Mature cataract

Oral administration of 1 g kg day in rabbits leads to lenticular changes, initially observed as swelling in the peripheral portion of the lens. Within 2 weeks, the whole lens is affected with mature cataract. The biochemical basis for cataract has been shown to be related to a liver metabolite of naphthalene, l,2-dihydro-l,2-dihydoxynaphthalene. 

Facilitating capsulotomy in mature cataracts with fluid lens material ... 

Exemplary applications of viscoelastic substances are in cases of mature cataract with liquefied lens cortex (compare Fig. 71). Should the mature lens be intumes-cent, high viscosity viscoelastic substances in the anterior chamber could supply the counter-pressure necessary to avoid, at least to a certain extent, an uncontrolled tearing of the anterior lens capsule, during capsulotomy (assuming that pressure within the lens capsule is not too high, since no one can possibly perform a capsulorhexis on a blown up, taught balloon). By driving back the milky-white, liquefied lens contents, viscoelastics, by virtue of their transparency, can achieve better optical conditions. 

Fig. 71. Viscoblockade may preserve capsular tension and maintain pressure in the capsular bag in case of a mature cataract with liquefied lens The viscoelastic substance is placed over the capsulorhexis/ capsulotomy to keep the liquefied lens contents from escaping. Visualization of the lens capsule is faci-liated and bad vision condition which are likely to appear when liquefied lens material mixes up with the aqueous humor is prevented...

Within a relatively short time triazin-treated albino and pigmented rats first developed cataracts in the posterior lens (suture) region. These lesions, which were rarely observed spontaneously, transformed dose-dependently into mature cataracts in the anterior cortex and whole lens in many cases. 

Barbizhayev, M. A. (2005). Analysis of lipid peroxidation and electron microscopic survey of maturation stages during human cataractogenesis Pharmacokinetic assay of Can-C N-acetylcamosine prodrug lubricant eye drops for cataract prevention. Drugs 6, 345-369. 

Lens aldose reductase has been implicated in the pathogenesis of cataracts in diabetic and galac-tosemic animals. The enzyme catalyzes the reduction of glucose and galactose to their polyols, which accumulate in large quantities in the lens and ultimately lead to mature lens opacities. Several key bioflavones have activity against this enzyme. Oral administration of quercitrin decreased the accumulation of sobital in the lens. Therefore, the accumulation of lens opacities could be partially abrogated by certain flavonoids. In a study of 30 flavones, 4 isoflavones, and 13 coumarins, many potent inhibitors were found, but 5,7,3, 4 -tetrahydroxy-3,6-dimethoxyflavone and 6,3, 4 -trihy-droxy-5,7,8-trimethoxyflavone were especially active. 

One of the most common causes of human blindness is cataract, the loss of lens transparency. The incidence of cataract increases dramatically with aging, and close to 50% of individuals over the age of 75 years have cataract (Leske and Sperduto, 1983). There are many different types of cataract, and for cataract of mature onset (senile cataract), there are likely to be many factors which eventually lead to the loss of lens transparency. Nevertheless, there is an accumulation of evidence which... 

In addition to posterior cataracts, 625 ppm dosed rats have also formed mature opacities in the anterior cortex and nucleus (Figures 21 and 25). 

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