对比度视力检测法在斜视手术疗效评价中的应用研究

目的通过对比度视力(CVA)检测，分析斜视手术后患者的双眼视觉空间分辨能力与视觉质量。 方法纳入2018年12月至2019年6月于深圳市眼科医院斜视与小儿眼科行斜视矫正手术的斜视患者42例(84只眼)。其中，男性18例(36只眼)，女性24例(48只眼)；年龄18~48岁，平均年龄(25.8±5.8)岁。分别检测手术前1 d与手术后1周，在100%、25%、10%和5%的4种对比度下，患者的单眼视力、双眼视力与CVA值。采用均数±标准差描述患者的年龄、双眼远近斜视度与CVA值；采用例数和百分比描述不同斜视类型患者所占的百分比与患者术后CVA值的提高率。采用配对t检验比较斜视患者手术前后的CVA值；采用卡方检验比较不同斜视类型与不同程度双眼单视功能受损患者CVA值的提高率；采用配对卡方检验和Kappa一致性检验比较斜视手术后1周，患者双眼单视功能和双眼CVA检查的结果。 结果在100%、25%、10%和5%的4种对比度下，患者手术前后双眼CVA检查结果的差异有统计学意义(t＝3.655，2.086，2.216，3.699；P<0.05)。手术前后，在100%及25%对比度下，主导眼CVA检查结果的差异有统计学意义(t＝2.742，2.400；P<0.05)；在10%及5%对比度下，主导眼CVA检查结果的差异无统计学意义(t＝2.021，1.773；P>0.05)。在100%、25%、10%和5%对比度下，术后1周与术前相比，主导眼视力降低的患者分别为5例(5只眼)，占11.90%；8例(8只眼)，占19.04%；11例(11只眼)，占26.19%；13例(13只眼)占30.95%。术后1周与术前相比，患者主斜眼CVA检查结果的差异无统计学意义(t＝0.415，0.471，0.659，0.639；P>0.05)。共同性斜视患者中，术后双眼CVA值提高的有24例(48只眼)，占80.00%；非共同性斜视患者中，术后双眼CVA值提高的有5例(10只眼)，占41.67%。外斜视患者中，术后双眼CVA值提高的有23例(46只眼)，占74.19%；内斜视患者中，术后双眼CVA值提高的有4例(8只眼)，占36.36%。共同性斜视与非共同性斜视患者、外斜视与内斜视患者、术前同视机Ⅱ级功能(融合功能)存在与术前同视机Ⅱ级功能(融合功能)受损的患者相比，术后CVA值的提高率更高，且三组患者CVA值提高率的差异有统计学意义(χ² ＝4.60，5.52，5.35；P<0.05)。术后1周，患者双眼CVA值的提高率为69.0%，患者双眼单视功能的提高率为50.0%。两组提高率的比较，差异有统计学意义(χ²＝4.08，P<0.05)。 结论CVA检测法是一种敏感的视功能检查方法。斜视手术后，患者在各对比度下的双眼CVA值均有所改善，主导眼在中高对比度下的视觉空间分辨能力提高。通过CVA检测，可为斜视手术后患者双眼视功能的恢复提供预见性。

Contrast visual acuity change analysis before and after surgery for strabismus

ObjectiveContrast visual acuity (CVA) was used to analyze the binocular visual spatial resolution and visual perception quality after strabismus surgery. MethodsConsecutive patients with strabismus 42 cases (84 eyes) who underwent surgery in Shenzhen Eye Hospital from December 2018 to June 2019. Among of them, there were 18 males (36 eyes) and 24 females (48 eyes); age 18 to 48 years-old with an average age of (25.8±5.8) years-old. The monocular and binocular visual acuity of the patients was measured at 4 contrast levels (100%, 25%, 10%, 5%) , 1 day before and 1 week after surgery. The age, neardistant squint and CVA of the patients were described by mean±standard deviation. The percentage of patients with different types of strabismus and the rate of postoperative CVA improvement were described by cases and percentages. The paired t-test was used to compare the CVA of strabismus patients before and after operation and the chi-square test was used to compare the increase rate of CVA in patients with different strabismus types and different degrees of impaired binocular monocular function. The paired chi-square test and Kappa consistency test were used to compare the results of binocular monocular function test and binocular CVA test 1 week after strabismus surgery. LogMAR contrast visual acuity and reaction times were detected at 4 contrast levels (100%, 25%, 10%, 5%) with standard high background before and 1 week after strabismus surgery. ResultsThe postoperative CVA on binoculus at 4 contrast levels (100%, 25%, 10%, 5%) were higher than the preoperative CVA , and there was statistically significant difference between them (t=3.655, 2.086, 2.216, 3.699; P<0.05). The postoperative CVA in dominant eye at 100% and 25% contrast were higher than the preoperative CVA , and there was were statistically significant difference between them (t=2.742, 2.400; P<0.05), but there were no significant differences between them (t=2.021, 1.773; P>0.05) at 10% and 5% contrast levels. The patients with postoperative CVA in dominant eye had 5 cases (5 eyes), accouting for 11.90%; 8 cases (8 eyes), accouting for 19.04%; 11 cases (11 eyes), accouting for 26.19%; 13 cases (13 eyes), accouting for 30.95% were lower compared with the preoperative CVA at 4 contrast levels (100%, 25%, 10%, 5%). When the postoperative CVA in deviated eye at 4 contrast levels (100%, 25%, 10%, 5%) were compared with the preoperative CVA, there were no significant differences among them (t=0.415, 0.471, 0.659, 0.639; P>0.05). The patients with the increase of postoperative CVA on binoculus had 24 cases (48 eyes), accouting for 80.00%; 5 cases (10 eyes), accouting for 41.67%; 23 cases (46 eyes), accouting for 74.19% and 4 cases (8 eyes), accouting for 36.36% among the patients with concomitant strabismus, non-concomitant strabismus, exotropia and esotropia. The increase rate of the postoperative CVA were higher compared between non-concomitant strabismus and concomitant strabismus; between exotropia and esotropia; between grade Ⅱ binocular function before operation and their deficient function, and there were statistically significant differences among them(χ²=4.60, 5.52, 5.35; P<0.05). The increase rate of the postoperative CVA accouting for 69.0% was higher than binocular vision accouting for 50.0% examined with a synoptophore at 1 week after surgery; and there were statistically significant differences between them (χ²=4.08, P<0.05). ConclusionsCVA was a sensitive detection method for visual function. Strabismus surgery could improve the contrast sensitive visual quality on binoculus and dominant eye at the medium and high frequencies. The close relationship suggests that the detection of CVA may provide foresight for the recovery of binocular function after strabismus surgery.