Du Xianli, Han Yanmin, Chen Min
Qingdao Eye Hospital, Shandong Eye Institute, Shandong Academy of Medical Sciences, Qingdao 266071, China.
Qingdao Eye Hospital, Shandong Eye Institute, Shandong Academy of Medical Sciences, Qingdao 266071, China. Email:
Zhonghua Yan Ke Za Zhi. 2015 Jan;51(1):32-8.
To determine the changes of objective optical quality after orthokeratology.
Prospective, self-controlled study. Optical quality, including objective scatter index (OSI), modulation transfer function (MTF) cutoff frequency, contrast visual acuity (CVA) and objective tear film quality, was assessed with the OQAS II instrument before and 1 week, 1 month, and 3 months after orthokeratology. Parameters of corneal astigmatism and e value from topography were also assessed. The data was analyzed using one-way ANOVA.
Cylinder refraction was (-0.39 ± 0.39)D, (-0.65 ± 0.57)D, (-0.79 ± 0.56)D, and (-0.81 ± 0.53) D, respectively, at the four timepoints, and there was a statistically significant difference between before and after therapy (P < 0.05). Uncorrected visual acuity was 3.97 ± 0.51, 4.95 ± 0.12, 5.00 ± 0.06, and 5.00 ± 0.05, respectively. The e value was 0.37 ± 0.24, -0.23 ± 0.42, -0.29 ± 0.39, and -0.30 ± 0.37, respectively. The negative values after therapy were significantly different from the value before therapy (P < 0.01). The corneal astigmatism in 3 mm diameter was (1.27 ± 0.75) D, (1.06 ± 0.69) D, (1.11 ± 0.68) D , and (1.15 ± 0.67) D, respectively. There was no significant difference in astigmatism between before and after therapy (P ≥ 0.05). After therapy, the OSI increased from 0.59 ± 0.47 before therapy to 0.99 ± 0.66 at 1 week, 1.47 ± 1.17 at 1 month, and 1.49 ± 1.03 at 3 months. The difference between pre- and post-therapy OSI values was statistically significant (P < 0.05). The MTF cutoff frequency decreased from (36.6 ± 12.0) cpd before therapy to (34.2 ± 8.9) cpd at 1 week, (27.9 ± 12.6) cpd at 1 month, and (27.7 ± 11.6) cpd at 3 months after therapy. The difference in MTF cutoff frequency between before and 1 month after therapy was statistically significant (P < 0.05). The 100% CVA, 20% CVA, and 9% CVA all declined after therapy, but there was no statistically significant difference between before and after therapy. The OSI of tear film quality was 1.27 ± 1.12, 2.09 ± 1.67, 2.07 ± 1.12, and 2.10 ± 1.33, respectively, and the difference was statistically significant between before and after therapy (P < 0.05).
After 3 months of orthokeratology, the corneal central astigmatism remained, and the e value became negative, while OSI increased, and MTF cutoff frequency and tear film quality declined. The alteration was more and more obvious along with the therapy within 1 month, and was not significant within the following month. After short-term corneal reshaping, the ocular optical quality declined in some degree, but the loss was acceptable.
确定角膜塑形术后客观光学质量的变化。
前瞻性、自身对照研究。使用OQAS II仪器在角膜塑形术前、术后1周、1个月和3个月评估光学质量，包括客观散射指数（OSI）、调制传递函数（MTF）截止频率、对比敏感度视力（CVA）和客观泪膜质量。还评估了角膜散光参数和角膜地形图的e值。数据采用单因素方差分析。
四个时间点的柱镜屈光度分别为（-0.39±0.39）D、（-0.65±0.57）D、（-0.79±0.56）D和（-0.81±0.53）D，治疗前后差异有统计学意义（P<0.05）。裸眼视力分别为3.97±0.51、4.95±0.12、5.00±0.06和5.00±0.05。e值分别为0.37±0.24、-0.23±0.42、-0.29±0.39和-0.30±0.37。治疗后负值与治疗前值差异有统计学意义（P<0.01）。3mm直径的角膜散光分别为（1.27±0.75）D、（1.06±0.69）D、（1.11±0.68）D和（1.15±0.67）D。治疗前后散光无显著差异（P≥0.05）。治疗后，OSI从治疗前的0.59±0.47增加到1周时的0.99±0.66、1个月时的1.47±1.17和3个月时的1.49±1.03。治疗前后OSI值差异有统计学意义（P<0.05）。MTF截止频率从治疗前的（36.6±12.0）cpd降至治疗后1周时的（34.2±8.9）cpd、1个月时的（27.9±12.6）cpd和3个月时的（27.7±11.6）cpd。治疗前与治疗后1个月MTF截止频率差异有统计学意义（P<0.05）。治疗后100%CVA、20%CVA和9%CVA均下降，但治疗前后差异无统计学意义。泪膜质量的OSI分别为1.27±1.12、2.09±1.67、2.07±1.12和2.10±1.33，治疗前后差异有统计学意义（P<0.05）。
角膜塑形术后3个月，角膜中央散光仍存在，e值变为负值，而OSI增加，MTF截止频率和泪膜质量下降。在1个月内随着治疗变化越来越明显，在接下来的1个月内不明显。短期角膜重塑后，眼的光学质量有一定程度下降，但这种损失是可以接受的。
