Effects of Multicurve RGP Contact Lens Use on Topographic Changes in Keratoconus

PURPOSE: To evaluate the effects of wearing rigid gas permeable (RGP) contact lenses on the topographic changes in keratoconus. METHODS: Seventy-seven keratoconic eyes that wore multicurve RGP contact lenses and 30 keratoconic eyes that wore no contact lenses were retrospectively analyzed. The mean follow-ups were 22.6 and 20.5 months in the lens-wearing and control groups, respectively. Visual acuity, comfort, daily wearing time, and corneal staining were evaluated for both groups. The changes in topographic indices were compared between the lens-wearing and control groups. RESULTS: Multicurve RGP lens corrected logarithm of the minimum angle of resolution visual acuity of the lens-wearing group significantly improved from -0.016+/-0.065 to -0.032+/-0.10 at follow-up (p=0.05). In the lens-wearing group with advanced keratoconus, the Sim Kmax, Sim Kmin, apical power, astigmatic index, and anterior elevation significantly decreased from 57.68+/-4.26 diopter (D), 50.50+/-2.32 D, 62.79+/-5.11 D, 7.20+/-0.55 D and 67.36+/-16.30 microm to 55.51+/-4.28 D, 49.62+/-3.26 D, 60.31+/-5.41 D, 5.90+/-0.51 D and 60.61+/-16.09 microm, respectively (paired t-test, p<0.05). The irregularity index of 3 mm did not significantly change. Meanwhile, in the control group, the apical power and irregularity index increased from 55.56+/-7.25 D and 3.06+/-1.68 D to 57.11+/-7.75 D and 3.25+/-1.71 D, respectively (paired t-test, p=0.008, p=0.01). CONCLUSIONS: Properly fitted multicurve RGP contact lenses are not likely to contribute to the progression of keratoconus.

Comparison of The IOL Master(R) and A-scan Ultrasound: Refractive Results of 96 Consecutive Cases

PURPOSE: To study the refractive outcome of cataract surgery employing partial coherence interferometry (PCI) and to compare this outcome with that of A-scan ultrasound in a prospective study of 96 eyes of 96 patients that underwent phacoemulsification with intraocular lens (IOL) implantation. METHODS: The SRK-T formula was employed, using PCI (IOL Master(R): the only commercially available model) and A-scan ultrasound data, to predict patients' implanted IOL power. Four to six weeks after cataract surgery, the refractive outcome was determined, and results from the two different biometry methods were compared. RESULTS: Ninety-six patients (mean age: 67.64, SD: 9.91) underwent phacoemulsification with IOL implantation. The optical axial length obtained using the IOL Master(R) was significantly longer (p<0.001, Student's t-test) than the axial length obtained via by A-scan ultrasound, 24.29 (SD 1.80) mm vs. 24.19 (1.75) mm. When using the IOL Master(R), the mean prediction error (PE; planned target of refraction - postoperative refraction) was 0.30 (0.60) D, and the mean absolute prediction error (APE) was 0.51 (0.44) D. When using A-scan ultrasound, the mean PE was 0.01 (0.64) D, and the mean APE was 0.47 (0.43) D. The difference in mean APE between the two biometry methods was not statistically significant (p=0.236, Wilcoxon signed rank test). Among the eyes with an axial length greater than 25 mm, as determined by A-scan ultrasound, the difference in the mean APE was not statistically significant (0.48 (0.87) vs. 0.58 (0.61), p=0.094). Likewise, among the eyes for which with axial length measured by A-scan ultrasound longer than IOL Master(R), the difference in the mean APE error was not statistically significant, (0.33 (0.30) vs. 0.46 (0.41), p=0.110). CONCLUSIONS: IOL power calculation using the PCI is as accurate as that using A-scan ultrasound for predicting the postoperative refractive state of patients who have undergone cataract surgery.

Clinical Characteristics of Leber's Congenital Amaurosis in Korea

PURPOSE: To study the clinical characteristics and visual prognosis of Leber's congenital amaurosis in Korea. METHODS: Children who were diagnosed with Leber's congenital amaurosis at Seoul Natioanl University Children's Hospital between 1992 and 2004, were included in this study. The medical records pertaining to the clinical characteristics and visual outcomes of the patients were retrospectively reviewed. RESULTS: The mean age of the patients at presentation and during the subsequent follow-up period was 15.5 and 62.7 months, respectively. The principal symptoms included lack of fixation (69.0%) and nystagmus (23.8%). At first observation, nystagmus was found in 40 patients, and the appearance of the fundi were variable, including 'normal' (23.8%), pigmentary degeneration (54.8%), vascular attenuation (35.7%) and macular coloboma (19.0%). At the age of three to five years, 44.4% of patients had hyperopia greater than +5D. At the time of last follow-up, the visual acuities of the patients who were examined after the age of four were 'hand motion' in 68.7%, > or =20/400 in 9.4%. No patient had visual acuity better than 20/200. Eight (25%) patients could read with glasses or low-vision aids. CONCLUSIONS: The visual prognosis of patients with Leber's congenital amaurosis was poor in most cases, but a majority of our patients displayed a stable clinical course. Progression was rare, and one fourth of the patients were able to read with appropriate aides. In conclusion, regular follow-up care to assess visual function is necessary for optimal outcomes.

Clinical Characteristics of Leber's Congenital Amaurosis in Korea

PURPOSE: To study the clinical characteristics and visual prognosis of Leber's congenital amaurosis in Korea. METHODS: Children who were diagnosed with Leber's congenital amaurosis at Seoul Natioanl University Children's Hospital between 1992 and 2004, were included in this study. The medical records pertaining to the clinical characteristics and visual outcomes of the patients were retrospectively reviewed. RESULTS: The mean age of the patients at presentation and during the subsequent follow-up period was 15.5 and 62.7 months, respectively. The principal symptoms included lack of fixation (69.0%) and nystagmus (23.8%). At first observation, nystagmus was found in 40 patients, and the appearance of the fundi were variable, including 'normal' (23.8%), pigmentary degeneration (54.8%), vascular attenuation (35.7%) and macular coloboma (19.0%). At the age of three to five years, 44.4% of patients had hyperopia greater than +5D. At the time of last follow-up, the visual acuities of the patients who were examined after the age of four were 'hand motion' in 68.7%, > or =20/400 in 9.4%. No patient had visual acuity better than 20/200. Eight (25%) patients could read with glasses or low-vision aids. CONCLUSIONS: The visual prognosis of patients with Leber's congenital amaurosis was poor in most cases, but a majority of our patients displayed a stable clinical course. Progression was rare, and one fourth of the patients were able to read with appropriate aides. In conclusion, regular follow-up care to assess visual function is necessary for optimal outcomes.

Clinical Analysis of Herpetic Keratitis in Korea

PURPOSE: To investigate the clinical characteristics of herpetic keratitis in Korea. METHODS: A retrospective analysis was performed on 90 eyes of 84 patients who were clinically diagnosed with herpetic keratitis and were followed for at least 4 months or more. Information on prior herpetic keratitis, type of keratitis, time to remission, recurrence rate, administration of oral acyclovir, final visual acuity was reviewed. Remission time and recurrence rate were compared according to types of herpetic keratitis and the application of oral acyclovir in epithelial, stromal or endothelial keratitis; and the relation of history of previous herpetic keratitis, recurrence and final vision, was analyzed. RESULTS: Sex ratio (M:F) was 1.31 and the mean age was 54.6 years. Of 90 eyes, the proportion of infectious epithelial keratitis, stromal keratitis, endothelitis and neurotrophic ulcer was 51.1, 17.8, 25.6 and 5.6%, respectively. The mean remission time was 1.92+/-1.01, 4.13+/-5.05, 5.52+/-5.08, 4.00+/-1.00, respectively (p=0.001, one-way Anova). Recurrence occurred in 21 (42.9%) eyes of 49, which were followed up for more than 12 months, in a year after the previous attack. The rates of recurrence of infectious epithelial keratitis, stromal keratitis and endothelitis were 25.0%, 63.6% and 53.8%, respectively. Oral acyclovir neither shortens the remission nor prevents the recurrence. The percentage of final vision over 20/40 in infectious epithelial keratitis, stromal keratitis and endothelitis was 81.1, 57.1 and 60.0%, respectively. The final vision was worse in the group with a history of herpetic keratitis. CONCLUSIONS: Stromal keratitis and endothelitis showed a higher recurrence rate and longer remission time than infectious epithelial keratitis. Because recurrent and severe keratitis may result in corneal opacity and vision loss, aggressive and proper treatment is needed. However, these cases are often resistant to therapy.

A Case of Low Vision Device Application in a Patient with Visual Acuity Counting Fingers

PURPOSE: To report the successful application of a Keplerian telescope in a low vision patient whose visual acuity was counting fingers, which is typically a difficult range for LVA adaptation. METHODS: We used telescopes, distance low vision devices, in a 36-year-old man whose visual acuity, because of congenital corneal opacity, was limited to hand movement in his left eye and to counting fingers in his right eye. The objective was to improve his ability to participate in outdoor activities. RESULTS: Even though the patient's visual acuity was seemingly beyond improvement, his visual acuity was improved to the level of 20/100 with a distance low vision device, a Keplerian telescope 8 x 30. CONCLUSIONS: In the case of patients whose visual acuity is worse than counting fingers, it is usually difficult to improve poor vision by using telescopes for distance. However, in spite of restricted adaptation, low vision telescopes can be used to produce good results in low vision patients.