雙側人工水晶體植入後的兩眼不等視

　　　　　由於人工水晶體計算公式的改進，我們已經可以使手術前近視或遠視的 自內障病人，在術後得到接近正視的視力。因此理論上，兩眼術後應可得到平衡 的度數，但是在民國82年上半年長庚醫院212位兩眼均接受後房人工水晶體植入 的病人中，只有115位(54.2)的術後兩眼視差小於1.0 Diopter,有66位(31.1)的視差介 於1.0到2.0Diopter之間，有18位(8.5)介於2.0到3.0 Diopter之間，並有13位(6.1)的視 差大於3.0 Diopter;除了部份是由於故意造成的不等視，以方便病人一眼看遠，另 一眼看近外;術後的兩眼不等視可能造成病人視力矯正上的難題，同時也代表了 人工水晶體度數預測值的差異性。我們利用各種參數;包括兩次手術相隔時間， 第一次及部份第二次重做的術前角膜弧度值、眼軸由長度，人工水晶體，手術醫 師，及手術中是否產生併發症等各項變數來分析造成兩眼不等視的原因。並評估 以第一眼手術後的結果，來修正第二眼所要植入人工水晶體的度數，與實際產生 兩眼視差的比較。結果在大多數病例中，仍以目前第二眼參考線性回歸公式的人 工水晶體度數，術後產生較少的兩眼不等視。
　　　　　With the improvement of IOL power calculation,cataract patients may have near emmetropic visionafter surgery. Theoretically, the refraction of theirboth eyes should be equivalent in bilateral pseudo-phakia. However, among the 212 bilateral pseudo-phakia, with both eyes operated at CGMH and thesecond one operated during the first half year of 1993,only 115 (54.2) had less than 1.OD ofanisometropia,66 (31.1) between 1.0 D and 2.0 D, 18(8.5)between 2.0 D and 3.0D, and 13(6.1) higher than3.OD. Some anisometropia were resulted intentivelywith one eye for near vision and the other for farvision. On the other hand, anisometropia may cause problemes such as aniseikonia and anisophoria, andit may be resulted from the variance of implant powerprediction. Several parameters, including time-interval between two operations, data ofkeratometer,axial length, IOL type, surgeon, and vitreous loss,are analyzed to identify patients at higher risk foranisometropia. We also try to determine whether theresults of the first eye could be used to modify theimplant power selected for the second eye to reducethe risk of anisometropia. However, in most cases,simply using the value of the linear regressionpredictor for emmetropia in the second eye withoutmodifications minimized anisometropia.