With the advent of improved methods of aseptic technique in ophthalmic surgery, many excellant antiseptics were introduced into presurgical skin preparation. Some of these antiseptics with synthetic detergent, however, are known to be toxic to the cornea.
In this study of the corneal toxicity, twenty five rabbits(50 eyes) were used-they were divided into 5 groups and each group included 10 eyes. The 5 different antiseptics-10% Potadine solution(povidone-iodine without detergent), 7.5% Potadine scrub(povidone-iodine with detergent), 1% TEGO 103G, 70% ethanol, and normal saline-were separately instilled into the conjunctival sac of rabbits in each group, and then the corneal change was observed at 30 minutes, 3 hours, 1 day, 2 days, 3 days, and 7 days after the application. The auther evaluated the toxic effect of these solutions by corneal pachymetry, biomicroscopy with fluorescein staining, and electron microscopy.
The results were as followings: Before application of these solutions, the mean of central corneal thickness was 0.4180.019mm(S.D.). In the group with Potadine solution and the control group with normal saline, there were no changes in corneal thickness and epithelium. In the group with 1% TEGO 103G, after one day there was moderate corneal swelling, and after 2 days the corneal thickness returned to normal. In the groups with Potadine scrub and with 70% ethanol, it was found to have marked swelling and deepitheliazation until the third day. The most prominent toxic change of cornea was shown one day after application. All corneas had returned to normal by 7 days.
In the groups with Potadine solution and with 1% TEGO 103G, light and electron microscopic findings showed no significant changes in comparison with control group and normal rabbit. In the groups with Potadine scrub and with 70% ethanol, after 30 minutes light microscopic examination revealed partial desquamation of superficial layer, and after 3 hours complete exfoliation. After 30 minutes electron microscopic finding showed that perineuclear cisterna, cisternae of rough endoplasmic reticulum(RER) and Golgi apparatus, and intercellular space appear to be narrow in comparison with those of normal ones. Autosomes were noticeable in the electron lucent cytoplasm of corneal epithelium.
This study revealed that povidone-iodine solution without detergent and 1% TEGO 103G (alnphoteric surfactant) have minimal corneal toxicity whereas povidone-iodine surgical scrub with detergent and 70% alcohol are very toxic to the cornea.
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