PL4-1

　　Management of Glaucoma in Latin-America

　　Maul

　　Chili

　　PL4-2 
              
　　E世代台北學童近視度數增加之危險因子

　　鄭永豐

　　台北眼科醫學會理事長

　　目的：一、探究e世代促使近視惡化的危險因子
二、e世代是否存在新的近視危險因子(近視因子之排序予相互作用為何？)

　　(e)方法：一、研究假說：1、假設自變項為多重近視危險因子(multivariate)：

　　X1 ：e化產品使用，X2：閱讀時間，X3：閱讀距離，影響依變項Y近視度數增加。2、假設危險族群與一般近視學童組(對照組)近視度數增加Y與危險因子X之間的關係，兩組有明顯差異。

　　二、研究方法：針對台北市內153間國小六年級生共1,096班32,293人抽樣，抽取五個學校六年級全班級全數學生共1,063人作問券調查，有效問券1,056人，問卷內容(共191題，分6部份)針對自變項X：遺傳、環境、行為、以及人口學的特質等等，與依變項Y：是否有近視與近視度數增加的關係。

　　三、分析方法：以統計方法：線性迴歸分析(general linear models)、多變項迴歸分析(multiple regression models)、對數迴歸分析(logistic regression models)、卡方Chi-square、Student t-test or ANOVA─檢視X與Y之間的關係，與不同危險程度的各組學生之間，其眼屈光度數值有否達統計上顯著差異。

　　結果：一、台北e世代學童，e化產品：電腦、電玩、手機等影響視力越來越重，與傳統的危險因子加乘。

　　二、e化產品使用為台北e世代學童近視惡化的危險因子。

　　三、高危險族群較一般近視學童，e化產品造成近視惡化有顯著差異。

　　結論：e世代學童是否有近視與近視度數的增加關係與危險因子：e化產品使用、閱讀時間、閱讀距離、躺臥閱讀與閱讀的間斷休息時間成正相關關係。

　　PL4-3

　　角膜地形图- 波前时代的临床应用

　　王明旭

　　中国爱尔眼科医院集团屈光手术主任

　　本讲座将介绍现代角膜地形图的科学原理，角膜地形图的使用，介绍正常和病理的角膜地形图角膜形态，在屈光手术前和屈光手术后并发症的角膜地形图。重点在对类似圆锥角膜角膜形态（FFKC）的鉴别，如何正确测量角膜后表面，厚度以及高度的改变的阐述。这部分将深入地探讨角膜地形图对在一些屈光手术中碰到的圆锥角膜的临床指导。然后讲述以角膜地形图为基础的个性性治疗给即将来到的角膜地形图和波前像差技术结合的屈光手术和角膜手术中时代带来的新的技术。讲座将阐述角膜地形图和波前像差技术的关系和临床相关性。论述以角膜地形图和波前像差技术结合为基础的治疗方法。这部分的目的是使读者对这两个技术结合应用有一全新的认识，不仅在科学理论方面，还有在临床应用方面的理解，给予角膜地形图和波前像差技术结合的个性性治疗临床的指导。讲座还将介绍具体的角膜地形图系统的工作原理和临床应用以及当今在市场具有代表性的每一类角膜地形图仪，不仅包括传统角膜地形图仪如Placido环系统（Humphrey Atlas， Magnllan Mapper， Tracey-EyEsys， Optikon， Tomey ，Topcon），地形高度型角膜地形图，裂隙扫描型角膜地形图的全面的临床指导教科书，而且还讲述新一代角膜角膜地形图如超生角膜地形图（Artemis），三维角膜地形图（AstraMax）以及最新的360旋转裂隙型角膜地形图（Pentacam，Precisio）的临床指导。最后，讲座将提出对将来角膜地形图技术的展望：通过对各种技术的结合，我们希望将来的视觉手术真正能够到达最完美的境界，让术后的病人有最佳的视觉质量，不再有因为手术而引起的像差。

　　PL4-4

　　Issues about angle closure glaucoma

　　Steve Seah

　　National Eye Center,Singapore

　　PL4-5

　　Optimising Parameters for  Torsional ultrasound in Phacoemulsification

　　Charith Fonseka

　　Eye Hospital Colombo, Sri Lanka

　　Purpose – To compare linear vs fixed torsional ultrasound in phacoemulsification
Methods – 90 consecutive eyes of patients scheduled for cataract surgery were randomly allocated into two groups (A & B) . All eyes underwent phacoemulsification using a Alcon Infiniti system using torsional ultrasound. Parameters were fixed 600 for vaccum 134cm for  irrigation bottle height ,42ml/min for flow rate and amplitude of stroke at 100%. Eyes in group A torsional ultrasound was linear , and for B it was fixed. In the event of needle clogging a switch was made traditional ultrasound until the needle was clear. The Age, laterality, cataract density, were recorded . Outcome was measurements were  duration of procedure , frequency of clogging of needle, CDE.

　　Results – There was no statistically significant difference between the two groups for age , lataerality and grade of cataract. There was a highly significant difference between the two groups with all outcome measurements being more in group A.

　　Conclusion – Fixed ultrasound resulted in lower US energy utilization as well as shorter procedure times and virtually eliminates clogging.

　　PL4-6

　　Giant Retinal Tear – An Asian Perspective

　　Ang Chong Lye   
   
　　Director, Singapore National Eye Centre    

　　Senior Consultant, Vitreo-Retinal Service   
 
　　Historically, results from giant retinal tear (GRT) surgery have been poor. This can be due to the inability to unroll the inverted retinal flap, proliferative vitreoretinopathy and slippage of the retina.

　　Vitrectomy techniques, coupled with the use of ‘heavy liquids’, endolaser and wide-field panaromic viewing devices have improved surgical results considerably.

　　We report the results of 128 eyes of 124 patients managed by vitreous surgery techniques from 1991 to 2005 in the Singapore National Eye Centre.
Final retinal detachment was achieved in 84.8% of eyes, 71.7% in one surgery and 13.1% requiring repeat surgery for final success. Forty one percent of eyes were able to achieve 6/12 or better vision after six months followup.

　　Modern vitreous surgery, with the use of various surgical armamentaria has improved the outcome of GRT surgery.

　　PL4-7

　　The impact of pupil center shift and decentered ablation on Higher Order Aberration after wavefront-guided refractive surgery. 

　　Kuang-mon A. Tuan OD, PHD, FAAO, David C. Chang MD, MPH
Santa Clara, CA, USA; Taipei, Taiwan

　　Purpose: To apply an established analytical model to examine the influence of wavefront diameter change and pupil centroid shift on ocular aberrations to predict the impact of small shifts in wavefront centration caused by pupil centroid shift on clinical outcomes.

　　Method: Analytical reconstruction of Zernike polynomials was used to study the changes in Zernike coefficients that occur when pupils change size, when pupil centers shift, and when ablations are not precisely registered.  Experimental data and clinical outcomes were used to validate the model. Single center, single surgeon data were used to assess the impact of iris registration (IR) technology, which is designed to increase ablation accuracy. Of 130 patients, 63 had IR, and 67 did not have IR during their surgeries.

　　Results: Analytical modeling showed that as a pupil constricts, higher order aberrations change to lower order aberrations of the same family. For example, as the pupil constricts, Z24 (secondary spherical aberration) changes to  Z12 (primary spherical aberration) and Z4 (defocus/sphere). An eye showing high positive spherical aberration (SA) in the wavefront measurement may show more positive sphere in the manifest refraction due to pupil constriction.

　　The model also showed that imprecise registration of a wavefront-guided treatment to correct dominating coma or cylinder results in residual coma and cylinder and induces SA and spherical defocus. Imprecise registration of a primarily spherical (defocus or SA) correction reduces the effectiveness of spherical correction while inducing cylinder and coma as a side effect. 

　　Clinical results supported the analytical model. Post-surgical comparison of the patients that received IR to the patients that did not receive IR showed significant improvement in spherical aberration and coma terms and less residual sphere, cylinder, spherical aberration, and coma. The patients in the IR group experienced 32% more post-op emmetropia, and 18% more 20/16 (or 1.25) uncorrected vision. Astigmatic eyes and high HOA eyes in the IR group had better results than astigmatic and high HOA eyes in the non-IR group.

　　Conclusions: We have shown how analytical modeling can be used to better understand the dynamics of wavefront aberrations and their consequences to clinical outcomes. An imprecisely registered ablation reduces the effectiveness of higher order correction and induces neighboring aberrations. Wavefront-guided laser vision correction with IR technology produced better surgical outcomes and required fewer retreatments than treatments not using IR technology. In this study we have shown the importance of accounting for shift in pupil center and cyclorotation and the necessity of precise ablation registration for improved clinical outcomes.

　　PL4-8

　　Soluble EphB4 –a new inhibitor for choroidal neovascularization

　　S. He, R. Subramanyan, V. Krasnoperov, Y. Kim, D. Zhu, E.A. Barron, A. Rodriguez , S.J. Ryan, P.S. Gill, D.R. Hinton
Departments of Pathology, Ophthalmology, and Medicine, Keck School of Medicine at University of Southern California; and the Doheny Eye Institute, Los Angeles, CA and Vasgene Therapeutics, Inc, Los Angeles,CA

　　Purpose:  EphB4 receptor and its ligand (EphrinB2) are critical regulators of cell adhesion, growth, migration and vascular assembly. Recombinant soluble form of EphB4 extracellular domain (sEphB4) inhibits vessel maturation and angiogenesis. The purpose of this study was to evaluate the effect sEphB4 receptor on the regulation of choroidal endothelial cell (CEC) and retinal pigment epithelial cell function (RPE) cell function and the inhibition of laser induced choroidal neovascularization (CNV). Methods: Early passage bovine CEC and human fetal RPE cells were used in the study. Effect of sEphB4 on PDGF or VEGF induced CEC and RPE migration was evaluated using a Boyden chamber assay. Attachment was assayed using a modified MTT assay in 96-well plates. CEC tube formation was performed in matrigel. The expression of focal adhesion kinase (FAK) was analyzed by using confocal microscopy. Activation of MAPK was determined by Western blot after RPE cells were exposed to sEphB4 for 24 hours. Focal laser photocoagulation was used to induce choroidal neovascularization in Brown Norway pigmented rats. sEphB4 (0.1, 0.3, 1 or 3 micrograms), or vehicle was injected into the vitreous, 3 and 7 days after laser photocoagulation. Fluorescein angiograms (FA) and histological examinations were performed at day 14 after laser surgery. Result: sEphB4 reduced CEC and RPE migration. Similarly, sEphB4 inhibited RPE attachment and CEC tube formation in a dose-dependent manner. Expression of FAK was reduced after exposure to sEphB4 at a concentration of 3ug/ml. PDGF-induced MAPK expression was inhibited in the presence of sEphB4 at a dose of 1ug/ml and above. sEphB4 injection resulted in a dose-response inhibition of leakage during FA. Preliminary histological studies reveal that eyes injected with the highest dose of sEphB4 show decreased vascularity in the CNV lesions.
Conclusion: sEphB4 regulates CEC and RPE function in vitro. Laser induced CNV was inhibited by the injection of sephB4 in rat vitreous.

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