract model (in vivo), HDMF pivalate showed more significant inhibition of cataract development than parent compound HDMF. This derivative is more lipophilic than HDMF, so that HDMF pivalate can penetrate the cornea more easily than HDMF. The inhibition of cataract development by HDMF converted from HDMF pivalate is supported by the fact that HDMF was observed in the lens of ICR/f rats treated with HDMF pivalate.

Antioxidative activities of 4-hydroxy-3(2H)-furanones and their anti-cataract effect on spontaneous cataract rat (ICR/f)

We determined the anti-cataract effects and antioxidative activities of four 4-hydroxy-3(2H)-furanones. These four furanones showed similar antioxidative activities in the ferric ion reduction model. 4-Hydroxy-2,5-dimethyl-3(2H)-furanone (HDMF) and 2(or 5)-ethyl-4-hydroxy-5(or 2)-methyl-3(2H)-furanone (EHMF) exhibited a higher suppression effect on lipid peroxidation in human plasma than the other furanones did. The effects of hydroxy furanones on the onset of cataract in spontaneous cataract rat (ICR/f rat) were tested, and it was observed that HDMF and EHMF inhibited cataract formation. These results suggest that the antioxidative activity of HDMF and EHMF against superoxide radicals in lens tissue contributed to inhibiting the onset of spontaneous cataract.

Sunlight exposure, antioxidant status, and cataract in Hong Kong fishermen

STUDY OBJECTIVES

The aim was to test whether cataract is associated with higher lifetime exposure to sunlight, and whether antioxidants protect against cataract.

DESIGN

This was a cross sectional survey of eye disease, with assessment of antioxidant status in a subgroup.

SETTING

Hong Kong fishing communities in 1989.

PARTICIPANTS

685 men and women aged 55 to 74 years old were included in the study, of whom 367 (54%) attended hospital for detailed examination.

MEASUREMENTS AND MAIN RESULTS

At a mobile clinic visual acuity and lens opacities were assessed, and using a questionnaire, occupational history and lifetime exposure to sunlight. At hospital ophthalmic measurements were repeated and blood was taken for measurement of plasma vitamin C, vitamin E, and total carotenoids, and red cell activities of glucose-6-phosphate dehydrogenase, glutathione peroxidase, superoxide dismutase, and catalase. Higher grades of cataract (particularly nuclear cataract) tended to be more common in subjects with the most sun exposure, although not to the point of statistical significance. In contrast to earlier studies, no association was found with antioxidant status.

CONCLUSIONS

The findings give some support to the hypothesis that sunlight causes cataract. The absence of a relation to antioxidant status may be because blood levels of antioxidants at one point in time do not adequately reflect a subject's past metabolic state, and particularly the past activity of antioxidants in the lens.

Suitability of slit lamp retroillumination photographs for classifying cataracts according to 'Lens Opacities Classification System II (LOCS II)'

The Lens Opacities Classification System II (LOCS II) utilizes photographic standards (two retroilluminated Neitz-CTR and one standard slit lamp Zeiss photographs) for the classification of cortical and posterior subcapsular cataracts, nuclear color and nuclear opalescence. However, dedicated photographic devices, particularly retroillumination cameras, are not always available and this study was aimed at evaluating the suitability of a retroillumination photographic technique with a standard slit lamp camera for cortical and posterior subcapsular cataract classification according to LOCS II. Two observers examined 273 eyes. Kappa statistics demonstrated that agreement between the standard slit lamp, clinical grading (according to published LOCS II methodology) and photographic grading (according to our photographic technique), as well as inter- and intraobserver reproducibility, were excellent (Kappa > 0.74) for the classification of all lenticular regions. The results indicate that a standard slit lamp camera can be as useful as a dedicated retroillumination camera when LOCS II standards are used for cataract classification.