浅视杯小视盘与前部缺血性视神经病变发病的关系

摘要

目的 观察非动脉炎性前部缺血性视神经病变(NAION)患者视盘视杯形态特征与发病的关系.方法 符合NAION诊断标准,病史≥3个月,水肿消退期的96例NAION患者的96只患眼、96只对侧眼和80只正常对照眼纳入研究.应用德国Carl Zeiss公司Humphrey2000型光相干断层扫描(OCT)检查系统进行"十字交叉"和"环形"扫描,分别测量视盘、视杯水平垂直直径、视杯深度及视盘周围(盘周)视网膜神经纤维层(RNFL)厚度,依OCT视杯深浅形态图像分为4级:Ⅰ级,视杯底部高于盘周神经上皮层前表面水平;Ⅱ级,视杯底部高于盘周神经上皮层面水平;Ⅲ级,视杯底部位于盘周神经上皮层面与脉络膜色素上皮水平之间;Ⅳ级,视杯底部位于脉络膜色素上皮水平连线之下,对视杯分级情况和各组测量数值进行统计分析.随访观察6个月～3年,平均随访观察15个月.结果 患眼、对侧眼、正常对照眼视盘水平扫描直径分别为(1.29±0.19)、(1.32±0.17)、(1.40±0.15)mm,垂直扫描直径分别为(1.52 4±0.14)、(1.49±0.17)、(1.60±0.22)mm.患眼、对侧眼视盘水平扫描直径平均值与正常对照眼视盘水平扫描直径平均值比较,差异有统计学意义(t=4.291,3.315;P<0.05);视盘垂直扫描直径平均值与正常对照眼垂直扫描直径平均值比较,差异有统计学意义(t=2.812,3.654;P<0.05);患眼视盘水平、垂直扫描直径平均值与对侧眼视盘水平、垂直扫描直径平均值比较,差异无统计学意义(t=1.153,1.335;P>0.05).患眼中Ⅰ级视杯者36只眼,占37.50%,Ⅱ～Ⅲ级视杯者52只眼,占54.17%,Ⅳ级视杯者8只眼,占8.33%,Ⅰ～Ⅲ级视杯者共88只眼,占91.67%;对侧眼中Ⅰ级视杯者18只眼,占18.75%,Ⅱ～Ⅲ级视杯者69只眼,占71.88%,Ⅳ级视杯者9只眼,占9.34%,Ⅰ～Ⅲ级视杯者87只眼,占90.66%.依颞侧、上、鼻、下各象限顺序患眼RNFL测量平均值与对侧眼、正常对照眼比较,差异有统计学意义(t=12.862,10.147,15.046,8.180,12.859,9.562,12.174,8.632;P<0.001);对侧眼与正常对照眼各象限RNFL厚度平均值比较,差异无统计学意义(t=1.040,1.576,1.062,1.192;P>0.05).在观察期内,患眼8只眼复发,其视杯为Ⅰ、Ⅱ级形态;对侧眼44只眼发病,占45.8%,相关性分析显示发病率和视杯深度呈负相关(t=-0.757,P=0.000).结论 NAION患跟及对侧眼视杯及视盘明显小于正常人,浅视杯和小视盘的解剖学特点是NAION发病的基础之一.%Objective To observe the relationship between shallow optic cup. small disc and occurrence in patients with non-arteritic anterior ischemic optic neuropathy (NAION). Methods Ninety-six patients(96 diseased eyes) who accorded with the diagnosis criteria for NAION, with duration ≥ three months and optic disc edema in paracmasis were selected. The fellow eyes of 96 NAION patients and 80 normal eyes were selected in our study. The horizontal and vertical disc and cup diameters,optic cup depth,and peripapillary retinal nerve fiber layer (RNFL) thickness were measured by "cross" and "ring" scan of optical coherence tomography (OCT, Humphrey 2000,German Carl Zeiss Company) inspection system. The cup depth were classified four grades by cup shape according to OCT images:Grade Ⅰ,bottom of optic cup above the anterior plane of peripapillary neuroepithelial layer(PNL);Grade Ⅱ ,bottom of optic cup above the plane of PNL; Gr adeⅢ,bottom of optic cup between the plane of PNL and choroidal pigment epithelium; Grade Ⅳ,bottom of optic cup under the plane of choroidal pigment epithelium connection. The grades of optic cup and value in three groups were statistically analyzed. The follow-up ranged from six months to three years. Results The disc diameter in horizontal scanning of diseased eyes, fellow eyes and normal eyes were (1.29±0. 19), (1.32 ± 0. 17), (1.40±0. 15) mm,and diameters in vertical scanning were (1.52± 0.14), (1.49±0.17), (1. 60±0. 22) mm, respectively. Compared the diseased eyes and fellow eyes with normal eyes,the difference were statistically significant in horizontal scanning (t = 4. 291,3. 315; P<0. 05) and in vertical scanning (t=2. 812, 3. 654; P<0. 05). Compared the diseased eyes with fellow eyes, the difference of average diameter were not statistically significant in horizontal and vertical scanning (t=1. 153, 1. 335; P>0. 05). Of the diseased eyes, Grade Ⅰ optic cup in 36 eyes(37. 50), Grade Ⅱ-Ⅲ optic cup in 52 eyes(54. 17%),Grade IV optic cup in eight eyes(8. 33%),and Grade Ⅰ-Ⅲ optic cup in 88 eyes(91. 67%) were found. Of the fellow eyes,Grade I optic cup in 18 eyes(18. 75%),Grade Ⅱ-Ⅲ optic cup in 69 eyes (71. 88%), Grade IV optic cup in nine eyes (9. 34%) ,and Grade Ⅰ-Ⅲ optic cup in 87 eyes (90. 66 %) were found. Compared the average RNFL thickness of diseased eyes with the fellow eyes and normal eyes, the differences were statistically significant in temporal, upper, nasal, lower quadrant (t = 12. 862, 10. 147, 15.046,8. 180,12. 859,9. 562,12. 174, 8. 632; P<0. 001). Compared the average RNFL thickness of the fellow eyes and normal eyes, the differences were not statistically significant in all quadrants (t = 1. 040,1. 576,1. 062,1. 192; P>0. 05). During the follow-up, eight eyes with recurrence which optic cup were Grade I andⅡ in diseased eyes; 44 eyes(45. 8%) occurred NAION. Correlation analysis showed that there was negative correlation between incidence of fellow eye and optic cup depth(r= -0. 757, P = 0.000). Conclusion Optic cup and disk in NAION patients are smaller than that in the normal, the anatomical characteristics of shallow cup and small disc was one of the NAION pathogenesis.