Shin Hae Park

The resistance patterns of normal ocular bacterial flora to 4 fluoroquinolone antibiotics.

Purposes: The purposes of this study were to determine the normal ocular bacterial flora isolated from patients undergoing anterior segment surgery and to evaluate their in vitro susceptibility to ciprofloxacin, levofloxacin, gatifloxacin, and moxifloxacin. Methods: During January 2006 to December 2006, conjunctival swabs taken from 385 eyes were inoculated onto 5% blood agar plates. The isolated bacteria were classified by analysis of 16s ribosomal DNA sequencing. Disk diffusion testing was performed in accordance with Clinical and Laboratory Standards Institute Performance Standards. Results: Three hundred sixty-three microorganisms were isolated in 291 samples from 385 eyes. Gram-positive species predominated (89.8%, 326 of the 363 isolates), and Staphylococcus epidermidis was the most frequently isolated organism, accounting for 60.6% (220 of the 363 isolates). For 293 gram-positive isolates, the prevalence rates of in vitro resistance to ciprofloxacin, levofloxacin, gatifloxacin, and moxifloxacin were 22.2% (65 isolates), 11.6% (34), 2.7% (8), and 5.1% (15), respectively. Two of the gram-negative isolates were resistant to only ciprofloxacin (5.4%, 2 of 37 isolates) and not to other fluoroquinolones. Of 62 ciprofloxacin-resistant, coagulase-negative staphylococci, 32 (51.6%) showed coresistance to levofloxacin. Seven organisms were resistant to all the fluoroquinolones. Conclusions: Fluoroquinolones have activity against normal aerobic flora of the ocular surface. Normal ocular flora, especially gram-positive species, has low resistance to the fourth-generation fluoroquinolones-gatifloxacin and moxifloxacin.

Measurement of Pupil Centroid Shift and Cyclotorsional Displacement Using Iris Registration

Background/Aims: To estimate the amount and nature of pupil centroid shift and cyclotorsion occurring between preoperative wavefront measurement and refractive surgery. Methods: This retrospective study comprised 183 eyes of 92 patients who had wavefront-guided LASIK using iris registration. We analyzed the pupil centroid shift and cyclotorsional displacement occurring between preoperative wavefront measurements and during the laser procedure. The eyes were measured by the WaveScan® Wavefront® system (VISX, Santa Clara, Calif., USA) and refractive surgery was performed with the VISX STAR S4 excimer laser system. Results: The mean magnitude of shifts in the location of pupil center was 0.26 ± 0.16 mm horizontally, 0.20 ± 0.16 mm vertically and 0.37 ± 0.13 mm vectorally. 162 eyes (88.5%) experienced more than 0.2 mm of shift. The mean amount of torsion was 2.58 ± 1.56° for 83 eyes showing incyclotorsion and 2.94 ± 1.87° for 100 eyes showing excyclotorsion. 117 eyes (63.9%) experienced more than 2° of cyclotorsion and 21 eyes (11.5%) experienced more than 5° of cyclotorsion. Conclusions: Pupil centroid shift and cyclotorsion occur in the majority of eyes undergoing laser treatment. The amount of pupil centroid shift and cyclotorsion shown in this study is considerable. Accurate compensation for cyclotorsion and pupil centroid shift may maximize the potential of visual quality of customized ablations.

A nationwide population-based study of low vision and blindness in South Korea.

PURPOSE To investigate the prevalence and associated risk factors of low vision and blindness in the Korean population. METHODS This cross-sectional, population-based study examined the ophthalmologic data of 22,135 Koreans aged ≥5 years from the fifth Korea National Health and Nutrition Examination Survey (KNHANES V, 2010-2012). According to the World Health Organization criteria, blindness was defined as visual acuity (VA) less than 20/400 in the better-seeing eye, and low vision as VA of 20/60 or worse but 20/400 or better in the better-seeing eye. The prevalence rates were calculated from either presenting VA (PVA) or best-corrected VA (BCVA). Multivariate regression analysis was conducted for adults aged ≥20 years. RESULTS The overall prevalence rates of PVA-defined low vision and blindness were 4.98% and 0.26%, respectively, and those of BCVA-defined low vision and blindness were 0.46% and 0.05%, respectively. Prevalence increased rapidly above the age of 70 years. For subjects aged ≥70 years, the population-weighted prevalence rates of low vision, based on PVA and BCVA, were 12.85% and 3.87%, respectively, and the corresponding rates of blindness were 0.49% and 0.42%, respectively. The presenting vision problems were significantly associated with age (younger adults or elderly subjects), female sex, low educational level, and lowest household income, whereas the best-corrected vision problems were associated with age ≥ 70 years, a low educational level, and rural residence. CONCLUSIONS This population-based study provides useful information for planning optimal public eye health care services in South Korea.

Absence of an association between lumican promoter variants and high myopia in the Korean population.

Purpose: To determine the association of single nucleotide polymorphisms (SNPs) in the promoter region of the lumican (LUM) gene with high myopic Korean patients. Methods: Genomic DNA samples were obtained from 128 unrelated Korean patients with high myopia who had refractive errors ≤ −9.25 and axial lengths ≥ 26.5 mm in both eyes, and 235 control subjects. We investigated two promoter SNPs of the LUM gene. Results: For the rs3759222, the C/C genotype was less prevalent in the high myopia group compared to the control group (46.1% vs. 53.2%); however, there was no statistical significance (p = 0.068, OR = 0.754, 95% CI: 0.491–1.159). The “C” allele frequency in the high myopia group (68.0%) was slightly lower than the control group (72.6%), but this difference was not statistically significant (p = 0.061, OR = 0.810, 95% CI:0.582–1.126). For the rs3759223, the genotype frequencies of T/T, T/C, and C/C were 67.2%, 26.6%, and 6.2%, respectively, in the high myopia group and 64.7%, 30.6%, and 4.7 %, respectively, in the control group. The allele frequency of T was 80.5% in the high myopia group and 80.0% in the control group (p = 0.077, OR = 1.03, 95% CI: 0.703–1.508). There were no significant differences in the distribution of genotype and allele frequencies for the two promoter SNPs tested. Conclusions: The current study did not support an association between the promoter SNPs of the LUM gene with high myopia in the Korean population.

Pathogenic mitochondrial DNA mutations and associated clinical features in Korean patients with Leber's hereditary optic neuropathy.

PURPOSE To identify the spectrum of pathogenic mitochondrial DNA (mtDNA) mutations and clinical features in Korean patients with genetically confirmed Lebers hereditary optic neuropathy (LHON). METHODS The medical records of 34 unrelated, genetically confirmed LHON patients were reviewed. Total genomic DNA was isolated from the peripheral blood leukocytes of the patients with suspected LHON, and primary or secondary mtDNA mutations were identified by direct sequencing. We analyzed the visual acuity (VA), color vision, RNFL thickness, and visual field (VF) at the final visit from 20 patients who were followed-up for more than 6 months after the onset of LHON. RESULTS Among 34 patients, 21 (61.8%) had the homoplasmic primary mutation, 11 (32.4%) had the homoplasmic secondary mutation, and 2 (5.9%) had the heteroplasmic primary mutation along with the homoplasmic secondary mutation. Analysis of mtDNA sequences revealed six different types of LHON-associated mutations: two primary LHON-associated primary mutations, m.11778G>A (20 patients, 58.8%) and m.14484T>C (3 patients, 8.8%), and four secondary LHON-associated mutations, which were m.3394T>C (3 patients, 8.8%), m.3497C>T (4 patients, 11.8%), m.11696G>A (4 patients, 11.8%), and m.14502T>C (2 patients, 5.9%). Secondary mutation-carrying patients demonstrated a decreased in RNFL thickness, similar to those in primary mutation-carrying LHON patients. These patients had a higher female ratio (P = 0.019), better VA (P = 0.043) and color vision (P = 0.005), as well as better VF. CONCLUSIONS In addition to common primary LHON-associated mutations, our study identified secondary mtDNA mutations, which should be considered when evaluating patients with optic atrophy.

Macular Ganglion Cell Analysis Determined by Cirrus HD Optical Coherence Tomography for Early Detecting Chiasmal Compression

Purpose To evaluate the performance of macular ganglion cell-inner plexiform layer (mGCIPL) measurement with Cirrus high-definition (HD) optical coherence tomography (OCT) for early detection of optic chiasmal compression. Methods Forty-six eyes of 46 patients with optic chiasmal compression caused by a pituitary adenoma (PA group), 31 eyes of 31 patients with normal tension glaucoma (NTG group), and 32 eyes of 32 normal participants (control group) were enrolled. The PA group was subdivided into two subgroups, which comprised patients with temporal visual field (VF) defects (perimetric PA group, 34 eyes) and without VF defect (preperimetric PA group, 12 eyes). The mGCIPL thickness and circumpapillary retinal nerve fiber layer (cpRNFL) thickness were measured using Cirrus HD-OCT. We calculated the number of patients who had an abnormal GCA sector map, defined as at least one yellow or red sector. Results Eyes in the perimetric PA group had significantly decreased mGCIPL thickness in all sectors. Eyes in the preperimetric PA group had significantly thinner mGCIPL in the superior, superonasal, inferonasal, and inferior sectors than eyes in control group, but no changes in cpRNFL parameters were observed. The mGCIPL thickness in inferonasal area showed the greatest AUC value (0.965), followed by the superonasal area (0.958) for discriminating preperimetric PA group from the control group. A higher reduction rate of mGCIPL thickness was noted in the nasal sector compared to other sectors, which was irrespective of temporal visual field defects. The mGCIPL thickness maps showed superonasal (P = 0.003) and inferonasal thinning in the PA group (P = 0.003), while inferotemporal thinning was revealed in the NTG group (P = 0.001). Conclusions Macular GCIPL thickness parameters obtained with the Cirrus HD-OCT were useful in early detection of chiasmal compression and differentiating from NTG by characteristic nasal mGCIPL thinning.

Heterozygous Avellino corneal dystrophy 9 years after photorefractive keratectomy: natural or laser-induced accelerated course?

Purpose: To report a photorefractive keratectomy (PRK)-treated patient who first developed stromal opacities with a typical granular pattern 9 years after surgery, which was confirmed as heterozygous Avellino dystrophy by DNA analysis. Methods: A 37-year-old woman, who had undergone PRK 17 years ago, has been followed for glaucoma and corneal dystrophy. She had preoperative clear corneas in both eyes. Results: Nine years after PRK, at the age of 29 years, 2-3 small, white, anterior stromal corneal opacities were first detected in both eyes. Seventeen years postoperatively, multiple anterior stromal corneal deposits with a dot, crumb, or snowflake appearance were noted to the same degree in both eyes. The intervening cornea was relatively clear. Her DNA was heterozygous for the R124H mutation. Conclusions: Slowly developing, mild corneal deposits occurred after PRK in this patient with heterozygote Avellino corneal dystrophy. Various clinical manifestations can occur after excimer laser refractive surgery in patients with Avellino corneal dystrophy.

Mutational spectrum of Korean patients with corneal dystrophy.

Corneal dystrophy typically refers to a group of rare hereditary disorders with a heterogeneous genetic background. A comprehensive molecular genetic analysis was performed to characterize the genetic spectrum of corneal dystrophies in Korean patients. Patients with various corneal dystrophies underwent thorough ophthalmic examination, histopathologic examination, and Sanger sequencing. A total of 120 probands were included, with a mean age of 50 years (SD = 18 years) and 70% were female. A total of 26 mutations in five genes (14 clearly pathogenic and 12 likely pathogenic) were identified in 49 probands (41%). Epithelial–stromal TGFBI dystrophies, macular corneal dystrophy and Schnyder corneal dystrophy (SCD) showed 100% mutation detection rates, while endothelial corneal dystrophies showed lower detection rates of 3%. Twenty six non‐duplicate mutations including eight novel mutations were identified and mutations associated with SCD were identified genetically for the first time in this population. This study provides a comprehensive characterization of the genetic aberrations in Korean patients and also highlights the diagnostic value of molecular genetic analysis in corneal dystrophies.

Retinopathy of prematurity in Korean infants with birthweight greater than 1500 g

Objective To determine the incidence and clinical features of, and risk factors for, retinopathy of prematurity (ROP) in Korean infants with birthweight (BW) >1500 g. Methods A total of 201 consecutive infants with BW >1500 g from January 2009 to December 2013 were included. The location and maximal stage of retinopathy observed were recorded for each infant. The associated systemic and maternal risk factors in infants with mild or absent ROP were compared with those in infants with treatment-requiring ROP. Results The total incidence of ROP was 11.94% and that of treatment-requiring ROP was 3.98%. Two patients with gestational age (GA) >32 weeks and BW >1500 g had treatment-requiring ROP. 15 eyes from eight infants with type I ROP required laser photocoagulation. The mean BWs and GAs in the treatment-requiring ROP group were significantly lower than those in the no or mild ROP group. Total duration of oxygen supplementation, surfactant usage, respiratory distress syndrome, bronchopulmonary dysplasia, antibiotic use for more than 14 days and the number of ROP-associated risk factors significantly increased the likelihood of treatment-requiring ROP (p=0.002, p=0.008, p=0.008, p=0.000, p=0.015, and p=0.004, respectively). Conclusion Our study confirmed that treatment-requiring ROP does occur in infants with BW >1500 g. To avoid overlooking infants with vision-threatening ROP, an evaluation of the data from larger BW preterm infants is advisable so that screening guidelines in neonatal care units may be refined.

Refractive outcomes of phacoemulsification and intraocular lens implantation after pars plana vitrectomy.

Purpose: To describe the visual acuity outcomes of patients undergoing phacoemulsification and intraocular lens implantation after pars plana vitrectomy, and to compare of refractive errors after phacoemulsification and intraocular lens implantation in the cases of vitrectomized eyes and nonvitrectomized eyes. Methods: The subjects of this study were 45 eyes performed phacoemulsification after vitrectomy from January 2004 to February 2007. Office records were reviewed for best-corrected visual acuity before and after phacoemulsification. In 45 vitrectomized eyes (Group V) and 50 nonvitrectomized eyes (Group P), we compared the predicted refraction by preoperative data, and actual postoperative refraction of postoperative 2 months. Results: The average interval from pars plana vitrectomy to phacoemulsification was 11.5 months. In Group V, 41 of 45 eyes (91.1%) had improved best-corrected visual acuity more than one line, after phacoemulsification. Although, more hyperopic shift was noted in Group V than Group P, there was no significant difference between the predicted refraction by preoperative data and postoperative manifest refraction in both groups. Conclusion: Phacoemulsification after pars plana vitrectomy showed no significant difference between the predicted refraction by preoperative data and the actual postoperative refraction.