The diagnosis of Parkinson disease (PD) is mainly based on clinical symptoms, and there is a lack of objective methods for correct diagnosis. At present, there have been studies on retinal structural changes as a biomark for early diagnosis of PD, but machine learning based on retinal structural changes for predicting early PD has not yet been studied.

To construct a machine learning model based on the characteristics of retinal structural changes, explore its value in early PD diagnosis, and the accuracy of different machine learning algorithms for early PD diagnosis.

From October 2021 to September 2022, 49 PD patients aged 40 to 70 years old (PD group) who attended outpatient clinics and were hospitalized in the department of neurology of Henan Provincial People's Hospital (PD group) and 39 healthy people with matching age and sex (healthy control group) who came to the hospital for physical examination were collected. All study subjects underwent swept-source optical coherence tomography and swept-source optical coherence tomography angiography, the thickness and vessel density of the macular retina were also quantitatively analyzed. The 88 subjects were randomly divided into the 62 training sets and 26 validation set according to the ratio of 7∶3. Variables with significant differences between the PD group and healthy control group were selected as the characteristic variables for inclusion in the machine learning model, and Logistic regression (LR) , K-nearest neighbor algorithm (KNN) , decision tree (DT) , random forest (RF) and extreme gradient boosting (XGboost) models were constructed in the training set. The area under the curve (AUC) , accuracy, sensitivity and specificity of the receiver operating characteristic (ROC) curve were used to evaluate the predictive value of the machine learning model based on retinal structural changes for early PD.

Compared with the healthy control group, the density of the upper outer ring (A6) , the outer temporal outer ring (A7) , the lower outer ring (A8) and the outer nasal ring (A9) of the superficial capillaries in the PD group were reduced, the thickness of the upper inner ring (A2) , the inner temporal inner ring (A3) , the inferior inner ring (A4) , the inner ring of the nasal side (A5) of the retinal layer, A6, A7, A8 and A9, the thickness of A6 of the ganglion cell complex layer, the thickness of A7 of the nerve fiber layer, A2 and A4, A5, A6, A7, A8, A9 became thinner (P<0.05) . The reductions in A2 thickness of the retinal layer (OR=0.781, 95%CI=0.659-0.926) , A3 thickness of the retinal layer (OR=1.190, 95%CI=1.019-1.390) , A2 thickness of the outer retina (OR=0.748, 95%CI=0.603-0.929) , A6 thickness of the outer retina (OR=2.264, 95%CI=1.469-3.490) , A8 thickness of the outer retina (OR=0.723, 95%CI=0.576-0.906) , and A7 thickness of the nerve fiber layer (OR=0.592, 95%CI=0.454-0.773) , and the decrease in A7 density of the superficial capillaries (OR=1.966, 95%CI=1.399-2.765) were independent risk factors for the occurrence of early PD (P<0.05) . The above variables were involved to construct the machine learning model, the results showed that among the five models constructed, the LR model had the highest overall performance, with an AUC of 0.841, while the DT model has the highest accuracy at 0.846.

Machine learning model based on retinal features can accurately predict early PD, among which the DT model has high accuracy for early PD diagnosis.

帕金森病（PD）的诊断主要以临床症状为主，缺乏正确诊断的客观方法。目前已有关于视网膜结构改变作为PD早期诊断的生物标志的研究，但基于视网膜结构改变的机器学习对预测早期PD的研究尚少。

基于视网膜结构改变的特征构建机器学习模型，探索其在早期PD诊断中的预测价值，及探讨不同机器学习算法对PD早期诊断的准确性。

选取2021年10月—2022年9月在河南省人民医院神经内科门诊就诊和住院治疗的年龄40~70岁的PD患者49例（PD组），并选取来医院体检的年龄及性别相匹配的39名健康者（健康对照组）为研究对象。所有研究对象行扫频源光学相关断层扫描和扫频源光学相干断层扫描血流成像检查，并定量分析黄斑区视网膜的厚度和血管密度。将88例受试者按7∶3的比例随机分为训练集62例和验证集26例，选择PD组与健康对照组差异有统计学意义的变量作为纳入机器学习模型的特征变量，并在训练集中分别构建Logistic回归（LR）、K-近邻算法（KNN）、决策树（DT）、随机森林（RF）和极端梯度提升（XGboost）模型。采用受试者工作特征（ROC）曲线下面积（AUC）、准确度、灵敏度和特异度评价基于视网膜改变的机器学习模型对早期PD诊断的预测价值。

与健康对照组相比，PD组患者浅层毛细血管的上方外圈（A6）、颞侧外圈（A7）、下方外圈（A8）以及鼻侧外圈（A9）密度减少，视网膜层的上方内圈（A2）、颞侧内圈（A3）、下方内圈（A4）、鼻侧内圈（A5）、A6~A9厚度，节细胞复合体层的A9厚度，神经纤维层的A7厚度，视网膜外层的A2和A4~A9厚度变薄（P<0.05）。视网膜层A2厚度（OR=0.781，95%CI=0.659~0.926）、视网膜层A3厚度（OR=1.190，95%CI=1.019~1.390）、视网膜外层A2厚度（OR=0.748，95%CI=0.603~0.929）、视网膜外层A6厚度（OR=2.264，95%CI=1.469~3.490）、视网膜外层A8厚度（OR=0.723，95%CI=0.576~0.906）以及神经纤维层A7厚度变薄（OR=0.592，95%CI=0.454~0.773）及浅层毛细血管A7密度减少（OR=1.966，95%CI=1.399~2.765）为早期PD发生的独立危险因素（P<0.05）。将上述变量纳入并构建机器学习模型，结果显示，构建的5个模型中，LR模型整体性能最高，其AUC为0.841，而DT模型的准确度最高，其准确度为0.846。

基于视网膜特征的机器学习模型可准确的预测早期PD，其中，DT模型对早期PD诊断具有较高的准确度。