Difference between Goldmann Applanation and Topcon Noncontact Tonometer Measurements after Excimer Laser Photorefractive Keratectomy

The authors' clinical experience has suggested that the noncontact tonometer (NCT) has a tendency to record a lower intraocular pressure(IOP) than the Goldmann applanation tonometer(GAT) after excimer laser photo refractive keratectomy(PRK). This study was done to verify this tendency. We performed PRK on 177 eyes of 122 patients using a VISX 20/20 excimer laser, and topical fluorometholone was used after PRK. The eyes were divided into three groups according to their ablation depths, and the IOP was measured with the GAT and the Topcon NCT before surgery and 1, 3, 6, 9, and 12 months postoperatively. The mean postoperative IOP measured with the GAT or the NCT decreased as compared with the mean preoperative IOP(GAT: 1.67 ~ 2.90 mmHg, NCT:5.27 ~ 6.54 mmHg). The mean NCT reading was 1.12 mmHg higher than the mean GAT reading preoperatively, but was 2.48 ~ 2.88 mmHg lower than the mean GAT reading postoperatively. Difference between GAT and NCT measurements postoperatively was more prominent in the group of deeper ablation. These results suggest that we should be cautious of evaluating the IOP measured with the GAT or the NCT after PRK.

Effect of Excimer Laser Photorefractive Keratectomy on Goldmann Applanation Tonometry

It can be speculated that the thinned and flattened central cornea after excimer laser photorefractive keratectomy (PRK) might give a falsely low Goldmann applanation tonometer(GAT) reading. We studied 353 eyes of 264 patients who underwent PRK to determine the effect of excimer laser PRK on the accuracy of Goldmann applanation tonometry. PRK was done with a VISX 20/20 excimer laser and topical fluorometholone was used after PRK. The intraocular pressure(IOP) was measured with the GAT before surgery and 1, 3, 6, 9, and 12 months postoperatively. The mean ablation depth of the cornea was 71.4 +/- 22.0 micrometer, and the eyes were divided into three groups according to their ablation depths. The mean postoperative IOP measured with the GAT decreased as compared with the mean preoperative IOP(P<0.01). The mean postoperative IOP at 9 or 12 months was lower than that at 1, 3, or 6 months(p<0.05). The mean IOP(11.9 +/- 2.5 mmHg) at 12 months was 2.8 mmHg lower than the mean preoperative IOP(14.7 +/- 2.7 mmHg). There was no statistically significant difference in the amount of postoperative IOP decrease among the three groups.

Clinical Characteristics of Electric Cataract

To evaluate the various factors related to the development of electric cataract in electric burn patients, we reviewed medical charts of 663 electric burn patients who were admitted to the department of General Surgery in Hanil General Hospital between 1981 and 1993. Eleven patients(1.7%) had electric cataract in both eyes. All of them were injured by contact with 22,900 voltage current, and developed third degree burns. Fifty-eight electric burn patients had their electric inputs through their head and eight (13.8%) among them developed cataracts. Only three(0.5%) among 567 electric burn patients who had their electric inputs through upper extremities developed cataracts. The interval between the electric injury and the diagnosis was 2 to 18 months. Anterior subcapsular opacity was the most common type of lenticular opacity. Other associated ocular complications included uveitis, macular edema, macular degeneration, and macular hole.

Excimer laser photorefractive keratectomy for astigmatism

The effectiveness of excimer laser photorefractive keratectomy (PRK) for astigmatism was evaluated. We treated 136 eyes of naturally occurring myopic astigmatism using the 193-nm excimer laser with an expanding slit and an iris diaphragm, and followed for a minimum of 6 months. At 6 months after operation, the mean refractive cylinder decreased from 1.62 +/- 0.88 D preoperatively to 0.48 +/- 0.48 D. For detailed analysis of the results, the surgically induced refractive change (SIRC) was determined from the preoperative and postoperative refractions by vector analysis of astigmatism. When we compared the cylinder of the SIRC with the preoperative refractive cylinder, the effect of the cylindrical ablation was 93.9 +/- 36.7% at 6 months. The axial error of the cylinder of the SIRC to the preoperative cylindrical axis was 5.9 +/- 10.2 degrees at 6 months. These results suggest that excimer laser PRK with an expanding slit appears to have a significant effect for the correction of astigmatism.

Prevalence of intestinal parasites in Korea

A survey of intestinal parasites infection among Korean people has been carried out during July 1969 to December 1970. A total of 2,250 stool specimens (male 1,101, female 1,146) was collected from all the provinces and Seoul city in Korea. The specimens were examined routinely by direct fecal smear, zinc sulfate flotation and formalin-ether sedimentation techniques. The results are summarized as follows: Of 2,250 specimens examined, l,803(80.l per cent) were positive for intestinal parasites. The positive rates of intestinal helminths were 1,644(73.1 per cent) among 2,250; Ascaris lumbricoides 46.0 per cent, Trichocephalus trichiurus 46.8 percent, hookworm 6.8 per cent, Trichostrongylus orientalis 7.0 percent, Clonorchis sinensis 12.1 percent, Enterobius vermicularis 1.6 per cent, Hymenolepis nana 0.7 percent, Taenia species 0.3 per cent, Metagonimus yokogawai 0.04 percent, Fasciolidae 0.04 per cent and one case of lung fluke Paragonimu westermani. The positive rstes of intestinal protozoa were 786(34.9 per cent); Entamoeba histolytica 6.4 per cent, Entamoeba coli 20.5 percent, Endolimax nana 10.0 per cent, Giardia lamblia 5.1 per cent, Trichomonas hominis 1.1 percent, Chilomastix mesnili 0.5 percent, Iodamoeba butschlii 0.6 percent, Enteromonas hominis 0.7 percent, Dientamoeba fragilis 0.1 per cent and one case of Isospora hominis. Sexual distribution of helminths and protozoan infections showed higher rate in female than that of male, except C. sinensis, H. nana, Taenia species or G. lamblia Infections of T. trichiurus, hookworm, T. orientalis, C. sinensis, Taenia species, E. histolytica, E. coli and E. nana increased with age. Conversely, H. nana and G. lamblia infections were more predominent in younger ages.