本篇文章用模形式推导说明: (1)morgan与oep之相关异向补偿融像运动极值测试数据， 远用内集情况之模糊点为accomodation limit模糊状态； 　 近用内集,远用外散,近用外散情况之模糊点为vergence limit模糊状态； (2)Cmax < 25.5Δ #测量值为36Δ(morgan系统)， Cmax < 22.2Δ #测量值为31.7Δ(OEP系统) Cmin > -4.5Δ #测量值-6.4Δ (morgan系统)， Cmin > -5.9Δ~-6.74Δ #测量值为-8.4Δ~-9.6Δ(OEP系统) (3)sheard criterion和percival criterion必须在单眼mpmva处方下进行才有意义 (4)在远用处方下，sheard criterion和percival criterion建议量值一致 两者为等效准则.. (5)在近用处方下，对於外斜患者斜位量修正建议量 sheard criterion建议量 > percival criterion建议量 差异约 {0.5Δ+ [(6-A)/3]*(1/工作距离)} (6)在近用处方下，对於内斜患者斜位量修正建议量 　 sheard criterion建议量 < percival criterion建议量 差异约 {- 0.5Δ- [(6-A)/3]*(1/工作距离)} 以上近用条件为工作距离设定为 16 inch ============================================================================ 相关实验数据论文连结:http://www.opt.indiana.edu/IndJOpt/ijofall05.pdf 论文名称:Comparison of Methods of Prescribing Lateral Prism Power in Non-Strabismic Subjects 作者:David A. Goss, O.D., Ph.D. 摘录: Sheard's criterion and Percival's criterion results were also quite closely related in this study. Sheard's criterion, based on the dissociated phoria and the compensating vergence, often yields more prism in symptomatic individuals with exophoria than Percival's criterion, which is based on the balance between the vergences. Percival's criterion often suggests more prism in symptomatic individuals with esophoria than Sheard's criterion. ============================================================================== Sheard criterion (外斜) P = (2D - R) / 3 D = the magnitude of the dissociated phoria, R = the base-in blur (break if no blur occurred) inesophoria or the base-out blur (break if no blur) inexophoria, P = Sheard's criterion prismamount. A negative P value, indicating that Sheard's criterion was met, was included in thedata analysis as a zero value because no prismwould be recommended . 单眼所需棱镜度 = (2/3) *斜位 – (1/3)单眼相关补偿融像异向运动 example: pat 10 base out exo tropia，异向运动 12BO 需矫正量为 P = (2/3)*10 – (1/3)*12 = 2.64 (BI) #此例子只是方便理解，并不代表此例子合乎实际 ========================================================================= Percival criterion (外斜) P = (G - 2L) / 3 G = the greater of the two lateral fusional vergence limits (base-in or base-out), L = the lesser of the fusional vergence limits, P = Percival's criterion prism amount. A negative Pvalue, indicating that Percival's criterion was met,was considered to be a zero value for analysisbecause no prism would be recommended.. 单眼所需棱镜度 = (1/3)较大单眼补偿融像异向运动 – (2/3)较小单眼补偿融像异向运动 example: pat ，异向运动 12BO,5BI 需矫正量为 P = (1/3)*12 – (2/3)*5 = 2 (BO) #此例子只是方便理解，并不代表此例子合乎实际 ============================================================================== 证明： 采用morgan与oep实验数据，模型式推导出(1)与(2) http://www.wretch.cc/blog/kramnik1/13654279 用模型式可以轻易推导出在双眼mpmva情况下， 再使用棱镜加入建议量公式是无意义的，推导出(3) #略 以上述推导结果为根基，可进一步推导出(4) http://www.wretch.cc/blog/kramnik1/13674852 对於近用处方，可以推导出(5)与(6) http://www.wretch.cc/blog/kramnik1/13674856 -- 附注:论文连结内文有提到，不论对於外斜还是内斜患者， 　　 大部分的视光师对於sheard criterion比较有信心.. --

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