Boisvert Chantal, Beverly David T, McClatchey Scott K
The University of New Mexico Health Sciences Center, Albuquerque, New Mexico, USA.
J AAPOS. 2009 Dec;13(6):555-7. doi: 10.1016/j.jaapos.2009.10.001.
The normal growth of a young child's pseudophakic eye can result in a large myopic shift. Temporary polypseudophakia using piggyback intraocular lenses (IOLs) has been proposed as a means to reduce the amount of myopic shift by removing the anterior IOL when the eye becomes sufficiently myopic. Since the rate of refractive growth can be used to predict the refractive curve over time in pseudophakic children, we used this knowledge to develop a theoretical strategy for choosing IOL power combinations for temporary polypseudophakia.
We used a novel Pediatric Piggyback IOL Calculator to develop a strategy for choosing the powers of the anterior and posterior IOLs. We graphed the predicted results for several combinations of piggyback IOL powers and chose the combination of IOL powers that appeared to give the best results, based on the known rate of refractive growth (5.4 D) and its standard deviation (2.4 D). We aimed for a combination to minimize the hyperopic or myopic refractive error during the first 6 years of life to facilitate amblyopia management and minimize the refractive error at age 20 years.
We found optimal results when the initial postoperative goal refraction with polypseudophakia was moderate hyperopia and the anterior IOL had approximately 20% of the total required IOL power.
This theoretical strategy can be used to determine piggyback IOL powers to use in children.
幼儿假晶状体眼的正常生长可导致较大的近视性屈光变化。有人提出使用背驮式人工晶状体（IOL）形成临时多焦点人工晶状体，作为当眼睛出现足够近视时通过移除前部IOL来减少近视性屈光变化量的一种方法。由于屈光生长速率可用于预测假晶状体儿童随时间的屈光曲线，我们利用这一知识制定了一种为临时多焦点人工晶状体选择IOL屈光度组合的理论策略。
我们使用一种新型的儿童背驮式IOL计算器来制定选择前部和后部IOL屈光度的策略。我们绘制了几种背驮式IOL屈光度组合的预测结果，并根据已知的屈光生长速率（5.4 D）及其标准差（2.4 D），选择了似乎能给出最佳结果的IOL屈光度组合。我们的目标是找到一种组合，在生命的前6年将远视或近视屈光不正降至最低，以利于弱视治疗，并使20岁时的屈光不正最小化。
我们发现，当临时多焦点人工晶状体术后初始目标屈光为中度远视且前部IOL具有所需总IOL屈光度的约20%时，可获得最佳结果。
这一理论策略可用于确定儿童使用的背驮式IOL屈光度。
