Clinical application of anterior segment optical coherence tomography for angle-closure related disease

AbstractAnterior segment optical coherence tomography has the ability to acquire angle-to-angle cross-sectional anterior chamber images in a non-contact way, and this technology shows a good reproducibility for angle parameters. With the availability of image processing software, some novel anatomic parameters such as iris area, iris volume, anterior chamber area, anterior chamber volume, anterior chamber width, and lens vault have been evaluated for the diagnosis of angle-closure related disease. This review article will describe the definitions of these interior segment optical coherence tomography parameters and summarize recent findings about these parameters in diagnosing angle-closure disease

Scalable AOI-Cast for Peer-to-Peer Networked Virtual Environments

Networked virtual environments (NVEs) are computer-generated virtual worlds where users interact by exchang-ing messages via network connections. Each NVE user of-ten pays attention to only a limited visibility sphere called area of interest (AOI) where interactions occur. The dis-semination of messages to other users within the AOI (i.e., the AOI neighbors) thus is a fundamental NVE operation referred to as AOI-cast. Existing studies on NVE scala-bility have focused on system scalability, or the ability for the system to handle a growing number of total users, by using multicast or peer-to-peer (P2P) architectures. How-ever, another overlooked, yet important form of scalability relates to the handling of a growing number of users within the AOI (or AOI scalability). In this paper, we propose two AOI-cast schemes, called VoroCast and FiboCast, to im-prove the AOI scalability of P2P-based NVEs. VoroCast constructs a spanning tree across all AOI neighbors based on Voronoi diagrams, while FiboCast dynamically adjusts the messaging range by a Fibonacci sequence, so that AOI neighbors would receive updates at frequencies based on their hop counts from the message originator. Simulations show that the two schemes provide better AOI scalability than existing approaches. 1

Combined Tractional and Rhegmatogenous Retinal Detachment in Proliferative Diabetic Retinopathy in the Anti-VEGF Era

Purpose. To investigate the clinical features, surgical outcomes, and prognostic factors of combined rhegmatogenous and tractional detachment (combined RD) in proliferative diabetic retinopathy (PDR) in recent years. Methods. Medical records of PDR and combined RD treated with vitrectomy from 2008 to 2013 were retrospectively reviewed. Results. A total of 57 eyes from 49 patients were included. Nine eyes had received panretinal photocoagulation (PRP) and 7 eyes had intravitreal bevacizumab (IVB) within 3 months before RD developed. Thirty-eight eyes (66.7%) had ≧3 sites of broad adhesion of fibrovascular proliferation (FVP). Thirty-three eyes (57.9%) showed active FVP. Thirty-four eyes (59.6%) had extent of RD involving 3 or 4 quadrants. The primary reattachment rate was 93.0%, and the final visual acuity (VA) improved by more than 3 lines in 80.7% of eyes. Neovascular glaucoma occurred in 4 eyes postoperatively. Poor preoperative VA, severe vitreoretinal adhesion, and broad extent of RD had significant correlation with poor visual outcomes. Conclusion. PRP or IVB might play a role in provoking combined RD. The anatomical and functional success rates of surgery were high. Poor preoperative VA and severe proliferations predicted poor visual outcomes

Iron Behaving Badly: Inappropriate Iron Chelation as a Major Contributor to the Aetiology of Vascular and Other Progressive Inflammatory and Degenerative Diseases

The production of peroxide and superoxide is an inevitable consequence of aerobic metabolism, and while these particular "reactive oxygen species" (ROSs) can exhibit a number of biological effects, they are not of themselves excessively reactive and thus they are not especially damaging at physiological concentrations. However, their reactions with poorly liganded iron species can lead to the catalytic production of the very reactive and dangerous hydroxyl radical, which is exceptionally damaging, and a major cause of chronic inflammation. We review the considerable and wide-ranging evidence for the involvement of this combination of (su)peroxide and poorly liganded iron in a large number of physiological and indeed pathological processes and inflammatory disorders, especially those involving the progressive degradation of cellular and organismal performance. These diseases share a great many similarities and thus might be considered to have a common cause (i.e. iron-catalysed free radical and especially hydroxyl radical generation). The studies reviewed include those focused on a series of cardiovascular, metabolic and neurological diseases, where iron can be found at the sites of plaques and lesions, as well as studies showing the significance of iron to aging and longevity. The effective chelation of iron by natural or synthetic ligands is thus of major physiological (and potentially therapeutic) importance. As systems properties, we need to recognise that physiological observables have multiple molecular causes, and studying them in isolation leads to inconsistent patterns of apparent causality when it is the simultaneous combination of multiple factors that is responsible. This explains, for instance, the decidedly mixed effects of antioxidants that have been observed, etc...Comment: 159 pages, including 9 Figs and 2184 reference

The Knowledge Management Processes at Different Stages of Group Development

ABSTRACT Based on a developmental approach, this study intended to analyze the extent to which the different stages of group development differ regarding the use of knowledge management processes. The sample comprised 211 teams belonging to a Portuguese military organization. In order to test the hypotheses a multivariate analysis of variance was conducted. The results showed that more mature and cooperative groups (Restructuring/Realization phase) apply to a greater degree the processes of knowledge management, while groups in which there is high intragroup competition and in which members try to “gain power” among themselves (Reframing phase), apply these processes to a lesser degree

Influence of Myopia on the Humphrey Matrix Frequency Doubling Perimetry

台灣高度近視者比例之高是世界上其他國家少有的，因此高度近視引起的問題對身處台灣的眼科醫師是一項特殊的挑戰。由於高度近視者的眼軸拉長、視網膜遭受拉扯特別顯著，常被認為視覺功能與正視眼或低度近視者有所差別。為了確定高度近視者即使在確定無青光眼的狀態下，是否其視野檢查的表現仍較低、中度近視者差。關於這方面的研究並不多，尤其是第二代的Humphrey Matrix倍頻視野檢查計從未被評估過。因此，本研究的目的乃為了解不同近視程度是否會對第二代倍頻視野檢查的影響。而近視程度的劃分，係依據球面當量及眼軸長度兩種方式定義之。 本研究樣本共有91位、18至40歲之健康志願者參與。所有參與者需先接受眼壓測量、電腦驗光、最佳矯正視力檢驗、細隙燈檢查、眼底照相、中心角膜厚度及眼軸長度測量、及青光眼家族史、糖尿病病史詢問。如果有眼壓高於21毫米汞柱、視神經盤凹陷與視神經盤直徑比大於0.5、兩側視神經盤凹陷與視神經盤直徑比相差大於0.2、視網膜神經纖維層具有楔形或廣泛性缺損、患有糖尿病，則該名受測者的兩眼資料均排除。如果有最佳矯正視力未達1.0、散光超過2屈光度、曾接受眼科手術、白內障、角膜病變、視網膜病變，則該眼資料排除。通過篩檢者，繼續完成對比敏感度檢查及Humphrey Matrix倍頻視野C-30-2程式的檢查。我們依據球面當量及眼軸長度兩種定義，將受測眼分為低度近視組、中度近視組、高度近視組。由於同時將同一位受測者的雙眼資料均納入分析，所以我們利用線性混合模型之隨機效用（random effect）處理同一位受測者左右眼相關性的問題。利用線性混合模型（linear mixed model）檢驗三種近視程度組間視野指標（平均偏差值與型態標準偏差值）的差異及近視指標（球面當量與眼軸長度）與視野指標（平均偏差值與型態標準偏差值）的關係。最後，共有80位、151隻眼睛的資料納入分析。 受測者之平均年齡為29.6Purpose: Because the optic disc morphology of myopia is frequently similar to the glaucomatous disc, it is a challenge for ophthalmologists to differentiate myopia form glaucoma. Myopia-related visual dysfunction, which is considered as results of eyeball elongation or optic quality deterioration, may mimic other diseases such as glaucoma. This study is to evaluate whether high myopia patients may demonstrate poorer visual field results obtained from the Humphrey Matrix frequency doubling perimetry (FDP). Method: Ninety-one healthy volunteers between the ages of 18 to 40 were participated in this study. All subjects first received a whole panel of ophthalmic examinations including slit lamp exam, autorefraction, intraocular pressure, central corneal thickness, axial length measurement, and fundus photography. The subjects with diabetes, cataract, corneal opacity, retinal and neuro-ophthalmic pathology, cup-to-disc ratio greater than 0.5, bilateral cup-to-disc ratio asymmetry greater than 0.2, wedge or diffuse retinal nerve fibers defect, intraocular pressure greater than 21 mmHg, astigmatism greater than 2 diopters, and best corrected visual acuity less than 1.0 were excluded from the study. Eighty qualified subjects were further examined on contrast sensitivity and the Humphrey Matrix FDP full-threshold C30-2 program. Finally, onne hundred and fifty-one eyes from 80 subjects were included in data analysis. According to spherical equivalent and axial length parameters, we classified the subjects into low, intermediate and high myopia groups. Due to the correlation of right and left eye from the same subject, we used the randome effect of linear mixed model to capture the correlation. The mean deviation (MD), pattern standard deviation (PSD), and other variables obtained from the three groups were compared using linear mixed model. The association between the myopia indices (i.e. spherical equivalent and axial length) and the visual field indices (i.e. MD and PSD) were also analyzed by linear mixed model. Results: The average age of participated patients is 29.6目 錄 口試委員會審定書…………………………………………………………i 中文摘要………………………………………………………………… ii 英文摘要………………………………………………………………… iv 第一章 背景與研究動機……………………………………………… 1 第二章 文獻回顧……………………………………………………… 5 2.1. 倍頻視野檢查………………………………………………… 5 2.1.1. 倍頻幻象………………………………………………… 5 2.1.2.使用倍頻幻象的理由…………………………………… 6 2.1.3. 倍頻視野檢查對於青光眼診斷之幫助---早期診斷… 6 2.2. 影響倍頻視野檢查結果的因素……………………………… 7 2.2.1. 失焦……………………………………………………… 7 2.2.2. 學習效果……………………………………………… 10 2.2.3. 瞳孔大小…………………………………………………12 2.2.4. 白內障……………………………………………………12 2.2.5. 糖尿病……………………………………………………14 2.3. 近視對眼球特徵之影響………………………………………14 2.3.1. 瞳孔………………………………………………………14 2.3.2. 中心角膜厚度……………………………………………14 2.4. 近視對視覺功能之影響………………………………………15 2.4.1. 對視力的影響……………………………………………15 2.4.2. 對對比敏感度之影響……………………………………16 2.4.3. 近視對視野檢查之影響…………………………………19 2.4.3.1. 近視對傳統電腦視野檢查的影響………………19 2.4.3.2. 近視對倍頻視野檢查的影響…………………… 21 2.5. 名詞解釋…………………………………………………22 第三章 材料與方法……………………………………………………25 3.1. 研究設計………………………………………………………25 3.2. 研究對象………………………………………………………27 3.3. 樣本數估計……………………………………………………27 3.4. 篩選研究對象…………………………………………………27 3.5. 分組……………………………………………………………28 3.5.1. 依球面當量分組…………………………………………28 3.5.2. 依眼軸長度分組…………………………………………28 3.6. 檢查步驟………………………………………………………29 3.6.1. 基本檢查…………………………………………………29 3.6.2. 倍頻視野檢查進行方式…………………………………29 3.7. 變項之測量與紀錄……………………………………………30 3.7.1. 依變項之測量與紀錄……………………………………30 3.7.2. 自變項之測量與紀錄……………………………………30 3.8. 統計分析………………………………………………………33 第四章 結果……………………………………………………………34 4.1. 依球面當量分組之比較………………………………………36 4.1.1. 人口學與基本特徵之差異………………………………36 4.1.2. 對比敏感度之比較………………………………………38 4.1.3. 倍頻視野檢查結果相關資料之差異……………………38 4.1.4. 球面當量與視野指標（平均偏差值與型態標準偏差值） 之相關性分析……………………………………………43 4.1.4.1. 球面當量與視野平均偏差值之相關性分析……43 4.1.4.2. 球面當量與視野型態標準偏差值之相關性分析… …………………………………………………………50 4.2. 依眼軸長度分組之比較………………………………………57 4.2.1. 人口學與基本特徵之差異………………………………57 4.2.2. 對比敏感度之比較………………………………………57 4.2.3. 倍頻視野檢查結果相關資料之差異……………………60 4.2.4. 眼軸長度與視野指標（平均偏差值與型態標準偏差值） 之相關性分析…………………………………………………64 4.2.4.1. 眼軸長度與視野平均偏差值之相關性分析……64 4.2.4.2. 眼軸長度與視野型態標準偏差值之相關性分析………………………………………………………71 第五章 結論與討論……………………………………………………77 5.1. 主要之發現……………………………………………………78 5.2. 本研究的優點…………………………………………………80 5.3. 本研究的限制…………………………………………………81 參考資料…………………………………………………………………82 表目錄 表一、失焦對倍頻視野檢查之影響………………………………………9 表二、學習效果對倍頻視野檢查之影響………………………………11 表三、白內障對倍頻視野檢查之影響…………………………………13 表四、近視對對比敏感度之影響………………………………………17 表五、近視對傳統靜態電腦視野檢查之影響………………………… 20 表六、各空間頻率對比敏感度之對數單位轉換表……………………32 表七、低度、中度、及高度近視三組基本特質之差異（依球面當量分組）………………………………………………………………37 表八、低度、中度、及高度近視三組之對比敏感度之差異（依球面當量分組）……………………………………………………39 表九、低度、中度、及高度近視三組倍頻視野檢查結果相關資料之差異（依球面當分組）……………………………………………40 表十、球面當量與視野平均偏差值相關性之單變項分析（依球面當分 組）………………………………………………………………45 表十一（一）、影響視野平均偏差值因素之多變項分析（全部）…46 表十一（二）、影響視野平均偏差值因素之多變項分析（依球面當量分組，低度近視組）……………………………………………47 表十一（三）、影響視野平均偏差值因素之多變項分析（依球面當量分組，中度近視組）……………………………………………48 表十一（四）、影響視野平均偏差值因素之多變項分析（依球面當量分組，高度近視組）……………………………………………49 表十二、球面當量與視野型態標準偏差值相關性之單變項分析（依球面當量分組）……………………………………………………52 表十三（一）、影響視野型態標準偏差值因素之多變項分析（全部）………………………………………………………………53 表十三（二）、影響視野型態標準偏差值因素之多變項分析（依球面當量分組， 低度近視組）………………………………………54 表十三（三）、影響視野型態標準偏差值因素之多變項分析（依球面當量分組， 中度近視組）………………………………………55 表十三（四）、影響視野型態標準偏差值因素之多變項分析（依球面當量分組， 高度近視組）………………………………………56 表十四、低度、中度、及高度近視三組基本特質之差異（依眼軸長度分組）……………………………………………………………58 表十五、低度、中度、及高度近視三組之對比敏感度之差異（依眼軸長度分組）………………………………………………………59 表十六、低度、中度、及高度近視三組倍頻視野檢查結果相關資料之差異（依眼軸長度分組）………………………………………61 表十七、眼軸長度與視野平均偏差值相關性之單變項分析（依眼軸長度分組）…………………………………………………………66 表十八（一）、影響視野平均偏差值因素之多變項分析（全部）…67 表十八（二）、影響視野平均偏差值因素之多變項分析（依眼軸長度分組，低度近視組）……………………………………………68 表十八（三）、影響視野平均偏差值因素之多變項分析（依眼軸長度分組，中度近視組）……………………………………………69 表十八（四）、影響視野平均偏差值因素之多變項分析（依眼軸長度分組，高度近視組）……………………………………………70 表十九、眼軸長度與視野型態標準偏差值相關性之單變項分析（依眼軸長度分組）……………………………………………………72 表二十（一）、影響視野型態標準偏差值因素之多變項分析（全部）………………………………………………………………73 表二十（二）、影響視野型態標準偏差值因素之多變項分析（依眼軸長度分組， 低度近視組）………………………………………74 表二十（三）、影響視野型態標準偏差值因素之多變項分析（依眼軸長度分組， 中度近視組）………………………………………75 表二十（四）、影響視野型態標準偏差值因素之多變項分析（依眼軸長度分組， 高度近視組）………………………………………76 圖目錄 圖一、倍頻幻覺……………………………………………………………5 圖二、研究進行之流程圖………………………………………………26 圖三、球面當量與眼軸長度與之相關分布圖（全部）………………35 圖四、各組視野平均偏差值之盒狀圖（依球面當量分組）…………41 圖五、各組視野型態標準偏差值之盒狀圖（依球面當量分組）……42 圖六、視野平均偏差值與球面當量之相關分布圖（全部）…………44 圖七、視野型態標準偏差值與球面當量之相關分布圖（全部）……51 圖八、各組視野平均偏差值之盒狀圖（依眼軸長度分組）…………62 圖九、各組視野型態標準偏差值之盒狀圖（依眼軸長度分組）……63 圖十、視野平均偏差與眼軸長度之相關分布圖（全部）……………65 圖十一、視野型態標準偏差值與眼軸長度之相關分布圖（全部）…7

Intra-Examiner Repeatability and Agreement of Corneal Pachymetry Map Measurement by Time-Domain and Fourier-Domain Optical Coherence Tomography

To assess the intra-examiner repeatability and agreement of corneal pachymetry maps measured by time-domain (Visante OCT ) and Fourier-domain optical coherence tomography (RTVue OCT ). This observational cross- sectional study enrolled 72 eyes from 72 volunteers. Only one eye of each patient was chosen randomly to receive repeated scanning with both devices by the same examiner, in order to test the intra-observer repeatability. The first scan by each device from all enrolled eyes was used to analyze the difference and agreement between the two devices. The agreement between the two devices was analyzed by the Bland-Altman method. Intra- observer repeatability of each OCT device was analyzed by intra-class correlation (ICC). The mean corneal thickness of the central 2 mm zone was 524.3 +/- 35.7 A mu m and 525.4 A +/- 35.3 A mu m by the Visante OCT and the RTVue OCT respectively (p = 0.089). The intra-observer repeatability of the RTVue OCT (ICC = 0.994) was superior to that of the Visante OCT ( ICC = 0.989) in the central 2 mm zone. However, the intra-observer repeatability of the RTVue OCT in the pericentral 2 to 5 mm zone was not superior to that of the Visante OCT. Both OCT devices had similar repeatability in the pericentral 2 to 5 mm zone [ICC of the Visante OCT = 0. 991; 95% confidence interval (CI) 0.986-0.995), ICC of the RTVue OCT = 0.991; 95% CI 0.985-0.994)). The difference in CCT measurement by the Visante OCT and the RTVue OCT is probably too small to influence clinical decision making for refractive surgery and glaucoma management. The RTVue OCT demonstrated better intra-observer repeatability in the central 2 mm zone, which probably was related to its rapid image acquisition capability

Intraocular Formation of Heavy Oil in the Subretinal Space

Background: Heavy oil formation was found in the subretinal space in three patients with repeated vitreoretinal surgery. Cases: These patients had received perfluorocarbon liquid ( PFL) and silicone oil injection for retinal detachment in a previous surgery. Observations: A transparent " heavy density" oil bubble was found in the subretinal space in these patients. The heavy oil bubble was eventually removed by manual aspiration with a blunt-tipped 21-gauge needle. The retinas were reattached in all three cases. Conclusions: Silicone oil may mix with incompletely removed PFL to form heavy oil. During reoperation for persistent retinal detachment, these substances should be specifically sought and removed. (C ) Japanese Ophthalmological Society 2004