Hee Seung Chin

Association between Complement Factor H Gene Polymorphisms and Neovascular Age-Related Macular Degeneration in Koreans

PURPOSE This study was undertaken to investigate the association between the complement factor H (CFH) gene and exudative age-related macular degeneration (AMD) in Korean patients. METHODS Genomic DNA was isolated from the peripheral leukocytes of patients with exudative AMD (n = 114) and control subjects (n = 187). The sole criterion for exudative AMD was the presence of choroidal neovascularization. Four single-nucleotide polymorphisms (SNPs: -275C>T, I62V, Y402H, and IVS15) located in promoter, exon 2, exon 9, and intron 15 of the CFH gene were genotyped by PCR-based direct sequencing. RESULTS The frequency of the C allele of Y402H (AMD, 10.5%; control, 6.5%) was found to be lower in Koreans than in Caucasians. In the present study, the difference between the frequencies of Y402H in cases and control subjects did not reach statistical significance (P = 0.071). However, the frequencies of the major alleles of three SNPs (-275C>T, I62V, and IVS15) were significantly different in patients and control subjects, and these SNPs were found to be separately associated with an elevated risk of exudative AMD. Seven haplotypes were identified in Koreans. Haplotype analysis showed that two haplotypes (TGTG, CGTG) conferred significantly higher risks of exudative AMD (P = 0.013, 0.035), and one haplotype (CATA) was significantly protective (P < 0.001). CONCLUSIONS In Korean subjects, CFH polymorphism appears to be a considerable hereditary contributor to exudative AMD. Y402H polymorphism which has been suggested to be a major risk factor of AMD in Caucasians was found to be only marginally associated with exudative AMD with low frequency, whereas three adjacent SNPs in the CFH gene were significantly associated with AMD in Koreans.

Optical coherence tomographic patterns in diabetic macular oedema: prediction of visual outcome after focal laser photocoagulation

Aim: To identify optical coherence tomography (OCT) patterns predictive of visual outcome in diabetic macular oedema (DMO) patients who undergo focal laser photocoagulation. Methods: This study involved 70 eyes (45 patients) with clinically significant macular oedema that underwent focal laser photocoagulation using the Early Treatment Diabetic Retinopathy Study protocol. Preoperative macular OCT images were retrospectively examined. OCT features were classified into four patterns: diffuse retinal thickening (DRT); cystoid macular oedema (CMO), serous retinal detachment and vitreomacular interface abnormalities (VMIA). Changes in retinal thickness, retinal volume and visual acuity (VA) after focal laser photocoagulation were evaluated and compared with respect to their OCT features. Results: After focal laser photocoagulation, changes in retinal thickness and retinal volume were significantly different for different OCT types (p = 0.002 and p<0.001). The change in VA from baseline was not significantly different between groups (p = 0.613). The DRT pattern was associated with a greater reduction in retinal thickening and better VA improvement than the CMO or VMIA patterns. Proportions of patients with persistent DMO (central macular thickness >250 μm after laser treatment) were greater for the CMO and VMIA patterns than DRT pattern. Conclusion: DRT patients achieved a greater reduction in retinal thickening and greater VA increases than CMO and VMIA patients. We suggest that classifying DMO structural patterns using OCT might allow visual outcome to be predicted after laser photocoagulation.

Changes in subfoveal choroidal thickness and choroidal extravascular density by spectral domain optical coherence tomography after haemodialysis: a pilot study

Aims To examine the changes in the subfoveal choroidal thickness (SFCT) and choroidal density using spectral domain optical coherence tomography (SD-OCT) before and after haemodialysis (HD). Methods 28 eyes of 19 patients with chronic renal failure (CRF) undergoing HD were included. Ophthalmologic examinations including SD-OCT were performed 1 h before and after HD. The SFCT was measured manually using Image J software, and the relationships between the change in SFCT and in the systemic parameters after HD were evaluated. The changes in choroidal extravascular density of the OCT image after HD were evaluated by comparing brightness value obtained with Adobe Photoshop software. Results The mean SFCT of all eyes increased significantly from 276.94±58.73 µm to 288.29±65.57 µm (p=0.003). In the univariate generalised estimating equation (GEE), the SFCT increased significantly after HD (p=0.006). After adjusting for age, gender and other significant factors in univariate analysis, the SFCT increased significantly after HD (p=0.032). The decrease in systolic blood pressure (SBP) was associated with the increase in SFCT (p=0.013). The choroidal extravascular density of OCT image increased after HD (p<0.001) and the mean change was 12.35±9.72. Conclusions In the SD-OCT image, the SFCT became thicker and the choroidal extravascular density increased after HD in patients with CRF. The decrease in SBP after HD was associated with an increase in SFCT. The choroidal autoregulatory control of ocular hemodynamic change and shifting of fluid and molecules between the blood and choroidal interstitium might be involved in the mechanism of these choroidal changes.

Progression of Impending Central Retinal Vein Occlusion to the Ischemic Variant Following Intravitreal Bevacizumab

A 60-year-old woman who had experienced two episodes of amaurosis fugax in her right eye presented with vision loss. Two weeks earlier, at a private clinic, she was diagnosed with impending central retinal vein occlusion (CRVO) of the right eye and received an intravitreal injection of bevacizumab. Two weeks after this injection she was diagnosed with ischemic CRVO. At 11-weeks post-presentation, extremely ischemic features were observed with fluorescein angiographic findings of severe vascular attenuation and extensive retinal capillary obliteration. At 22-weeks post-presentation she was diagnosed with neovascular glaucoma; she experienced no visual improvement over the following several months.

Glaucoma diagnostic value of the total macular thickness and ganglion cell-inner plexiform layer thickness according to optic disc area

Aims This study examined the diagnostic value of the perimacular ganglion cell-inner plexiform layer (GCIPL) thickness in the detection of glaucoma according to the optic disc area. Methods The participants underwent reliable standard automated perimetry tests and Cirrus optical coherence tomography. The area under the receiver operating characteristic curve (AUC) was used to determine the diagnostic ability of the GCIPL, total macular thickness, retinal nerve fibre layer (RNFL) and optic nerve head parameters. Subsequently, optic disc areas of ≤1.9, ≤2.4 and >2.4 mm2 were chosen arbitrarily, and the AUCs and sensitivities at fixed specificities were compared for each. Results 87 normal subjects and 96 glaucoma patients were enrolled. The mean GCIPL thickness and RNFL showed similar ability to diagnose glaucoma (p=0.911). The mean GCIPL thickness had higher diagnostic ability than the central retinal subfield thickness (p=0.001), comparable with that of the retinal cube volume (p=0.840) and mean retinal cube thickness (p=0.840). The mean RNFL (0.866), the minimum GCIPL (0.840) and the inferior and inferotemporal (0.853) disc had the highest AUCs for small, medium and large discs, respectively. Conclusions The macular GCIPL thickness, total macular cube thickness, circumpapillary RNFL thickness and disc rim area showed similar performance in diagnosing glaucoma, irrespective of the optic disc size.

Intravitreal Triamcinolone Acetonide Injection at the Time of Pars Plana Vitrectomy for Retained Lens Material

PURPOSE To report the experiences at our institute of pars plana vitrectomy (PPV) in combination with intravitreal triamcinolone acetonide (IVTA) injection in patients with retained lens material after cataract surgery. METHODS The medical records of patients who underwent PPV between January 2005 and December 2006 after complicated cataract surgery in which lens material was dropped into the vitreous cavity were reviewed retrospectively. RESULTS Five eyes of five patients were treated by vitrectomy and removal of the dislocated lens material and were administered an adjuvant intravitreal injection of 4 mg triamcinolone acetonide at the end of surgery. IVTA administration induced a rapid improvement in vision within six weeks postoperatively. Final visual acuity was 20/32 or better in all patients. Inflammatory cystoid macular edema (CME) that existed preoperatively was promptly improved after IVTA. Intraocular pressure increased transiently in one patient. No procedure-related complications were observed. CONCLUSIONS PPV with additional IVTA was successfully performed in five eyes with retained lens material and resulted in a marked resolution of vitreous inflammation, an improvement in CME and rapid visual recovery. The authors recommend that IVTA administration should be investigated more thoroughly as an adjunct during the management of retained lens material.

Guideline Development for the Evaluation of Visual Impairment in Korea

This guideline is developed to provide criteria for evaluating permanent impairment of the visual system as it affects an individuals ability to perform activities of daily living. This new assessment system is based on the 5th and 6th edition of American Medical Association and McBride impairment assessment system but revised on the consideration of Korean culture and simple application. This evaluation of impairment is based on an assessment of visual acuity and visual field. Especially it weighs binocular vision and binocular visual fields and the binocular vision and binocular visual fields provide 50% of weight and the right and left eye each contribute 25%. A further adjustment of the impairment rating is included at the final step of this evaluation. Functional deficits for individual adjustments include diplopia, problem of accommodation, abnormality of eyelids, tearing, cosmetic problems from cornea opacity, glare, aphakia, and dark-adaptation. The adjustment can be added to impairment rating up to 15%. Further study is necessary to revise and update of this disability evaluation that have potential problems in actual application.

Effects of Vitreomacular Traction on Ranibizumab Treatment Response in Eyes with Neovascular Age-related Macular Degeneration

Purpose To investigate the effects of vitreomacular traction (VMT) on ranibizumab treatment response for neovascular age-related macular degeneration (AMD). Methods A retrospective review of 85 eyes of 85 patients newly diagnosed with neovascular AMD was conducted. Patients were eligible if they had received more than three consecutive monthly ranibizumab (0.50 mg) treatments and ophthalmic evaluations. Patients were classified into a VMT (+) group or VMT (-) group according to optical coherence tomography imaging. Best corrected visual acuity and central retinal thickness (CRT) measurements were obtained at three and six months after initial injection. Results One month after the third injection, mean visual acuity (VA) increases of 6.36 and 9.87 letters were observed in the VMT (+) and VMT (-) groups, respectively. The corresponding mean CRT values decreased by 70.29 µm and 121.68 µm, respectively. A total 41 eyes were identified as eligible for a subsequent fourth injection; 71.1% of patients (27 eyes) in the VMT (+) group but only 29.8% of patients in the VMT (-) group needed a subsequent fourth injection. Follow-up was extended to six months for 42 of the 85 enrolled patients (49.4%). The trends in VA and optical coherence tomography were found to be maintained at six-month follow-up. Conclusions VA and CRT appeared to be more improved after ranibizumab treatment in the VMT (-) group compared to the VMT (+) group. VMT might antagonize the effect of ranibizumab treatment in a subpopulation of AMD patients.

Effects of Histone Deacetylase Inhibitor (Valproic Acid) on the Expression of Hypoxia-inducible Factor-1 Alpha in Human Retinal Müller Cells

Purpose To evaluate the effects of valproic acid (VPA), a histone deacetylase inhibitor (HDACI), on the expression of hypoxia-inducible factor-1 alpha (HIF-1α) and vascular endothelial growth factor (VEGF) in human retinal Müller cells under hypoxic conditions. Methods Chemical hypoxia was induced in human retinal Müller cells (MIO-M1) by treatment with increasing concentrations of cobalt(II) chloride (CoCl2). Müller cells were also treated with a set concentration of CoCl2, along with various concentrations of VPA. The expression of HIF-1α and VEGF in the treated Müller cells was determined by enzyme-linked immunosorbent assay. Results Exposure of human retinal Müller cells to increasing concentrations of CoCl2 produced a dose-dependent increase in HIF-1α expression. The addition of increasing concentrations of VPA lead to a dose-dependent decrease in expression of HIF-1α and VEGF in Müller cells exposed to a set concentration of CoCl2. Conclusions HDACI VPA downregulated the expressions of HIF-1α and VEGF in human retinal Müller cells under hypoxic conditions. Using HDACI to target HIF-1α expression in Müller cells could be a new therapeutic strategy for the treatment of retinal vascular diseases.

Comparison of Repeatability and Agreement between Swept-Source Optical Biometry and Dual-Scheimpflug Topography

Purpose To assess the repeatability and agreement of parameters obtained with two biometers and to compare the predictability. Methods Biometry was performed on 101 eyes with cataract using the IOLMaster 700 and the Galilei G6. Three measurements were obtained per eye with each device, and repeatability was evaluated. The axial length (AL), anterior chamber depth (ACD), keratometry (K), white-to-white (WTW) corneal diameter, central corneal thickness (CCT), and lens thickness (LT) were measured and postoperative predictability was compared. Results Measurements could not be obtained with the IOLMaster 700 in one eye and in seven eyes with the Galilei G6 due to dense cataract. Both the IOLMaster 700 and Galilei G6 showed good repeatability, although the IOLMaster 700 showed better repeatability than the Galilei G6. There were no statistically significant differences in AL, ACD, steepest K, WTW, and LT (P > 0.050), although flattest K, mean K, and CCT differed (P < 0.050). The proportion of eyes with an absolute prediction error within 0.5 D was 85.0% for the IOLMaster 700 and was 80.0% for the Galilei G6 based on the SRK/T formula. Conclusions Two biometers showed high repeatability and relatively good agreements. The swept-source optical biometer demonstrated better repeatability, penetration, and an overall lower prediction error.