Influence of experimental uveitis on the rabbit lens

Cataract as a complication of severe microbial keratitis

Complicated cataract results from local ocular disease; we report five cases that followed severe anterior segment infection. Three patients had Pseudomonas keratitis and two Acanthamoeba keratitis. All patients had severe keratitis and iridocyclitis. Mature cataracts developed after a mean of 5.5 months from the onset. Cataract formation with severe keratitis may be attributable to bacterial toxins, iridocyclitis and treatment toxicity. All these factors may cause cataract by interference with lens metabolism. One of our cases had no steroid treatment; the remaining four had between 7.7 and 28.14 mg of topical steroid (256-938 drops of Dexamethasone 0.1%). Cataract formation may result from severe microbial keratitis alone but is probably enhanced by concurrent treatment with high doses of topical steroid. The potential for cataract formation must be considered when managing microbial keratitis with the use of steroids and when planning surgical rehabilitation of the anterior segment.

In vitro effect of alpha-tocopherol on lysophosphatidylcholine-induced lens damage

Lysophosphatidylcholine (LPC) has been shown to be toxic to the lens in organ culture. An investigation into whether vitamin E counteracts the in vitro damaging effect of LPC on rat lenses was undertaken. A concentration higher than 10 micrograms ml-1 LPC in the culture medium is necessary to damage rat lenses, as assessed by protein content of the medium and Na+ and K+ content of the lens. Vitamin E affords its protection when present at a concentration of 10(-3) M: both the protein efflux from the lens and the lenticular cation imbalance are prevented, also if LPC concentration is 100 micrograms ml-1. This effect may be due more to the physicochemical properties of vitamin E in the stabilization of biological membranes, than to its chemical behaviour as an antioxidant.