The Clinical Feature of Keratoconus in Korean

This study was performed to evaluate epidemiology and progression of keratoconus in Korean. 122 patients(223 eyes)who visited Kang-Nam St.Mary's Hospital and Bu-Pyung our lady of mercy hospital with keratoconus from 1989 to 1998 were reviewed retrospectively. At the time of diagnosis, prevalence in male(75 patients)was greater than that in female(47 patients)and the rate bilateral involvement was 84.4%(103 patients). The average age was 18.33+/-6.79 years and there is no difference between that of male and female. The greatest number of patients(63 patients, 51.6%)had been diagnosed from 15 to 24 years old. The mean astigmatism was 3.92+/-1.91 diopters. Of the 19 patients with unilateral keratoconus, 10 patients were followed up over three years(average follow period: 61months)and four reported that the disease had later been diagnosed in the contralateral eye. The greatest number of patients(107 eyes, 47.9%)had been examined from 0.02 to 0.1 in visual acuity without correction and 58 eyes(26.0%)achieved visual acuity with hard contact lens correction. Corneal findings included thinning(158 eyes), scarring(62 eyes), Fleischer ring(119 eyes), Vogt's striae(78 eyes). On corneal topography, a half of apex of cone(57 eyes of 107 eyes, 53.2%)was located in inferior temporal quadrant and highest rate of steepening(corneal power change away from the apex to the periphery along its semimeridian)was 2.70+/-1.48 diopters.

Accuracy of Intraocular Lens Power in Cataract Patients Underwent Excimer Laser PRK

We retrospectively evaluated postoperative refraction of four patients(five eyes)who received intraocular lens implantation after excimer laser photorefractive keratectomy (PRK).The mean age of the patients was 44.8 years and 3 patients were female and 1 patient was male.The mean interval between PRK and cataract operation was 20.2 months (1 to 45 months)and the mean follow-up time after cataract operation was 16.2 months(2~43months).Phacoemulsification and PMMA-PCL(6.0~6.5 mm)implantation were made in all cases.SRK-II formula,the most popular empirical formula was used in first 3 cases(group I),but Idem-lens formula,a primitive theoretical formula was used in another 2 cases (group II)after occurrence postoperative refraction errors in group I .In group I and II,the mean postoperative refraction error was +3.00 diopters and +0.50 diopters and uncorrected visual acuity at postoperative 2 months was 20/60 and 20/24 respectively.The mean of calculated IOL-power was -3.75 diopter in group I and -0.625 diopter in group II.From these results,the empirical formula is definitely unsuitable for the calculation of IOL power in the cataract operation following excimer laser PRK. Moreover,although a primitive one,Idem-lens theory could be temporally useful for the IOL-power calculation in such cases.In conclusion,new formula is required for the cataract operation following excimer laser PRK.