Hyeong Gon Yu

Comparison of efficacy and safety between half-fluence and full-fluence photodynamic therapy for chronic central serous chorioretinopathy.

Purpose: To compare the efficacy and safety of half-fluence photodynamic therapy (PDT) and conventional PDT in chronic central serous chorioretinopathy. Methods: A multicenter retrospective comparison study. Retrospective review of 60 patients including 29 patients (34 eyes) who received half-fluence PDT and 31 patients (33 eyes) who received conventional PDT for the treatment of chronic central serous chorioretinopathy. Best-corrected visual acuity, central fovea retinal thickness and resolution of subretinal fluid on optical coherence tomography, and choroidal perfusion decrease on indocyanine green angiography were assessed. Choriocapillaris perfusion decrease was quantified as mean gray value ratio of treated and nontreated areas using commercial imaging software. Results: Treatment success without recurrence was achieved in 32 of 34 eyes (94.1%) treated with half-fluence PDT and 33 of 33 eyes (100%) treated with conventional PDT (P = 0.493). There was no difference in final best-corrected visual acuity (logarithm of the minimal angle of resolution) between the 2 groups (0.17 ± 0.32 vs. 0.21 ± 0.39; P = 0.603). Choriocapillaris perfusion decrease quantified from post-PDT indocyanine green angiography was significantly more severe in the conventional PDT group (P = 0.006), and it showed a positive correlation with retinal thinning after PDT (R2 = 0.380; P < 0.001). Conclusion: Half-fluence PDT is as effective as conventional PDT, while minimizing the deleterious effect on choriocapillaris perfusion and retinal thickness.

CD8brightCD56+ T Cells Are Cytotoxic Effectors in Patients with Active Behçet’s Uveitis

Behçet’s uveitis, characterized by chronic recurrent uveitis and obliterating retinal vasculitis, frequently causes bilateral blindness. Intraocular infiltration of TCRαβ+CD8brightCD56+ cells was a distinct feature in Behçet’s uveitis. However, phenotypic natures and effector functions of the cells have remained elusive. This study was conducted to determine phenotypic and functional characteristics and cytotoxic mechanisms of CD8brightCD56+ T cells in Behçet’s uveitis. CD11b+CD27−CD62L− phenotypes of CD8brightCD56+ T cells were increased in patients with active Behçet’s uveitis compared with inactive Behcet’s patients and normal controls. Interestingly, CD45RAdimCD45RO− phenotypes were expanded, and CD94 expression was markedly up-regulated in contrast to the down-regulation of NKG2D. Furthermore, these subsets were polarized to produce IFN-γ and contained high amounts of preformed intracellular perforin while exclusively expressing surface FasL upon PI stimulation. Moreover, the cytolytic functions of freshly isolated CD8brightCD56+ T cells were up-regulated against both K562 (NK-sensitive) and Raji (NK-resistant) cells, which were effectively inhibited by perforin inhibitor (concanamycin A). Their cytolytic activity against HUVECs was also increased and was effectively suppressed by Fas ligand inhibitor (brefeldin A) and partly by perforin inhibitor. Furthermore, cytolytic functions of PMA and ionomycin-stimulated CD8brightCD56+ T cells against HUVECs were greatly enhanced, by pretreatment of recombinant human IFN-γ on HUVECs. Therefore, CD8brightCD56+ T cells in Behçet’s uveitis are characterized by cytotoxic effector phenotypes with functional NK receptors and function as strong cytotoxic effectors through both Fas ligand-dependent and perforin-dependent pathways.

Myopic choroidal neovascularisation: current concepts and update on clinical management

Choroidal neovascularisation (CNV) is a common vision-threatening complication of myopia and pathological myopia. Despite significant advances in understanding the epidemiology, pathogenesis and natural history of myopic CNV, there is no standard definition of myopic CNV and its relationship to axial length and other myopic degenerative changes. Several treatments are available to ophthalmologists, but with the advent of new therapies there is a need for further consensus and clinical management recommendations. Verteporfin photodynamic therapy has been an established treatment for subfoveal myopic CNV for many years, but this treatment does not restore visual acuity and is associated with long-term chorioretinal atrophy. More recently, clinical trials investigating the efficacy and safety of anti-vascular endothelial growth factor agents in patients with myopic CNV have demonstrated substantial visual acuity gains and quality of life increases compared with photodynamic therapy. These enhanced outcomes provide updated evidence-based clinical management guidelines of myopic CNV, and increase the need for a generally accepted definition for myopic CNV. This review critically summarises the latest myopic CNV literature in the context of clinical experience and recommends a myopic CNV treatment algorithm.

The number of CD8+ T cells and NKT cells increases in the aqueous humor of patients with Behçet's uveitis

To determine whether there are differences in the immunopathogenesis of different endogenous uveitis syndromes, the phenotypic characteristics of immune cells were analysed among patients with endogenous uveitis. The aetiology of the uveitis included idiopathic recurrent acute anterior uveitis (18 patients), idiopathic intermediate uveitis (13 patients), Behçets uveitis (17 patients), Vogt–Koyanagi–Harada syndrome (7 patients), and so on. Flow cytometric analysis was performed using immune cells of the aqueous humor and the peripheral blood during the active phase of intraocular inflammation, and monoclonal antibodies to CD3, CD4, CD8, CD14, CD19, CD56, TCR γδ, pan TCR αβ and Vα24. CD8+ T cells were predominant in the aqueous humor of the patients with Behçets uveitis, whereas CD4+ T cells were mainly found in the aqueous humor of patients other than those with Behçets uveitis. The number of NKT (CD3+CD56+) cells was significantly higher both in the aqueous humor and the peripheral blood of the patients with Behçets uveitis compared with the other groups (P < 0·05). CD8+CD56+ cells were the predominant subtype of the increased NKT cells in patients with Behçets uveitis. In addition, intraocular infiltration of CD14+ cells significantly differed among the uveitis patients (P < 0·05). These results suggest that the immunopathogenesis of endogenous uveitis can vary between syndromes, and that CD8+CD56+ NKT cells may play an important role in the immunopathogenesis of Behçets uveitis.

Age-Related Macular Degeneration in a Screened South Korean Population: Prevalence, Risk Factors, and Subtypes

PURPOSE To identify the prevalence, risk factors, and subtypes of age-related macular degeneration (AMD) in a screened South Korean population. METHODS A total of 10,890 participants (aged 50-92) who underwent a health check-up at Kangbuk Samsung Hospital from January to December 2006 were included. Fundus photographs and systemic risk factors were assessed. Subtype frequencies of neovascular AMD were recorded according to angiograms. AMD was defined in accord with the international classification and grading system. Logistic regression analyses were performed to identify risk factors for AMD. RESULTS The mean age of the 10,890 participants was 57.2 +/- 6.3 years (50-92 years), and 56.2% were men. The age-gender-adjusted prevalence of early AMD was 5.07%. Multiple logistic regression analysis showed that age (OR per 10-year increment, 2.22) and high blood pressure (adjusted OR: 1.35) were independent risk factors for early AMD. The age-gender-adjusted prevalence of late AMD was 0.34%. Only age was significantly associated with late AMD. Of 9 exudative AMD patients who received fluorescein angiography or indocyanine green angiography, 6 eyes (66.7%) showed choroidal neovascularization, 2 eyes (22.2%) had polypoidal choroidal vasculopathy (PCV), and 1 eye (11.1%) had retinal angiomatous proliferation. CONCLUSION In this study, the prevalence of early AMD was similar to other studies though the prevalence of late AMD was low. High blood pressure as well as age was a risk factor of early AMD. South Koreans may have a higher prevalence of PCV than white populations. These findings provide preliminary information for further investigation of AMD in South Koreans.

Depression and the vision-related quality of life in patients with retinitis pigmentosa

Aims: To assess the relationship between depression and the vision-related quality of life in patients with retinitis pigmentosa (RP). Methods: The study included 144 patients diagnosed as having RP. The mean age of the patients was 38.5 (SD 13.3) years, and 42% of the subjects were women. They answered the National Eye Institute Visual Function Questionnaire (NEI-VFQ) to assess the vision-related quality of life and the Beck Depression Inventory (BDI) to assess depressive symptoms. Patients were classified into groups with and without depression according to the BDI score. The NEI-VFQ composite and subscale scores were compared between groups. The correlations between the BDI and the NEI-VFQ, weighted visual acuity (WVA) and functional vision score (FVS) were investigated. Results: The depressed group had significantly less subjective visual function compared with the non-depressed group. A negative correlation was observed between the BDI and the NEI-VFQ scores, while no correlation was found between the BDI score and WVA or FVS. Conclusion: The RP patients with depression had poorer vision-related functions compared with those patients without depression, which cannot be explained by the visual acuity. Interventions to diagnose and treat depression are necessary to enhance the overall quality of life in RP patients.

Factors influencing refractive outcomes after combined phacoemulsification and pars plana vitrectomy: results of a prospective study.

PURPOSE: To evaluate the factors influencing the refractive outcomes of combined phacoemulsification, foldable intraocular lens (IOL) implantation, and pars plana vitrectomy (PPV). SETTING: Department of Ophthalmology, Seoul National University Hospital, Seoul, Korea. METHODS: One hundred fifty‐four consecutive patients who had combined phacoemulsification, IOL implantation, and PPV between September 2001 and August 2004 were enrolled in a prospective study. Refractive, keratometric, and axial length measurements were performed preoperatively and 4 months postoperatively. The factors influencing the postoperative refractive outcomes were analyzed. RESULTS: The mean refractive prediction error (ie, actual minus predicted spherical equivalent [SE]) was −0.06 diopters (D) ± 0.75 (SD). In long eyes (preoperative axial length more than 24.5 mm), the mean predicted SE and actual SE were −0.81 ± 0.76 D and −1.24 ± 0.79 D, respectively; the difference was significantly different (P = .001, paired t test). Patients with a preoperative visual acuity worse than 5/200 and those with preoperative foveal detachment had a significant postoperative myopic shift (P = 0.024 and P = 0.002, respectively; paired t test). Postoperative refractive error was not influenced by the intraocular air or gas tamponade during surgery (P = 0.336, paired t test). CONCLUSIONS: The combined surgery included a small biometric error that was within the tolerable range in most cases. However, myopic shifts developed in patients with long axial lengths, poor preoperative visual acuity, and the preoperative presence of foveal detachment.

Verification of biomarkers for diabetic retinopathy by multiple reaction monitoring.

Multiple reaction monitoring was used to verify target proteins in 3 groups of vitreous and plasma samples from 3 stages of diabetic retinopathy: macular hole (nondiabetic control), nonproliferative diabetic retinopathy, and proliferative diabetic retinopathy. Twelve target proteins were quantified using triple quadrupole LC-MS/MS and 3 methods to determine the transitions (information-dependent analysis, the MIDAS workflow, and the PeptideAtlas database). This study might be the first MRM experiment to analyze large numbers of clinical vitreous and plasma samples for biomarker verification. Consequently, several biomarker candidates were identified for use in further applications.

What is the evidence of a role for host genetics in susceptibility to influenza A/H5N1?

The apparent family clustering of avian influenza A/H5N1 has led several groups to postulate the existence of a host genetic influence on susceptibility to A/H5N1, yet the role of host factors on the risk of A/H5N1 disease has received remarkably little attention compared to the efforts focused on viral factors. We examined the epidemiological patterns of human A/H5N1 cases, their possible explanations, and the plausibility of a host genetic effect on susceptibility to A/H5N1 infection. The preponderance of familial clustering of cases and the relative lack of non-familial clusters, the occurrence of related cases separated by time and place, and the paucity of cases in some highly exposed groups such as poultry cullers, are consistent with a host genetic effect. Animal models support the biological plausibility of genetic susceptibility to A/H5N1. Although the evidence is circumstantial, host genetic factors are a parsimonious explanation for the unusual epidemiology of human A/H5N1 cases and warrant further investigation.

Increased choroidal neovascularization following laser induction in mice lacking lysyl oxidase-like 1.

PURPOSE Age-related degradation of the elastic lamina in Bruchs membrane may have a permissive effect on the growth of choroidal neovascularization (CNV). This study investigated the influence of defective elastic fiber maintenance in the development of laser-induced CNV. METHODS A mouse lacking lysyl oxidase-like (LOXL)-1, an enzyme essential for elastin polymerization, was studied. The morphologic characteristics of the elastic lamina within Bruchs membrane were examined in mutant and wild-type (WT) eyes. Laser-induced CNV was evaluated by fluorescein angiography and choroidal flat mounts. Immunohistochemistry for elastin was performed on the CNV lesions, and vascular endothelial growth factor (VEGF) levels were determined by ELISA. Soluble elastin and matrix metalloproteinase (MMPs) levels were also analyzed by immunoblotting. RESULTS The elastic lamina of Bruchs membrane in the LOXL1-deficient mice was fragmented and less continuous than in the WT controls. The mutant mice showed increased levels of soluble elastin peptides and reduced elastin polymer deposition in neovascular membranes. Significantly larger CNV with greater leakage on fluorescein angiography developed in mutant mice. VEGF levels in the RPE/choroid were higher in the knockout mice on days 7 and 14 after laser (P < 0.05). MT1-MMP (MMP14) was also elevated after laser in the LOXL1 mutant eyes compared to the WT controls. CONCLUSIONS These results show that a systemic defect in elastic fiber deposition affects Bruchs membrane integrity and leads to more aggressive CNV growth. The latter may be partially mediated by abnormal signaling from the accumulation of soluble elastin peptides.