雙眼間的抑制程度與融像的關係

目的：本篇研究的目的在於探討健康成人形成雙眼視覺(Binocular Vision)的過程，有兩個重要的因素：融合影像(Fusion Image)與雙眼抑制(Binocular Suppression)，以下簡稱融像與抑制。雙眼有好的抑制現象才會有好的融像，建立更好的雙眼視覺表現。雙眼偏差(Binocular Disparity)的角度對融像或抑制有什麼樣的關係？方法：本研究招募41位受測者。一位男性受測者有先天性視網膜裂隙(Congenital Retinoschisis)的遺傳性疾病因而被排除。參與融像與抑制的檢查共40位受試者，年齡約20~30歲。男生24位平均年齡22.54±2.17，女生16位平均年齡22.19±1.94。測量兩個現象後做分析，第一測量抑制的現象，請受測者在雙眼同視檢查儀(Telebinocular，本研究自譯)的遠方（設定在20cm）看刺激卡的線條。此時左眼與右眼不同的刺激訊息會引起雙眼鬥視(Binocular Rivalry)，形成抑制現象，當水平單線浮顯時請受測者說“出現”，若不見了則請說“消失”，以碼錶紀錄雙眼抑制的累積時間與頻率。第二測量融像聚散力(Fusion Vergence, FV)的現象，測量遠方基底朝內(Base In, BI)和朝外(Base Out, BO)聚散力的模糊點(Blur point)總量（如果沒有模糊點改用破裂點(break point)）。最後進行融像聚散力與抑制的相關分析。 結果：較小的垂直雙線間距測得單線抑制的累積時間或頻率稍低（7''分角的抑制時間14.33秒; 頻率0.27次/秒），適當間距測得抑制的累積時間或頻率最多（14''分角的抑制時間14.68秒，29''分角的頻率0.308次/秒），更大間距測得抑制的累積時間或頻率更少（3˚52''分角的抑制時間4.45秒，頻率0.079次/秒最少）。單線抑制時間與FV之關係，在7''-t、14''-t和29''- t分角的抑制時間與FV有顯著差異（r=0.366, p=0.02; r=0.516, p=0.001; r=0.400, p=0.011）但是在較大間距58''-t 、1°57''-t和3°52''-t分角的抑制時間與FV則沒有顯著的差異（r=0.091, p=0.578; r=0.120, p=0.462; r=0.031, p=0.851）。水平單線抑制頻率與FV之關係在每個垂直雙線間距均沒有顯著性差異。結論：透過這次的研究發現，形成單一兩眼視(Single Binocular Vision)在適當的雙眼偏差較容易引起鬥視抑制現象，在較小或較多的雙眼偏差是依賴疊加融合現象。網膜中心凹的鼻側與顳側皆會產生融像知覺與鬥視知覺，同側性偏差(Uncrossed Disparity)物點位於感覺前平行面(Apparent Fronto-Parallel Plane; AFPP)之外，影像偏差在鼻側時容易引起融像知覺；交叉性偏差(Crossed Disparity)物點位於AFPP之內，影像偏差在顳側時容易引起鬥視知覺。融像知覺較弱的受測者，會導致輕微的立體視辨識困難，進而影響較小或較大間距的影像融合，然而在適當間距範圍內不受影響。

Purpose: It is the purpose of this study to explore the process of developing the binocular vision in healthy adults. There are two important factors, the fusion image and binocular suppression. The good binocular fusion is based on the suppression phenomena in order to create better binocular vision. What kind of relations are there between the angle of the binocular disparity and the fusion or with the suppression?Methods: There are 41 participants in this study. However, one of the male subjects who has retinoschisis was excluded. The average age of the 40 participants is 20~30 years old. 24 of the participants are male and 16 are female. The average age of the male group is 22.53±2.17 and for the female group the average age is 22.19±1.94. There are two measurements in the project, which are both followed by analysis. Firstly, to measure suppression phenomena by having the test subjects look at the line of the stimulate card in the Telebinocular, setting the distance at 20 cm. When there are two different stimulation signals between the right and the left eyes, the binocular rivalry appears, which will induce the suppression phenomena. When seeing a horizontal single line, the test subjects need to say “appear”; when the line disappears, they need to say “disappear”. At the same time, we use the timer to record the suppression’s accumulation time and frequencies. Secondly, to measure the Fusion Vergence (FV) by measuring the amount of the distance base in (BI) and base out (BO) vergences at blur point (if no blur point, use break point). Finally, to carry out the analysis on the results of the FV and suppression.Results: With the smallest vertical double-line spacing, the suppression’s accumulation time or frequencies are slightly lower (the suppression time of the 7'' angle was 14.33 seconds; the frequency was 0.27 times/second). With the appropriate spacing, the suppression’s accumulation time or frequencies are the highest (the suppression time of 14'' angle was 14.68 seconds and the frequency of the 29'' angle was 0.308 times/second). With the largest spacing, the suppression’s accumulation time and frequencies are the lowest (the suppression time of the 3 ̊52'' angle was 3.45 seconds and the minimum frequency of 0.079 times/second). The relationship between the single-line suppression’s accumulation time and the FV has statistically significant differences at 7''-t, 14''-t and 29''-t. (r = 0.366, p = 0.02; r = 0.516, p = 0.001; r = 0.400, p = 0.011). However, there is no significant difference between the suppression’s accumulation time and the FV at 58''-t, 1°57''-t and 3°52''-t, with large spacing (r=0.091, p=0.578; r=0.120, p= 0.462; r=0.031, p=0.851). In addition, there is no significant difference between the horizontal single-line suppression frequencies and the FV in every spacing configuration.Conclusion: The findings of this study are with the appropriate binocular disparity to achieve single binocular vision is through relying on the binocular rivalry phenomena and with the smaller and larger binocular disparities, it relies on the fusion phenomena. The fusion and rivalry perceptions appear in the fovea of retina’s nasal and temporal sides. The uncrossed disparity is when the subject is outside the Apparent Fronto-Parallel Plane (AFPP). As a result, the image disparity falls on the nasal side, which could induce the fusion perception. The crossed disparity is when the subject is inside the AFPP. Consequently, the image disparity falls on the temple side, which could induce the rivalry perception. For the test subjects with weak fusion perception, they have difficulty identifying the stereo vision, which affects the fusion with the larger and smaller spacing configurations. However, with the appropriate spacing, the rivalry perception is not affected.