請教Sazana大關於兩眼視覺問題 - 眼鏡

※ 引述《kramnik ( )》之銘言：
: http://arapaho.nsuok.edu/~salmonto/vs3_materials/Lecture9.pdf
: 我想您誤會這圖的意義了..
: 60%不代表是eso fixation disparity占了60%
: 而是type 1 的走向圖型(縱軸FD,橫軸prism added)占了60%

或許吧，但我看到的書上大部分所列的四種類型圖形都是這麼畫的

中點在eso方向

包括Borish's clinical refraction(Borish)
Foundations of Binocular Vision(Steinman)
而有些書是將type I的中點畫在0的地方如primary care of optometry

且
Vision Science III - Binocular Vision Module
Lecture 9 - Fixation Disparity Types

節錄
Some references, including Steinman (p. 61), say that associated and
dissociated phoria are usually of the same direction, but others say that
they are rarely the same (Borish).

為了證實我再去翻一下他們的書，
Steinman的原文是說分離性斜位與FD的方向一般
是相同的，但這只是通則，有時會出現相反的情形。

而Borish的原文
In actuality, the associated and dissociated phorias are
rarely of the exact same magnitude and direction.
Sheedy and Saladin, working with the horizontal
system, showed that different mechanisms were in oper-
ation during fused (associated) and unfused (dissoci-
ated) measurements. Under fused conditions, complex
interactions occur between the disparity vergence and
accommodative systems. The state of SVA in operation
may be different when the phoria and fixation disparity
measurements are made. Finally, some innervations not
controlled by feedback (e.g., those due to volition, prox-
imity, or base-level tonicity) could be in a different state
of excitation when the two types of phoria measure-
ments are performed.

: 我們只能說對於大部分的案例..下句是成立的..
: "若帳面上呈現眼位外斜..其會呈現exo fixation dispartiy..代表內集輻輳壓力..
: 給予BI稜鏡可以降低exo fixation disparity..降低內集輻輳負擔..反之則反.."

綜合以上，我的看法是

若將FD解釋為視覺系統的壓力表現，則對於大多數視覺系統正常且壓力不大的對象而言，

分離性斜位與FD方向相同是成立的。

反之若視覺系統異常或視覺系統正常但有異常壓力的人，則有時會出現異常的結果。

對大量斜位患者且有症狀者，較沒有疑問的是，

分離性斜位分析與FD分析的方向會相同，但FD所指示的值會較小。

而小量斜位但有症狀者，則分離性斜位分析可能與FD分析的量值與方向都會有所不同。

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