Volunteers were prospectively recruited and classified by experienced doctors into suspected Demodex blepharitis or healthy controls using slit-lamp evaluation of the eyelid margin and an inquiry about symptoms. Three eyelashes from each eyelid were epilated from participants in each group for microscopic observation and mite counting. Then, swabs from the eyelid margins of each eye were collected after the eyelashes were epilated and stored at -80 °C for future DNA extraction and digital polymerase chain reaction detection. The positive or negative results of both methods were compared for diagnostic accuracy, and the Kappa value was also calculated to evaluate their consistency.
The accuracy of the digital polymerase chain reaction detection was 71.6% and that of the mite counting method was 75%. Their combined accuracy was improved to 77.3%. The Kappa value of the two methods was 0.505, indicating moderate consistency.
Digital polymerase chain reaction detection of Demodex from ocular surface swabs was painless and noninvasive and is a potentially accurate quantitative method available for diagnosing Demodex blepharitis. This method is also complementary to the conventional mite counting method, particularly when a sufficient number of eyelashes cannot be effectively epilated.
■有经验的医生前瞻性招募志愿者,并使用裂隙灯评估眼睑边缘并询问症状,将其分类为疑似蠕形螨眼睑炎或健康对照。每组参与者从每个眼睑脱出三根睫毛,进行显微镜观察和螨计数。然后,睫毛脱毛后,从每只眼睛的眼睑边缘收集拭子,并储存在-80°C,用于将来的DNA提取和数字聚合酶链反应检测。比较两种方法的阳性或阴性结果的诊断准确性,并计算Kappa值以评估其一致性。
■数字聚合酶链反应检测的准确性为71.6%,螨计数方法的准确性为75%。它们的组合精度提高到77.3%。两种方法的Kappa值为0.505,表明中等一致性。
■从眼表拭子中进行蠕形螨的数字聚合酶链反应检测是无痛且无创的,是一种可用于诊断蠕形螨眼睑炎的潜在准确定量方法。这种方法也是对常规螨计数方法的补充,特别是当足够数量的睫毛不能有效地脱毛时。