Reinstein Dan Z, Gobbe Marine, Archer Timothy J, Carp Glenn I
J Refract Surg. 2016 Jun 1;32(6):364-71. doi: 10.3928/1081597X-20160428-05.
Case series report of normal-appearing eyes after hyperopic LASIK exhibiting diurnal shift in refractive error found to correlate with diurnal shifts in epithelial thickness profile.
Patients complaining of diurnal shift in vision during the course of the day with more hyperopia on waking and decreasing hyperopia in the evening in the absence of abnormal epithelial or slit-lamp findings were examined. Diurnal concomitant measurement of refraction, topography, and Artemis very high-frequency digital ultrasound scanning (VHFDU) (ArcScan Inc., Morrison, CO) epithelial thickness profile mapping was undertaken throughout the day. A full review of the clinical database revealed 8 eyes of 5 patients with such symptoms. The authors report the findings in 6 eyes of 4 patients with such symptoms.
Excimer ablation was performed with standard aspheric profiles of 7-mm (4 eyes) and 6.5-mm (2 eyes) optical zone, centered on the coaxially fixating nascent corneal vertex. The total spherical equivalent laser data entry (primary plus re-treatments) was between +3.22 and +8.33 diopters (D). Mean postoperative keratometry was between 41.2 and 48.35 D. One eye treated for spherical equivalent of +4.25 D spontaneously resolved and the remaining 5 eyes possessed increasing central epithelial thickness from morning to afternoon correlated with increased central corneal power and reduced hyperopia. This complication represented 0.3% of all hyperopic eyes treated within a similar refractive range.
This phenomenon of diurnal refractive instability in the absence of clinical slit-lamp findings has not been reported previously. The cause has been identified as being due to idiosyncratic diurnal epithelial thickness profile changes. Further study into predictors for this complication and reversal is underway. [J Refract Surg. 2016;32(6):364-371.].
病例系列报告显示，远视性准分子激光原位角膜磨镶术（LASIK）后外观正常的眼睛出现屈光不正的日变化，且发现其与上皮厚度分布的日变化相关。
对那些在白天视力出现日变化、晨起时远视度数更高而傍晚时远视度数降低且上皮或裂隙灯检查无异常的患者进行检查。全天同步测量屈光、地形图以及使用阿耳忒弥斯甚高频数字超声扫描（VHFDU）（ArcScan公司，科罗拉多州莫里森）进行上皮厚度分布绘图。对临床数据库进行全面回顾后发现，5例患者的8只眼睛有此类症状。作者报告了4例有此类症状患者的6只眼睛的检查结果。
使用标准非球面轮廓对7毫米（4只眼）和6.5毫米（2只眼）光学区进行准分子激光消融，以同轴固定的新生角膜顶点为中心。总的等效球镜激光数据输入量（初次治疗加再次治疗）在+3.22至+8.33屈光度（D）之间。术后平均角膜曲率计读数在41.2至48.35 D之间。一只等效球镜为+4.25 D的眼睛自发恢复，其余5只眼睛从早晨到下午中央上皮厚度增加，这与中央角膜屈光力增加和远视度数降低相关。在相似屈光范围内接受治疗的所有远视眼中，这种并发症占0.3%。
此前尚未报道过在无临床裂隙灯检查异常情况下出现的日屈光不稳定现象。已确定其原因是特有的日上皮厚度分布变化。目前正在对该并发症的预测因素及逆转情况进行进一步研究。[《屈光手术杂志》。2016年；32(6):364 - 371。]
