RÉSUMÉ
BACKGROUND:Posterior capsulotomy with Nd-YAG laser is the main method in clinic for the treatment of after-cataract, but it often damages the intraocular lens during the treatment. OBJECTIVE:To research the effect of Nd-YAG laser damage on the intraocular lens optical properties based on the laboratory testing. METHODS:Ten hydrophobic acrylic intraocular lenses were col ected as the test samples, and then Nd-YAG laser with the pulse energy of 5.0 mJ was used for 50 single-pulse laser shooting on the center of a circle with the diameter of 3 mm on the back surface of each sample. The shapes of the damaged area on the samples were observed under scanning electron microscope after laser shooting. Optical analyzer was used to test the average optical power and optical power distribution. RESUTLS AND CONCLUSION:The intraocular lenses were observed under scanning electron microscope under 40 times and 1 000 times enlargement and showed that there was circle-like depression with the diameter about 50μm on the back surface of the intraocular lenses, and there was protruding around the depression. Intraocular lens optical analyzer test results showed that there was no significant change in the average optical power of intraocular lenses after laser damage, but the optical power distribution was changed significantly. In the center of the circle with the diameter of 3 mm, the optical power showed annular distribution radiating to the surrounding tissue with the center of circle-like depression area. The Nd-YAG laser damage has less effect on the optical power, but has great effect on the optical power distribution of intraocular lenses.
RÉSUMÉ
Sulfadizine when given in a small dose (250 mgms. 3 times a day) for a certain period of time (6 months) appears to produce subjective and objective improvements in patients with senile cataract. This work further (on-firms similar observations by the German workers Hackmann and Hackmann. The possible mechanism of the phenomena is predicted to be related to the enzyme contents of the lens, probably the carbonic anhydrase. (Conclusion)