新鏡頭暈的老問題 - 眼鏡

雙眼不等像的症狀不會有所謂的影像浮動描述..

我想您走錯了方向..


散光晃動的消除可以參考optical板 #1CPYq0ub篇..

畸變晃動的消除可以參考optical板 #1CqksOof篇..

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一般而言..大部分的視差患者配戴眼鏡不會有雙眼不等像的問題..

這就是物理模型knapp法則所預估的結果..

但您的視差太大..有可能會破壞物理模型的前提"視網膜受體分佈相同"..

建議進行雙眼眼底尺寸不等測試..一般眼科診所皆可進行..

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雙眼眼底像平衡(iseikonia test)

　　雙眼眼底像尺寸檢測原理是利用偏振片將雙眼視覺個別獨立出來，並利用融像環將個

別獨立的眼底像固定在同一區域，藉以方便患者進行雙眼眼底像尺寸主觀判定。


Iseikonia test(右眼影像)
http://www.wretch.cc/album/show.php?i=kramnik1&b=14&f=1210827357&p=29

iseikonia test(左眼影像)
http://www.wretch.cc/album/show.php?i=kramnik1&b=14&f=1210835502&p=31

iseikonia test(雙眼影像)
http://www.wretch.cc/album/show.php?i=kramnik1&b=14&f=1210827359&p=30


可以參考optical板 #1AbzvBz1篇,#1Aoh6G6T篇,#1Ap71VZm篇

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理想中的雙眼平衡應雙眼具有相同的視力，左右眼視網膜上成像的影像大小、形狀、

清晰度、對比度和各自反應出來的方位都相同。


對於視差患者之配鏡，傳統眼鏡行配置眼鏡會將雙眼之度數差異縮小，認為這樣可以

達成雙眼平衡中”左右眼視網膜上成像的影像大小相同”這項理念，然而這並不是完全正

確的。原因在於眼底像尺寸之判定並不單由”影像張角”這項因素所決定，而是與”眼軸

長度”，”視網膜受體分佈”，”皮質運作”許多因素所共同影響。



　　對於大部分近視視差患者(即純軸性近視患者)，直接採用Knapp’s法則成功率會相當

高。要執行精確的雙眼平衡，可以採用雙眼眼底像尺寸平衡檢測(iseikonia test)。

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Knapp’s法則

　　Knapp's Rule states that lenses placed at the anterior focal point of the

eye, generally 15 mm in front of the eye, will create similarly sized images

on the retina, whenever the disparity between the two eyes is due to a

difference in axial length of the eyes.


knapp’s法則說明當鏡片置於眼球的前焦點，通常在眼球前方15mm處，無論雙眼度數

上的差異為何，將會製造雙眼相同大小的眼底影像，原因在於雙眼眼軸長度之差異。



　　Knapp's rule, if the ametropia is entirely axial, corrective lenses

placed in the anterior focal plane of the eye will result in approximately

equal-size retinal image (iseikonia).


　　knapp’s法則，若屈光異常導因全是軸長因素，矯正鏡片置於眼球前焦點平面上將會

導致幾乎一樣大的眼底影像。



附註：物理模型說明對於純軸性遠視患者由於鏡片的形狀放大率效應(shape

magnification)將會導致Knapp’s法則失效。



相關實驗

correction of anisometropia by 顏美媛　　中華民國眼科醫學會雜誌 Vol.23


Foury-eight patients of simple and compound anisometropia were studied.

Axial length and lens thickness were measured with DBR-400. Corneal

refractive power was measured with keratometer. Aniseikonia was measured with

S. Awaya Aniseikonia test. Axial length was found to be the most important

factor in anisometropia. The average aniseikonia of 31 patients having

spectacles correction was 0.76%. Aniseikonia was also compared in 8 patients

having spectacles and contact lens correction. Spectacles correction produced

less aniseikonia than contact lens correction in axial anisometropia.



48位單純或複雜性兩眼不等視病人，以超音波DBR 400及角膜彎度計測其眼軸長度，水

晶體厚度及角膜屈光度。再以S. Awaya Aniseikonia test測其兩眼影像不等。發現兩眼

眼軸長度不相等乃構成兩眼不等視之主要因素。31位病人戴普通眼鏡矯正後兩眼影像不等

，平均為0.76%。本篇同時比較8位病人戴普通眼鏡及隱形眼鏡的影像不等情形，發現戴隱

形眼鏡後的影像不等較大。

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臨床檢測顯示對於近視高度視差患者，Knapp’s法則將會漸行失效，原因在於高度近視眼

球的視網網密度會降低。

A study of aniseikonia and Knapp's law using a projection space eikonometer.

by P Kramer, S Shippman, G Bennett, D Meininger and V Lubkin



METHODS: Thirteen patients with suspected axial anisometropia of at least 4

Diopters were identified, selected and examined. Cycloplegic refraction,

A-scan ultrasonic ocular biometry and Essilor Projection Space Eikonometry

were performed. RESULTS: Ten of the thirteen patients had their anisometropia

due primarily to ocular axial length differences. Of these ten, seven (70%)

had detectable levels of aniseikonia and 3 (30%) demonstrated no aniseikonia.

The other three patients whose aniso-metropia was due to combined axial and

refractive components, all had aniseikonia. CONCLUSION: As a geometric optics

theory, Knapp's Law stands on its own merits. However, in clinical practice,

reduction in retinal element density in high myopia limits its applicability.

Such patients often do have significant aniseikonia which can produce ocular

referable complaints and/or interfere with binocular vision. | PMID: 10553112

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