Suk Ho Byeon

Incidence and clinical patterns of polypoidal choroidal vasculopathy in Korean patients.

PurposeTo determine the incidence, demographic features, and clinical characteristics of polypoidal choroidal vasculopathy (PCV) in Korean patients.MethodsA retrospective review was undertaken of 392 eyes of 321 symptomatic patients suspected of having exudative age-related macular degeneration (AMD) after their first visit to a tertiary hospital between February 2002 and May 2006. All patients underwent a complete ophthalmic examination, including fluorescein and indocyanine green angiography (ICGA).ResultsOf the 321 patients (392 eyes), 79 (98 eyes, 24.6%) were diagnosed with PCV. The mean PCV patient age was 64.6 ± 7.6 years. PCV was more common in men (78.5%), and was usually unilateral (75.9%). In terms of PCV clinical manifestation, 52% of patients showed an exudative pattern, 34.7%, a hemorrhagic pattern, and 13.3%, an extensive hemorrhagic pattern. The mean visual acuity at presentation was 0.231 ± 0.256. Classification was based on ICGA findings; 52% of patients showed relatively large aneurismal dilations, 25.5% showed atypical vessel deformations, and 22.5% showed dense clusters of numerous small hyperfluorescent dots.ConclusionsThe incidence of PCV in Korean exudative AMD patients was relatively high compared with that in other ethnic groups. As in other Asian patient populations, PCV occurred more commonly in men and was predominantly unilateral.

Problems Associated with the 25-Gauge Transconjunctival Sutureless Vitrectomy System during and after Surgery

Objective: To report the initial experiences with the 25-gauge transconjunctival sutureless vitrectomy (TSV) system, including intraoperative and postoperative problems. Methods: We retrospectively reviewed the medical records and surgical videotapes of 50 consecutive patients who underwent vitrectomy performed by one surgeon using the TSV system. Results: Intraoperatively, we encountered such problems as difficulty in inserting the microcannula, which led to deformity, instability of the microcannula, self-disconnection of the infusion tip and resultant lens damage, and conversion to 20-gauge conventional vitrectomy. Postoperatively, there were 8 cases with hypotony (IOP < 6 mm Hg) on day 1, 6 cases with elevated IOP, and 3 cases with retinal detachment during follow-up. Conclusion: Though certain problems exist during and after surgeries using TSV, this system is both convenient and safe for various vitreoretinal procedures.

Vascular Endothelial Growth Factor as an Autocrine Survival Factor for Retinal Pigment Epithelial Cells under Oxidative Stress via the VEGF-R2/PI3K/Akt

PURPOSE Vascular endothelial cell growth factor (VEGF) is strongly induced by oxidative stress in retinal pigment epithelial (RPE) cells, and VEGF-A is a survival factor for various cell types. This study was conducted to determine whether the autocrine VEGF signaling pathway in RPE cells is involved in the mechanism of adaptive response to oxidative stress. METHODS ARPE-19 cells were treated with hydrogen peroxide, and cell death was measured by flow cytometry with annexin V-fluorescein isothiocyanate. Survival analysis was performed with pretreatment of VEGF-A-neutralizing antibodies, VEGF receptor tyrosine kinase inhibitor (SU5416), or VEGF-A receptor-neutralizing antibodies (anti-VEGF-R1 and anti-VEGF-R2). The expression of VEGF-A, -R1, -R2, and soluble VEGF-R1 was determined by semiquantitative RT-PCR or Western blot analysis. Phosphorylation of VEGF-R2 was detected with immunoprecipitation and immunoblot analysis. RESULTS Hydrogen peroxide-induced cell death was promoted by pretreatment with VEGF-A and anti-VEGF-R2-neutralizing antibodies, but not with anti-VEGF-R1-neutralizing antibody. Phosphorylation of VEGF-R2 in RPE cells was induced by hydrogen peroxide, and pretreatment with anti-VEGF-A-neutralizing antibody inhibited phosphorylation. Phosphorylation of Akt under oxidative stress was abrogated by pretreatment with neutralizing antibodies against either VEGF-A or SU5416. CONCLUSIONS Autocrine VEGF-A enhanced RPE cell survival under oxidative stress; the autocrine VEGF-A/VEGF-R2/PI3K/Akt pathway is involved. Neutralization of VEGF-A signaling, as in eyes with age-related macular degeneration, may influence RPE cell survival.

NFAT5 Induction and Its Role in Hyperosmolar Stressed Human Limbal Epithelial Cells

PURPOSE To introduce a tonicity response gene regulator, NFAT (nuclear factor of activated T-cell)-5 and determine its expression mechanism and specific roles in human limbal epithelial cell (HLECs) subjected to hyperosmolar stress. METHODS NFAT5 expression was determined in various hyperosmolar conditions in HLECs by RT-PCR and Western immunoblot analyses. NFAT5 translocation during hyperosmolar stress was observed by immunocytochemistry. NFAT5-related signal transduction activity was measured on the basis of inhibition of NF-kappaB (nuclear factor-kappaB), and MAPK activity. TNF-alpha and IL-1beta, -6, and -8 levels were determined after inhibition of NFAT5 and/or NF-kappaB. Hyperosmotic apoptotic cell death, with or without inhibition of NFAT5, was measured by flow cytometry. RESULTS NFAT5 was induced and translocated to the nucleus under conditions of hyperosmolar stress. It was inhibited by SB239063, a p38 MAPK inhibitor. Among the inflammatory cytokines induced in hyperosmolar stress conditions, IL-1beta and TNF-alpha levels were significantly reduced after inhibition of NFAT5. Of interest, even after 48 hours of hyperosmolar stress, 45% of HLECs survived. HLEC apoptosis increased markedly as a result of NFAT5 suppression. Moreover, most of the HLECs underwent cell death on dual inhibition of NF-kappaB and NFAT5. CONCLUSIONS NFAT5 is induced and translocates to the nucleus in HLECs undergoing hyperosmolar stress through activation of p38. IL-1 beta and TNF-alpha are induced via NFAT5 activation. Our data collectively indicate that NFAT5 may be an important gene regulator and survival factor in hyperosmolar stressed HLECs.

Foveal ganglion cell layer damage in ischemic diabetic maculopathy: correlation of optical coherence tomographic and anatomic changes.

PURPOSE To describe the morphologic features of ischemic diabetic maculopathy by high-resolution optical coherence tomography (OCT) and their correlation with the damaged foveal avascular zone (FAZ) on fluorescein angiography (FA). DESIGN Observational case series. PARTICIPANTS One hundred twenty-four eyes of 63 patients with diabetic retinopathy and acceptable FA and OCT images were studied. Twenty-three normal fellow eyes of 23 nondiabetic patients with unilateral acute central serous choroidopathy also were studied. METHODS High-speed Fourier-domain OCT was used with a speckle noise-reduction technique to obtain detailed horizontal and vertical images through the center of the fovea and horizontal raster scans every 100 microm. Foveal ganglion cell layer (GCL) damage was identified on OCT as an evident difference in foveal thickness and contour compared with a normal fovea or as asymmetry within the fovea. Fluorescein angiography was performed by confocal scanning laser ophthalmoscope (HRA 2; Heidelberg Engineering, Heidelberg, Germany), and FAZ damage visible during the FA arterial phase was graded according to the Early Treatment Diabetic Retinopathy Study (ETDRS) FA grading system. Correlations were sought between foveal GCL damage identified on OCT and FA capillary dropout sites. MAIN OUTCOME MEASURES Foveal GCL damage on OCT, the size of the foveola on OCT (defined as the area of GCL thickness <10 microm), ETDRS grading of FAZ on FA, and visual acuity. RESULTS Among the 124 eyes with diabetic retinopathy, 62 (50%) had FA evidence of either FAZ damage higher than grade 1 or FAZ capillary loss. In these eyes, damage to the FAZ seen on FA also could be detected on OCT (positive predictive value, 84.5%; negative predictive value, 72.9%), and locations of FAZ damage seen on FA corresponded well with sites of foveal GCL damage on OCT. In nondiabetic, normal eyes, the size of the foveola on OCT matched the size of the FAZ on FA. CONCLUSIONS Evidence of foveal GCL damage on OCT is a good indicator of macular ischemic damage in eyes with diabetic retinopathy. Although in this study FA was more sensitive than OCT in detecting vascular damage, OCT provides objective results and seems to be a good noninvasive substitute for FA.

Wound Leakage and Hypotony After 25-Gauge Sutureless Vitrectomy: Factors Affecting Postoperative Intraocular Pressure

BACKGROUND AND OBJECTIVE To investigate the factors related to postoperative hypotony after 25-gauge sutureless vitrectomy. PATIENTS AND METHODS Of 109 consecutive eyes undergoing sutureless vitrectomy, 95 fluid-filled eyes were randomly assigned to three groups according to the order of infusion cannula removal. In group 1 (30 eyes), the infusion was removed first. In group 2 (32 eyes), the infusion was removed after another cannula. In group 3 (33 eyes), the infusion was removed last. Intraocular pressure (IOP) was measured on preoperative day 1 and postoperative days 1, 7, and 30. RESULTS Mean age was 58.9 +/- 11.6 years (range: 18 to 80 years). Among each factor (including order of infusion removal, age, sex, axial length, preoperative IOP, previous vitrectomy, indications for vitrectomy and lens status), only age was significantly correlated with IOP on postoperative day 1 (P = .019). In 13 eyes in which hypotony persisted through postoperative day 2 (IOP < or = 5 mm Hg), the age of the patients was significantly younger than those who did not experience persisting hypotony (P = .006). CONCLUSION Younger patients were more likely to experience early postoperative hypotony.

Short-Term Safety and Efficacy of a Single Intravitreal Bevacizumab Injection for the Management of Polypoidal Choroidal Vasculopathy

Aims: To evaluate the short-term safety and efficacy of a single intravitreal bevacizumab injection in patients with polypoidal choroidal vasculopathy (PCV). Methods: The records of patients treated with intravitreal bevacizumab for PCV were retrospectively reviewed. All patients were evaluated by complete ophthalmic examination, optical coherence tomography and fluorescein and indocyanine green angiography. Changes in visual acuity and central retinal thickness (CRT) over 3 months were the main outcome measures. Results: Nineteen eyes of 18 patients were included. No serious ocular or systemic adverse events were observed. The median baseline visual acuity and CRT were 20/100 and 230 μm, respectively. After 1 month, there was no significant improvement in median visual acuity (20/80+1; p = 0.055), but median CRT had decreased significantly (160 μm; p < 0.001). After 3 months (data available for 17 eyes), both median visual acuity (20/63–2; p = 0.001) and CRT (190 μm; p = 0.007) showed significant improvements over baseline values. Conclusions: Intravitreal bevacizumab therapy for PCV was well tolerated over the 3-month follow-up period. Short-term results are promising, but further studies are necessary to evaluate long-term efficacy.

Co-occurrence of Acute Retinal Artery Occlusion and Acute Ischemic Stroke: Diffusion-Weighted Magnetic Resonance Imaging Study

PURPOSE To evaluate the co-occurrence of acute ischemic stroke and acute retinal artery occlusion (RAO). DESIGN Retrospective observational case series. METHODS We included 33 consecutive patients with acute RAO who underwent diffusion-weighted magnetic resonance imaging within 7 days of the onset of visual symptoms. The causes of RAO were classified according to the Trial of Org 10172 in Acute Stroke Treatment (TOAST) criteria, which are based on clinical features and the results of etiological evaluations for atherosclerosis, cardioembolism and other prothrombotic conditions. We evaluated the prevalence of accompanying acute ischemic stroke in subjects with acute RAO and examined the relationships with etiological parameters. RESULTS Acute ischemic stroke was detected in 8 (24.2%) subjects with RAO. Among these subjects, 3 (37.5%) patients did not exhibit any neurologic symptoms or signs. Most of the infarction patterns were small, multiple and scattered. All of the subjects with RAO who were positive for lesions on diffusion-weighted imaging had identifiable causes, whereas only 36% of the subjects who were negative for lesions had identifiable etiologies (P = .003). Carotid stenosis or cardioembolic sources were found more commonly in cases of central retinal artery occlusion (CRAO; 7/18, 38.9%) than in cases of branch retinal artery occlusion (BRAO; 1/15 6.7%, P = .046). CONCLUSIONS Acute cerebral infarctions frequently accompany RAO. We recommend diffusion-weighted imaging for patients with RAO because the presence of lesions on diffusion-weighted imaging is accompanied by a significantly increased probability of identifying the cause.

New insights into the pathoanatomy of diabetic macular edema: angiographic patterns and optical coherence tomography.

Purpose: To describe the pathoanatomy of diabetic macular edema in optical coherence tomography and its correlation with fluorescein angiography patterns. Methods: Sixty eyes of 56 patients were analyzed. Diabetic macular edema was classified into typical focal leakage (from microaneurysm), typical diffuse leakage (the capillary plexus), or combined/questionable leakage using fluorescein angiography and retinal thickness profiles. The leakage and pooling patterns in fluorescein angiography were matched to the corresponding optical coherence tomography images and analyzed. Results: Focal leakage shows swelling predominantly in the outer plexiform layer (OPL). Deeply located microaneurysms directly leak into the loose fiber portion of OPL (Henle layer) through the “fluid conductivity barrier” (synaptic portion of OPL). Diffuse leakage caused swelling predominantly in the inner nuclear layer and secondarily in the OPL. The deep capillary plexus is located between the two “fluid barriers” (inner plexiform layer and OPL); thus, diffuse leakage is primarily related with swelling in the inner nuclear layer. In the combined/questionable leakage, partial sections consisting of inner nuclear layer swelling and much larger areas of OPL/outer nuclear layer swelling are noticed. Conclusion: Based on the concept of the fluid conductivity barrier, we revealed a correlation between the intraretinal location of the leakage source and where the fluid accumulated within the retinal layers.

Repeated intravitreal injection of bevacizumab for clinically significant diabetic macular edema.

Purpose: Intravitreal bevacizumab (Avastin®) induces a transient improvement in diabetic macular edema, necessitating repeated injections. Here, we report the results of repeated administration of intravitreal bevacizumab for the treatment of clinically significant macular edema in 31 eyes of 24 patients. Methods: At preinjection and 1, 6, and 12 (±1) weeks postinjection, visual acuity (VA) with Early Treatment of Diabetic Retinopathy Study (ETDRS) and central macular thickness (CMT) evaluated using optical coherence tomography were compared with independent and paired t-tests. Results: VA and CMT were not significantly different before initial and repeated injections (administered at an interval of 22.06 ± 11.15 [SD] weeks). At 6 weeks after the first injection, VA increased significantly by 3.72 ± 8.02 ETDRS letters (P = 0.019), and CMT was markedly decreased by 93.30 ± 210.33 &mgr;m (P = 0.022), which returned to near baseline at 12 weeks. At 6 weeks after the second injection, VA increased significantly by 3.97 ± 7.46 ETDRS letters (P = 0.006) and CMT decreased considerably by 118.77 ± 178.58 &mgr;m (P = 0.001). At 12 weeks after the second injection, we observed a decrease in VA with recurrence of macular edema. Conclusions: Repeated administration of intravitreal bevacizumab (1.25 mg) may lead to the improvement of VA and CMT in patients with clinically significant macular edema.