Ohmi S
Department of Ophthalmology, Wakayama Medical College, Japan.
J Cataract Refract Surg. 1993 Sep;19(5):640-3. doi: 10.1016/s0886-3350(13)80016-8.
An intraocular lens (IOL) may become displaced even when it has been implanted in the capsular bag. Asymmetric capsular shrinkage is one cause of lens decentration. To determine whether the IOL length influences the degree of decentration, we assessed the decentration of IOLs of different lengths in rabbits. After a D-shaped anterior capsulotomy that covered about half the area of an ordinary circular capsulotomy was performed in 19 eyes of ten white rabbits, a 14.0 mm IOL was fixated in the bag in one eye and a 12.5 mm IOL in the other eye. A circular anterior capsulotomy was performed in 16 eyes of eight controls and IOLs were similarly placed in the bag. Decentration of the 14.0 mm and 12.5 mm IOLs in the eyes with the D-shaped anterior capsulotomy did not differ eight weeks after the procedure. However, marked rotation from the initial position and decentration to the side opposite to that expected were observed in some eyes in which nodular opacification was observed. Both the 14.0 mm and 12.5 mm IOLs were markedly more displaced in eyes with the D-shaped anterior capsulotomy than in eyes with the circular anterior capsulotomy. These results confirm that asymmetric capsular shrinkage, which is affected by the anterior capsulotomy shape, influences post-operative IOL centration.
人工晶状体（IOL）即使已植入囊袋内也可能发生移位。囊膜不对称收缩是晶状体偏心的一个原因。为了确定人工晶状体的长度是否会影响偏心程度，我们评估了不同长度的人工晶状体在兔眼中的偏心情况。在10只白兔的19只眼中进行了D形前囊切开术，其覆盖面积约为普通圆形前囊切开术的一半，一只眼中将14.0mm的人工晶状体固定于囊袋内，另一只眼中固定12.5mm的人工晶状体。在8只对照兔的16只眼中进行了圆形前囊切开术，并将人工晶状体同样放置于囊袋内。手术8周后，D形前囊切开术眼内14.0mm和12.5mm人工晶状体的偏心情况无差异。然而，在一些观察到结节状混浊的眼中，观察到人工晶状体从初始位置明显旋转并向预期相反的一侧偏心。与圆形前囊切开术眼相比，D形前囊切开术眼内的14.0mm和12.5mm人工晶状体均明显更易移位。这些结果证实，受前囊切开术形状影响的囊膜不对称收缩会影响术后人工晶状体的居中情况。
