近视眼视网膜神经纤维层厚度光学相干断层扫描特点

Characteristics of optical coherence tomography on thickness of retinal nerve fiber layer in myopia

目的:探讨人视网膜神经纤维层(retinal nerve fiber layer,RNFL)厚度随近视眼屈光度及眼轴变化而变化的特点。方法:将近视眼60例108眼分为低、中、高度近视组和正常对照组25例32眼,应用光学相干断层扫描仪(OCT)进行以视盘为中心,直径3.46mm圆周的RNFL厚度测量,研究近视眼平均RNFL厚度与屈光度及眼轴长度的相关性,并计算各组平均RNFL厚度及上、下、鼻、颞4个象限的RNFL厚度,分别比较各近视组与正常组RNFL的差别。结果:近视眼平均RNFL厚度与屈光度呈负相关(r=-0.535,P<0.05),与眼轴成负相关(r=-0.693,P<0.01)。分区分析低度近视组、中度近视组、高度近视组平均RNFL厚度变薄与正常对照组相比有显著统计学差异(P<0.01),近视眼各象限RNFL厚度最早变薄的是鼻侧象限,低度近视组即与正常人有统计学差异(P<0.05),高度近视组上、下、鼻象限RNFL厚度均明显变薄(P<0.01)与正常人相比有显著统计学差异,颞侧象限RNFL反而增厚,但与正常人无统计学差异(P>0.05)。结论:近视眼视网膜神经纤维层厚度随眼轴长度及眼屈光度的增加而减少,分区分析上、下、鼻象限变化与平均相一致,而颞侧增厚,这可能是近视眼RNFL的特点,这些特点对临床疾病的诊断具有指导意义,特别是出现异常数值时,要考虑屈光度及眼轴的影响,综合评价临床意义。

AIM. To study the characteristics and clinical significance of retinal nerve fiber layer （RNFL） thickness along with increase of myopia degree and axial length. METHODS, According to the myopia degree, 140 eyes were divided into four groups as normal, slight, medium and high myopic group. Optical coherence tomography （OCT） was used to measure the RNFL thickness. Each eye was performed circular scans around the optic nerve with a circle size of 3.46 mm. The correlation between the thickness of the mean RNFL and refraction, axial length were calculated. The mean and different quadrants RNFL thickness in different groups was analyzed. RESULTS： There was significant inverse linear correlation between the thickness of the mean RNFL and refraction, and also between the thickness of the mean RNFL and axial length. Compared with normal groups, the mean RNFL thickness values in the slight, medium and high myopic groups were thinner. The change occurred first in nasal quadrant. RNFL thickness values in high myopic groups were significantly thinner in nasal, inferior and superior quadrant. Temporal quadrant was thicker, but had no significance compared with the normal group. CONCULSION： The mean RNFL thickness in myopia groups decreases with axial length and refraction. Apart from temporal quadrant, the thickness of RNFL in other quadrants decrease with axial length. The thickness in temporal RNFL is thicker. The result maybe shows characteristics of RNFL thickness in myopia groups, which is of instructive significance to guide the diagnosis of disease. Effect of axial length of globe on RNFL should be concerned for a clinical diagnosis.