Effects of accelerated and conventional corneal cross-linking (CXL) on corneal density

This dataset consists of a single SPSS .sav file containing corneal density data for patients with progressive Keratoconus KCN treated by collagen cross-linking (CXL). Patients are divided into two groups of 23 based on treatment type: accelerated and conventional corneal cross-linking (CXL).<br>Variables provided:<br>Patient <b>treatment group</b>, <b>gender </b>and <b>age</b>.<b>Eye: OS</b> (oculus sinister) - left eye, <b>OD</b> (oculus dextrus) - right eye<br>The following variables give corneal density in gray scale units (GSU). Where each has the prefix 'p' in the spreadsheet, this indicates a post-treatment measurement:<br><br><b>ANT:</b> anterior layer<b>CL:</b> middle layer<br><b>POST:</b> posterior layer<b>S0_2MM: </b>0-2 mm zone<b>S2_6MM:</b> 2-6 mm zone<b>S6_10MM:</b> 6-10 mm zone<b>S10_12MM: </b> 10-12 mm zone<b>TOT:</b> Total<br><b>Background of study methods:</b><br>Pentacam densitometry and corneal mapping were performed before and six months following the randomly assigned intervention. Corneal density was measured over different zones and layers of the cornea by two independent ophthalmologists. Total corneal density was calculated. The patients were followed up for the occurrence of procedure related and unrelated complication one week, one month and a final visit around 6 months (180 ± 10 days) after the procedure, during which the corneal density was remeasured and recorded.<br>

本数据集包含单个SPSS格式的.sav文件，收录了接受胶原交联术（Collagen Cross-linking, CXL）治疗的进展性圆锥角膜（Keratoconus, KCN）患者的角膜密度数据。根据治疗类型将患者分为两组，每组各23例，分别为加速型角膜交联术组与传统型角膜交联术组。
提供的变量如下：
患者的**治疗分组**、**性别**与**年龄**；**眼别**：OS（oculus sinister，左眼）、OD（oculus dextrus，右眼）。
下述变量以灰度单位（Gray Scale Unit, GSU）表示角膜密度，电子表格中变量名前缀为“p”的代表治疗后测量值：
- **ANT**：前层
- **CL**：中层
- **POST**：后层
- **S0_2MM**：0-2mm区域
- **S2_6MM**：2-6mm区域
- **S6_10MM**：6-10mm区域
- **S10_12MM**：10-12mm区域
- **TOT**：总角膜密度

研究方法背景说明：
本研究采用随机分配的干预方案，所有患者在术前及术后6个月均接受Pentacam角膜密度测量及角膜地形图检查。由2名独立的眼科医师对角膜不同区域与层次的密度进行测量，并计算总角膜密度。术后分别于1周、1个月及末次随访（约6个月，即180±10天）时对患者进行随访，记录手术相关及非相关并发症的发生情况，并再次测量、记录角膜密度。