Eun Chul Kim

A Comparison of Vitamin A and Cyclosporine A 0.05% Eye Drops for Treatment of Dry Eye Syndrome

PURPOSE To compare the efficacy of vitamin A (retinyl palmitate) and cyclosporine A 0.05% eye drops in treating patients with dry eye disease. DESIGN Prospective, randomized, controlled, parallel group study. METHODS A total of 150 patients with defined dry eye disease participated (50 in each treatment group). In 3 identical clinical trials, patients were treated twice daily with cyclosporine A 0.05%, or four times daily with retinyl palmitate 0.05%, or with neither cyclosporine or retinyl palmitate. Adjunctive treatment with preservative-free artificial tears was undertaken four times daily in all 3 groups. Corneal fluorescein staining results, Schirmer tear test (without anesthesia) results, tear film break-up time (BUT), dry eye symptom score, and impression cytologic analysis results were obtained before treatment and at the first, second, and third months after initiation of treatment. RESULTS Both vitamin A eye drops and topical cyclosporine A 0.05% treatments led to significant improvement in blurred vision, tear film BUT, Schirmer I score results, and impression cytologic findings in patients with dry eye syndrome (P < .05) compared to the control group treated with preservative-free artificial tears alone. CONCLUSIONS Both vitamin A eye drops and topical cyclosporine A 0.05% treatments are effective for the treatment of dry eye disorder.

Prevalence and risk factors for refractive errors: Korean National Health and Nutrition Examination Survey 2008-2011.

Purpose To examine the prevalence and risk factors of refractive errors in a representative Korean population aged 20 years old or older. Methods A total of 23,392 people aged 20+ years were selected for the Korean National Health and Nutrition Survey 2008–2011, using stratified, multistage, clustered sampling. Refractive error was measured by autorefraction without cycloplegia, and interviews were performed regarding associated risk factors including gender, age, height, education level, parents education level, economic status, light exposure time, and current smoking history. Results Of 23,392 participants, refractive errors were examined in 22,562 persons, including 21,356 subjects with phakic eyes. The overall prevalences of myopia (< -0.5 D), high myopia (< -6.0 D), and hyperopia (> 0.5 D) were 48.1% (95% confidence interval [CI], 47.4–48.8), 4.0% (CI, 3.7–4.3), and 24.2% (CI, 23.6–24.8), respectively. The prevalence of myopia sharply decreased from 78.9% (CI, 77.4–80.4) in 20–29 year olds to 16.1% (CI, 14.9–17.3) in 60–69 year olds. In multivariable logistic regression analyses restricted to subjects aged 40+ years, myopia was associated with younger age (odds ratio [OR], 0.94; 95% Confidence Interval [CI], 0.93-0.94, p < 0.001), education level of university or higher (OR, 2.31; CI, 1.97–2.71, p < 0.001), and shorter sunlight exposure time (OR, 0.84; CI, 0.76–0.93, p = 0.002). Conclusions This study provides the first representative population-based data on refractive error for Korean adults. The prevalence of myopia in Korean adults in 40+ years (34.7%) was comparable to that in other Asian countries. These results show that the younger generations in Korea are much more myopic than previous generations, and that important factors associated with this increase are increased education levels and reduced sunlight exposures.

The Inhibitory Effects of Bevacizumab Eye Drops on NGF Expression and Corneal Wound Healing in Rats

PURPOSE To investigate the effect of bevacizumab eye drops on corneal epithelial wound healing in rats. METHODS One hundred twenty Sprague-Dawley male rat corneas were divided into two groups and de-epithelized with a microblade. The bevacizumab group was treated with 5% bevacizumab and antibiotic 0.5% levofloxacin eye drops four times daily and the control group with antibiotic eye drops only. Corneal wound healing was evaluated by fluorescein staining at initial wounding and 24, 48, and 72 hours after epithelial debridement. Nerve growth factor (NGF) and vascular endothelial growth factor (VEGF) proteins were measured in rat corneas by ELISA. Immunofluorescent staining for NGF and VEGF was performed in rat corneas. NGF mRNA and VEGF mRNA was measured in rat corneas by real-time PCR. RESULTS The corneal wound healing rate was decreased in the bevacizumab group compared with that in the control group. Twenty-four, 48, and 72 hours after epithelial debridement, corneal NGF and VEGF proteins in the bevacizumab group were lower than that in the control group (P<0.05). Immunofluorescent staining showed that NGF and VEGF expression was stronger in the control group than in the bevacizumab group. NGF mRNA and VEGF mRNA levels in the bevacizumab group were also lower than in the control group (P<0.05). CONCLUSIONS After corneal epithelial damage, VEGF and NGF increased normally in the rat corneas. In contrast, when VEGF was inhibited by bevacizumab eye drops, the wound healing rate was decreased, and NGF was downregulated. Bevacizumab eye drops have an inhibitory effect on corneal wound healing in rats.

Microincision versus small-incision coaxial cataract surgery using different power modes for hard nuclear cataract

PURPOSE: To compare the efficacy of microincision and small‐incision coaxial phacoemulsification in treating hard cataracts using different ultrasound power modes. SETTING: Department of Ophthalmology, Seoul St. Marys Hospital, College of Medicine, Catholic University of Korea, Seoul, Korea. DESIGN: Randomized clinical trial. METHODS: Eyes with hard cataract were randomized to have an initial incision of 1.80 mm, 2.20 mm, or 2.75 mm. The eyes in each group were equally randomized to treatment with burst, pulse, or continuous mode. Ultrasound time (UST), mean cumulative dissipated energy (CDE), corrected distance visual acuity (CDVA), surgically induced corneal astigmatism, incisional and central corneal thickness (CCT), and endothelial cell counts were evaluated. RESULTS: The study enrolled 180 eyes, 60 in each group. Two months postoperatively, there were no statistically significant differences in UST, CDE, CDVA, CCT, or percentage endothelial cell loss between the 3 incision groups. The 2.75 mm incision induced more astigmatism at 2 months and less incisional corneal edema at 1 week than the 1.80 mm or 2.20 mm incision (P<.05). The UST, CDE, incisional corneal thickness, and CCT at 1 week and the percentage endothelial cell loss at 2 months with continuous mode were statistically significantly higher than with pulse mode and burst mode in all 3 incision groups (P<.05). CONCLUSIONS: Phacoemulsification using microincisions may be as safe and effective as the conventional small incision for hard cataract. The intraoperative energy use and ocular damage was less with the pulse and burst modes than with the continuous mode. Financial Disclosure: No author has a financial or proprietary interest in any material or method mentioned.

Inverse Relationship Between High Blood 25-Hydroxyvitamin D and Late Stage of Age-Related Macular Degeneration in a Representative Korean Population

PURPOSE To investigate the association of 25-hydroxyvitamin D with AMD. METHODS A population-based, cross-sectional study using a nationwide, systemic-stratified, multistage-clustered sampling method involved a total of 17,045 subjects older than 40 years who participated in the Korean National Health and Nutrition Examination Survey 2008 to 2012. All participants underwent standardized interviews, evaluation of blood 25-hydroxyvitamin D levels, and comprehensive ophthalmic examinations. A 45° digital fundus photograph of both eyes was taken under physiologic mydriasis. All fundus photographs were graded using the international classification and grading system. RESULTS Blood 25-hydroxyvitamin D levels were 17.5 ng/mL in women and 20.0 ng/mL in men. After adjusting for potential confounders including age, sex, smoking status, hypertension, heart problems, stroke, and sunlight-exposure time, the odds ratio (OR) for late AMD significantly decreased in the highest blood 25-hydroxyvitamin D quintile (OR, 0.32; 95% confidence interval [CI], 0.12-0.81; P for trend = 0.018) compared with the lowest quintile in men, but not in women. Early AMD was not associated with blood 25-hydroxyvitamin D levels in either sex. CONCLUSIONS High level of blood 25-hydroxyvitamin D was inversely associated with late AMD in men but not women. Considering antiangiogenic and antifibrotic action of vitamin D, association between two variables warrants further studies.

Comparison of phaco-chop, divide-and-conquer, and stop-and-chop phaco techniques in microincision coaxial cataract surgery

Purpose To compare the outcomes of coaxial microincision cataract surgery (MICS) performed with 3 phacoemulsification techniques (phaco‐chop, divide‐and‐conquer, and stop‐and‐chop) according to cataract density. Setting Bucheon St. Mary’s Hospital, College of Medicine, Catholic University of Korea, Seoul, South Korea. Design Prospective randomized clinical trial. Methods Eyes with nuclear density from grade 2 to 4 were randomly subdivided into 3 groups (phaco‐chop, divide‐and‐conquer, and stop‐and‐chop). Intraoperative measurements included ultrasound time (UST), mean cumulative dissipated energy (CDE), and balanced salt solution use. Clinical measurements included preoperative and 1 day, 1 month, and 2 month postoperative corrected distance visual acuity, central corneal thickness, and endothelial cell count. Results Intraoperative measurements showed significantly less UST, CDE, and balanced salt solution use with the phaco‐chop technique than with the divide‐and‐conquer and stop‐and‐chop techniques in the grade 4 cataract density group (P<.05). The percentage of endothelial cell loss was significantly lower in the phaco‐chop group than in the divide‐and‐conquer and stop‐and‐chop groups in the grade 4 cataract density group 2 months after cataract surgery (P<.05). Conclusions All 3 techniques may be effective for coaxial MICS in mild and moderate cataracts. However, in eyes with hard cataract having coaxial MICS, the phaco‐chop technique can be more effective for lens removal, with less corneal endothelial damage, than the divide‐and‐conquer and stop‐and‐chop techniques. Financial Disclosure No author has a financial or proprietary interest in any material or method mentioned.

Comparison of treatment with preservative-free versus preserved sodium hyaluronate 0.1% and fluorometholone 0.1% eyedrops after cataract surgery in patients with preexisting dry-eye syndrome

Purpose To compare treatment with preservative‐free and preserved sodium hyaluronate 0.1% and fluorometholone 0.1% eyedrops after cataract surgery in patients with preexisting dry‐eye syndrome. Setting Bucheon St. Mary’s Hospital, Catholic University of Korea, Seoul, Korea. Design Randomized controlled study. Methods Patients with cataract and dry‐eye syndrome were randomly divided into 2 groups. Group 1 patients were treated with preservative‐free sodium hyaluronate 0.1% and preservative‐free fluorometholone 0.1% eyedrops 4 times a day in the first month and twice a day in the second month. Group 2 patients were treated with preserved eyedrops using the same schedule. Ocular Surface Disease Index (OSDI) score, tear‐film breakup time (TBUT), Schirmer I test, corneal fluorescein staining, impression cytology, and antioxidant and inflammatory cytokine activities in tears were evaluated. Results Both groups comprised 40 patients. At 2 months, the OSDI score, TBUT, Schirmer I score, fluorescein staining score, impression cytology findings, and goblet cell count were significantly better in Group 1 than in Group 2 (P<.05). The interleukin‐1&bgr; and tumor necrosis factor‐&agr; concentrations were significantly less in the tears of Group 1 patients than in the tears of Group 2 patients, and catalase and superoxide dismutase 2 fluorescence intensities were significantly greater in the tears of Group 1 patients than in the tears of Group 2 patients (P<.05). Conclusions Preservative‐free sodium hyaluronate 0.1% and fluorometholone 0.1% eyedrops can improve the symptoms and signs of dry‐eye syndrome after cataract surgery. Preservative‐free fluorometholone eyedrops may have antiinflammatory and antioxidant effects in tears of patients with dry‐eye syndrome. Financial Disclosure No author has a financial or proprietary interest in any material or method mentioned.

Inverse Association between High Blood 25-Hydroxyvitamin D Levels and Diabetic Retinopathy in a Representative Korean Population

Purpose To investigate the association between 25-hydroxyvitamin D and diabetic retinopathy (DR). Methods A population-based cross-sectional study using a nation-wide, systemically stratified, multistage, clustered sampling method included a total of 18,363 subjects aged ≥40 years who participated in the Korean National Health and Nutrition Examination Survey during 2008–2012. All participants participated in standardized interviews, blood 25-hydroxyvitamin D level evaluations, and comprehensive ophthalmic examinations. Seven standard retinal fundus photographs were obtained from both eyes after pupil dilatation. DR was graded according to the modified Airlie House classification system. Results The blood 25-hydroxyvitamin D levels were 19.2 ng/mL in men and 17.9 ng/mL in women. After adjusting for potential confounders, including age, sex, diabetes duration, hemoglobin A1c levels, and hypertension, the odds ratios (OR) for any DR and proliferative DR among men decreased significantly in the highest blood 25-hydroxyvitamin D level quintile relative to the lowest quintile (OR, 0.37; 95% confidence interval [CI], 0.18–0.76; P for trend  = 0.004 and OR, 0.15; 95% CI, 0.03–0.83; P for trend  = 0.043). Conclusions This study provides the first epidemiologic findings of the inverse relationships of blood 25-hydroxyvitamin D levels with any DR and proliferative DR only in men. Considering anti-angiogenic and anti-fibrotic action of vitamin D, further studies including longitudinal and interventional analysis are warranted.

Prevalence and Risk Factors for Age-Related Macular Degeneration: Korean National Health and Nutrition Examination Survey 2008–2011

Abstract Purpose: To evaluate the prevalence of and risk factors for age-related macular degeneration (AMD) in a representative Korean population. Materials and Methods: A nationwide population-based cross-sectional study was conducted among the civilian, noninstitutionalized Korean population aged 40 and older (mean age, 55.7 years; 95% confidence interval [CI], 55.4–56.0). A total of 16,109 older (≥40 years of age) subjects participated in the Korean National Health and Nutrition Survey 2008–2011. All participants underwent standardized interviews and comprehensive ophthalmic examinations. Using physiologic mydriasis, a 45° digital fundus photograph was taken of both eyes of each participant. All fundus photographs were graded according to an international classification and grading system. Main outcome measures consisted of prevalence of early- and late-AMD. Results: Of the 16,109 subjects, fundus photographs were gradable for 14,352 (89.1%). The prevalence of early- and late-AMD in the Korean population was 6.0 and 0.6%, respectively. The prevalence of early-AMD increased from 1.5% in those aged 40–49 years to 16.2% in those aged ≥70 years. After adjusting for confounders, the prevalence of early-AMD increased with increasing age (odds ratio [OR], 1.08; CI, 1.06–1.09). For late-AMD, old age (OR, 1.09; CI, 1.04–1.14), male gender (OR, 2.45; CI, 1.11–5.37), high systolic blood pressure (OR, 1.03; CI, 1.00–1.06) and high fasting glucose level (OR, 0.97; CI, 0.94–0.99) were significant risk factors. Smoking was not associated with either early- or late-AMD in this Korean population. Conclusions: The present study provides the first population-based data on the prevalence of and risk factors for AMD in a representative Korean population. The prevalences of early- and late-AMD in this population were 6.0 and 0.6%, respectively. The prevalence of AMD in Koreans is higher than for those in other Asian countries and similar to that of Caucasians in Western countries.

A comparison of endothelial cell loss after phacoemulsification in penetrating keratoplasty patients and normal patients.

Purpose: To compare phacoemulsification-related endothelial cell loss in transplanted corneas and normal corneas. Methods: Forty-nine patients who underwent phacoemulsification/intraocular lens insertion after penetrating keratoplasty (PK-CAT group) (50 eyes) were compared with 65 patients who underwent phacoemulsification/intraocular lens insertion only (CAT group) (100 eyes). The PK-CAT group was divided into corneal endothelial dysfunction (CED) and opacity subgroups according to recipient endothelial function. Effective phacoemulsification time and endothelial density were analyzed. Results: The endothelial cell density after cataract surgery from 1 month (1772.72 ± 315.89) to 24 months (917.25 ± 372.75) in the PK-CAT group was significantly lower than that before cataract surgery (2189.36 ± 358.68) (P < 0.05) but that in CAT group was not significantly different from baseline during follow-up time (P < 0.05). The rate of graft survival in the opacity subgroup (82.0%) of the PK-CAT group was higher than that in the CED subgroup (54.5%) after 2 years (P < 0.05). The mean endothelial density in the opacity subgroup (1216.73 ± 271.63 cells/mm2) of the PK-CAT group was significantly higher than that in the CED subgroup (632.50 ± 238.29 cells/mm2) at 2 years after cataract surgery (P < 0.05). Conclusions: The phacoemulsification-related endothelial cell loss in transplanted corneas was higher than that in normal corneas. A possible factor contributing to higher endothelial cell loss in transplanted corneas is recipient endothelial dysfunction.