Ai Likun, Li Jing, Guan Huan, Wildsoet Christine F
Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing, China.
Invest Ophthalmol Vis Sci. 2009 Jan;50(1):295-304. doi: 10.1167/iovs.08-1972. Epub 2008 Aug 21.
To establish a chick model to investigate the trends of eye growth and emmetropization after early lensectomy for congenital cataract.
Four monocular treatments were applied: lens extraction (LX); sham surgery/-30 D lens; LX/+20 D lens; and LX/+30-D lens (nine per group). Lens powers were selected to slightly undercorrect or overcorrect the induced hyperopia in LX eyes and to induce comparable hyperopia in sham-surgery eyes. Refractive errors and axial ocular dimensions were measured over a 28-day period. External ocular dimensions were obtained when the eyes were enucleated on the last day.
The growth patterns of experimental (Exp) eyes varied with the type of manipulation. All eyes experiencing hyperopia initially grew more than their fellow eyes and exhibited myopic shifts in refraction. The sham/-30 D lens group showed the greatest increase in optical axial length, followed by the LX group, and then the LX/+20 D lens group. The Exp eyes of the LX/+30 D lens group, which were initially slightly myopic, grew least, and showed a small hyperopic shift. Lensectomized eyes enlarged more equatorially than axially (i.e., oblate), irrespective of the optical treatment applied.
The refractive changes observed in young, aphakic eyes are consistent with compensation for the defocus experienced, and thus emmetropization. However, differences in the effects of lensectomy compared to those of sham surgery raise the possibility that the lens is a source of essential growth factors. Alterative optical and mechanical explanations are offered for the oblate shapes of aphakic eyes.
建立雏鸡模型，以研究先天性白内障早期晶状体切除术后眼生长和正视化的趋势。
采用四种单眼治疗方法：晶状体摘除（LX）；假手术/-30 D晶状体；LX/+20 D晶状体；以及LX/+30-D晶状体（每组9只）。选择晶状体度数以略微欠矫或过矫LX眼诱导的远视，并在假手术眼中诱导相当的远视。在28天内测量屈光不正和眼轴尺寸。在最后一天摘除眼球时获得眼外尺寸。
实验（Exp）眼的生长模式因操作类型而异。所有最初出现远视的眼睛最初比其对侧眼生长得更多，并表现出近视性屈光变化。假手术/-30 D晶状体组的眼轴长度增加最大，其次是LX组，然后是LX/+20 D晶状体组。LX/+30 D晶状体组的Exp眼最初轻度近视，生长最少，并表现出小的远视性移位。无论采用何种光学治疗，晶状体切除的眼睛赤道方向比眼轴方向增大更多（即扁圆形）。
在年轻的无晶状体眼中观察到的屈光变化与对所经历的离焦的补偿一致，因此与正视化一致。然而，晶状体切除与假手术效果的差异增加了晶状体是重要生长因子来源的可能性。针对无晶状体眼的扁圆形形状提供了替代性的光学和力学解释。
