Chu Chin-hung, Deng Li, Kee Chea-su
School of Optometry, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong Special Administrative Region.
Vision Res. 2012 Feb 15;55:24-31. doi: 10.1016/j.visres.2011.12.011. Epub 2012 Jan 5.
We determined effects of hemiretinal form deprivation (i.e., form-depriving half of the retina) on central refractive development and posterior eye shape in chicks. Seventy-seven White Leghorn chicks were randomly assigned to receive superior (SRD, "Superior Retinal Deprivation" or inferior visual field deprivation, same principle applies for the following abbreviations, n=17), inferior (IRD, n=14), temporal (TRD, n=23) or nasal hemiretinal (NRD, n=23) form deprivation monocularly from day 5 to day 26. Central refractive errors, expressed as interocular difference in spherical equivalent (M), J0 and J45 astigmatic components, were measured using Hartinger refractometer at the beginning and weekly after treatment for 3weeks. At the end of the treatment period, eyes of a subset of birds were enucleated and eye shape profile was photographed along four different meridians. These digital images were later processed to extract axial length (AL), equatorial diameter (ED), and AL/ED. For comparison purposes, the eye shape profile was also acquired from a separate group of birds reared with monocular full-retinal form deprivation (FRD, n=10). The four hemiretinal form deprivations altered central ametropia and posterior eye shape to different degrees. The biggest contrast in M was found between SRD and IRD groups (mean±SE after 3weeks: SRD=-4.14±0.71 D vs. IRD=+1.24±0.36 D; p<0.05), whereas subtle differences in J0 and J45 components were found across the four treatment groups (both p⩽0.03). SRD group also showed significantly higher AL/ED ratio compared to IRD and NRD groups (0.76±0.05 vs. 0.74±0.07 and 0.75±0.04; both p⩽0.03). Furthermore, M was significantly correlated with AL/ED ratio in the treated eyes of hemiretinal treated chicks (r=-0.55, p<0.001). Our results suggest that mechanism regulating central ametropia can be influenced by selectively interrupting the visual experience at different parts of visual field.
我们确定了半侧视网膜形觉剥夺（即剥夺一半视网膜的形觉）对雏鸡中央屈光发育和眼球后部形态的影响。77只白来航雏鸡被随机分配，于第5天至第26天接受单眼上半侧视网膜剥夺（SRD，“上半侧视网膜剥夺”，即剥夺上半视野，以下缩写同理，n = 17）、下半侧视网膜剥夺（IRD，n = 14）、颞侧半侧视网膜剥夺（TRD，n = 23）或鼻侧半侧视网膜剥夺（NRD，n = 23）。使用哈廷格验光仪在治疗开始时及治疗后3周每周测量中央屈光不正，以等效球镜度的眼间差异（M）、J0和J45散光分量表示。在治疗期结束时，摘除一部分雏鸡的眼睛，沿四条不同子午线拍摄眼球形态轮廓照片。这些数字图像随后被处理以提取眼轴长度（AL）、赤道直径（ED）和AL/ED。为作比较，还从另一组单眼全视网膜形觉剥夺（FRD，n = 10）饲养的雏鸡获取眼球形态轮廓。四种半侧视网膜形觉剥夺对中央屈光不正和眼球后部形态有不同程度的改变。在SRD组和IRD组之间发现M的差异最大（3周后均值±标准误：SRD = -4.14±0.71 D，IRD = +1.24±0.36 D；p < 0.05），而在四个治疗组中J0和J45分量存在细微差异（均p⩽0.03）。与IRD组和NRD组相比，SRD组的AL/ED比值也显著更高（0.76±0.05对比0.74±0.07和0.75±0.04；均p⩽0.03）。此外，在半侧视网膜剥夺雏鸡的治疗眼中，M与AL/ED比值显著相关（r = -0.55，p < 0.001）。我们的结果表明，调节中央屈光不正的机制可能受选择性中断视野不同部位视觉经验的影响。
