Shih Y F, Fitzgerald M E, Reiner A
Department of Ophthalmology, National Taiwan University Hospital, Taipei.
Invest Ophthalmol Vis Sci. 1994 Sep;35(10):3691-701.
To determine the role of the choroidal and ciliary nerves and the functions they control, choroidal blood flow (CBF) and accommodation-pupil diameter, respectively, in myopia induced by form-vision deprivation.
Three groups of chicks were studied: chicks with choroidal nerves cut in the right eye, chicks with ciliary nerves cut in the right eye, and sham control chicks that received the same surgical preparation but no nerve cuts. A plastic, dome-shaped goggle was glued over the right eye of birds in all three groups after orbital surgery, and, 2 weeks later, CBF was measured using laser Doppler flowmetry. Refractive status was then measured using streak retinoscopy, and axial, nasotemporal, and dorsoventral lengths were measured using vernier calipers after enucleation. The eyes were also weighed.
In the sham control birds, considerable ocular enlargement in all dimensions and a high degree of myopia (-14.68 diopters) was observed in the goggled eye, and CBF in the goggled eye was 66% of that in the nongoggled eye. In birds with choroidal nerve cuts, the degree of enlargement of the goggled eye was less in all dimensions, and the myopia in the goggled eye (-4.74 D) was attenuated compared to that observed in the sham controls. CBF in the goggled eye was 21% of that in nongoggled eye. Finally, in the birds with ciliary nerve cuts, nasotemporal and dorsoventral enlargement of the goggled eye were similar to that in the shams, but the axial elongation and the degree of myopia (-9.57 D) were less than observed in sham control eyes. As in the shams, CBF in the goggled eye was reduced to 59% of that in the nongoggled eye.
These results show that although elimination of accommodation and severe reductions in CBF do affect eye growth (the latter more so), they do not prevent form-vision deprivation-induced myopia. Thus, either the mechanism of visual deprivation-induced myopia is different from that in idiopathic human myopia, or CBF levels and accommodation do not play a major role in either.
确定脉络膜神经和睫状神经及其分别控制的脉络膜血流（CBF）和调节 - 瞳孔直径在形觉剥夺性近视中的作用。
研究了三组雏鸡：右眼脉络膜神经切断的雏鸡、右眼睫状神经切断的雏鸡以及接受相同手术准备但未进行神经切断的假手术对照雏鸡。在眼眶手术后，将一个塑料圆顶形眼罩粘贴在所有三组雏鸡的右眼上，2周后，使用激光多普勒血流仪测量CBF。然后使用带状检影法测量屈光状态，摘除眼球后使用游标卡尺测量眼轴、鼻颞侧和背腹侧长度。还对眼球进行称重。
在假手术对照雏鸡中，眼罩遮盖眼在各个维度上均有明显的眼球增大，且出现高度近视（-14.68屈光度），眼罩遮盖眼的CBF为未遮盖眼的66%。在脉络膜神经切断的雏鸡中，眼罩遮盖眼在各个维度上的增大程度较小，与假手术对照相比，眼罩遮盖眼的近视程度（-4.74 D）有所减轻。眼罩遮盖眼的CBF为未遮盖眼的21%。最后，在睫状神经切断的雏鸡中，眼罩遮盖眼的鼻颞侧和背腹侧增大与假手术组相似，但眼轴伸长和近视程度（-9.57 D）低于假手术对照眼。与假手术组一样，眼罩遮盖眼的CBF降至未遮盖眼的59%。
这些结果表明，虽然消除调节和CBF的严重降低确实会影响眼球生长（后者影响更大），但它们并不能预防形觉剥夺性近视。因此，要么视觉剥夺性近视的机制与特发性人类近视不同，要么CBF水平和调节在两者中均不发挥主要作用。
