Abstract. Cataract is a major ocular disease that causes blindness in many developing countries of the world. It is well established that various factors such as oxidative stress, UV, and other toxic agents can induce both in vivo and in vitro cataract formation. However, a common cellular basis for this induction has not been previously recognized. The present study of lens epithelial cell viability suggests such a general mechanism. When lens epithelial cells from a group of 20 cataract patients 12 to 94 years old were analyzed by terminal deoxynucleotidyl transferase (TdT) labeling and DNA fragmentation assays, it was found that all of these patients had apoptotic epithelial cells ranging from 4.4 to 41.8%. By contrast, in eight normal human lenses of comparable age, very few apoptotic epithelial cells were observed.We suggest that cataract patients may have deficient defense systems against factors such as oxidative stress and UV at the onset of the disease. Such stress can trigger lens epithelial cell apoptosis that then may initiate cataract development. To test this hypothesis, it is also demonstrated here that hydrogen peroxide at concentrations previously found in some cataract patients induces both lens epithelial cell apoptosis and cortical opacity. Moreover, the temporal and spatial distribution of induced apoptotic lens epithelial cells precedes development of lens opacification. These results suggest that lens epithelial cell apoptosis may be a common cellular basis for initiation of noncongenital cataract formation.
Chronic dacryocystitis is due to an obstruction in the nasolacrimal duct, with subsequent infection of the lacrimal sac. The goal of surgery is to reestablish intranasal drainage of the lacrimal sac. Classic dacryocystorhinostomy (DCR) requires an external incision and drilling through the lacrimal bone into the middle meatus. In our study a 600-micron neodymium:YAG (Nd:YAG) fiber with a blunt hemispherical tip is inserted via the lacrimal puncta. An intranasal ostium is created with the laser under intranasal endoscopic control. Silicon tubes are then left in place for 6 months. We have performed 49 procedures over the past 2 1/2 years, with a success rate of 85% after one surgical procedure, which is commensurate with standard DCR. This procedure provides a simple, bloodless, incisionless alternative to standard DCR.
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