- 學位論文
屈光度低估之成年人視覺功能分析
Influence of visual functions in the adult population with underestimated refractive power
摘要
近視高盛行率在全球都是備受關注的議題，高度近視的比率也越來越高。而高度近視容易併發其他眼相關的疾病，臨床上近視程度的追蹤對於眼疾病預防是重要的一環。等價球面度數是目前臨床上追蹤近視患者常用的方式，但是在某些族群可能會有近視度數被低估的情況出現。本研究評估近視度數低估族群的眼球參數、視覺功能、光學像差和眼底攝影等數據，來協助對於近視低估族群的判別。 本研究為橫斷性研究，共37名（20至30歲）近視度數介於-3.00 D至-6.00 D的健康成年人參與，數據的收集分為四部份：眼屈光檢查、眼睛參數測量、視覺功能檢查和光學像差分析。眼屈光檢查包含屈光度量測及眼睛健康狀態的評估，眼睛參數則測量角膜曲率半徑、前房深度、眼軸長度以及眼底影像拍攝，視覺功能部分評估了對比敏感度及其他單眼、雙眼視的視覺功能表現，光學像差則分析高階像差的差異。 研究結果發現低估組與控制組在等價球面度數上並無統計上差異，但低估組在統計上有較平角膜曲率(p < 0.001)、較深前房深度(p < 0.05)及眼軸長度(p < 0.001)。另外，低估組眼底影像神經纖維缺失有較高的比例(p = 0.001)；像差方面，低估組的彗星像差在統計上較低(p < 0.05)，球面像差則是在統計上呈現較高(p < 0.05)。而兩組在視覺功能上，低估組在調節幅度、立體視和對敏感度都有較差的趨勢，但還未達到統計上顯著的差異。控制組在等價球面度數與眼軸長(r = -.495, p < 0.001)、角膜曲率半徑(r = .431, p < 0.001)以及AL/CR ratio(r = -.696, p < 0.001)都有顯著相關，但低估組只有眼軸與角膜曲率比值和等價球面度數有顯著負相關性(r = -.550, p < 0.001)。 儘管在等價球面度數上兩組之間並沒有明顯差異，但透過其他的指標可以發現低估組的近視程度與控制組不同且更接近高度近視。臨床上只使用單一的指標（如：等價球面度數）是無法明確表示患者的近視狀態。評估近視程度時應搭配眼軸長、眼底影像測量或是加入AL/CR ratio的方式來了解病患的近視程度與進展。另外近視程度的差異會導致視覺功能表現的不同，搭配視覺功能檢查的結果，才能夠更了解患者實際的屈光狀態。
並列摘要
Purpose The high prevalence of myopia is a global issue nowadays Thus, monitoring for the myopic status becomes an important role in preventing the myopia-induced complications. Spherical equivalent refractive power (SER) is the most common approach to quantify the changes in refractive development. However, ocular refractive status would be affected by the corneal curvature and axial length in some cases. Therefore, refractive power might be underestimated if it was merely determined by SER. The aim of this study is to compare the differences in physiological features, visual function and ocular aberration between the control group and the underestimated refractive power group. Method 54 healthy participants aged 20 to 30 years (SER range: -3.00 to -6.00D) were recruited and divided into the control group and the underestimated refractive power group. Objective refractions were measured by using the open-field autorefractor with viewing a distant target for accommodative relaxation. The corneal radius (CR), axial length (AL) and anterior chamber depth (ACD) were measured via using the IOL master. Fundus photography was captured with the non-mydriatic fundus camera. Visual function and ocular aberration were also evaluated. Result The data of 74 eyes (40 from the control group, 34 from the underestimated group) were analyzed. The SER had no significant differences between the two groups. Significant differences in AL (control group vs underestimated group, 25.06 ± 0.45 vs 26.40 ± 0.59 mm, p < 0.001) and CR (control group vs underestimated group, 7.69 ± 0.16 vs 8.08 ± 0.15 mm, p < 0.001) were found between the two groups. There were no significant differences in visual functions between two groups apart from the better results for the distance negative fusional vergence (p = 0.023) and stereoacuity (p = 0.031) in the control group. Furthermore, the root mean square (RMS) value of spherical was higher in the control group (p = 0.039). On the other side, comma aberration was lower in the underestimated group (p = 0.029). Additionally, the underestimated group showed a higher incidence of retinal nerve fiber layer defect (p = 0.001, OR = 5.97, 95% CI = 2.07 – 17.24). The SER was significantly correlated with AL (r = -.495, p < 0.001), CR (r = .431, p < 0.001) and also AL/CR ratio (r = -.696, p < 0.001) in the control group. However, significant correlation of SER was only found to AL/CR ratio (r = -.550, p < 0.001) in the underestimated group. Conclusion Although the average of SER is similar between the two groups, the myopic status of the underestimated group is similar to high myopes. Refractive status could not be determined merely by using spherical equivalent, especially in those who have flat corneas. The AL/CR ratio would be a more reliable indicator in predicting refractive status than SER. Therefore, the combination of AL measurement and fundus photography is suggested for defining the real refractive status.