TOPIC OCT is a noninvasive tool to measure specific retinal layers in the eye. The relationship of retinal spectral-domain (SD) OCT measurements with Alzheimer's disease (AD) and mild cognitive impairment (MCI) remains unclear. Hence, we conducted a systematic review and meta-analysis to examine the SD OCT measurements in AD and MCI. CLINICAL RELEVANCE Current methods of diagnosing early AD are expensive and invasive. Retinal measurements of SD OCT, which are noninvasive, technically simple, and inexpensive, are potential biomarkers of AD. METHODS We conducted a literature search in PubMed and Excerpta Medica Database to identify studies published before December 31, 2017, that assessed the associations between AD, MCI, and measurements of SD OCT: ganglion cell-inner plexiform layer (GC-IPL), ganglion cell complex (GCC), macular volume, and choroidal thickness, in addition to retinal nerve fiber layer (RNFL) and macular thickness. We used a random-effects model to examine these relationships. We also conducted meta-regression and assessed heterogeneity, publication bias, and study quality. RESULTS We identified 30 eligible studies, involving 1257 AD patients, 305 MCI patients, and 1460 controls, all of which were cross-sectional studies. In terms of the macular structure, AD patients showed significant differences in GC-IPL thickness (standardized mean difference [SMD], -0.46; 95% confidence interval [CI], -0.80 to -0.11; I2 = 71%), GCC thickness (SMD, -0.84; 95% CI, -1.10 to -0.57; I2 = 0%), macular volume (SMD, -0.58; 95% CI, -1.03 to -0.14; I2 = 80%), and macular thickness of all inner and outer sectors (SMD range, -0.52 to -0.74; all P < 0.001) when compared with controls. Peripapillary RNFL thickness (SMD, -0.67; 95% CI, -0.95 to -0.38; I2 = 89%) and choroidal thickness (SMD range, -0.88 to -1.03; all P < 0.001) also were thinner in AD patients. CONCLUSIONS Our results confirmed the associations between retinal measurements of SD OCT and AD, highlighting the potential usefulness of SD OCT measurements as biomarkers of AD.

中文翻译：

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阿尔茨海默氏病的光谱域OCT测量：系统评价和荟萃分析。

TOPIC OCT是一种非侵入性工具，可以测量眼睛中特定的视网膜层。视网膜光谱域（SD）OCT测量与阿尔茨海默氏病（AD）和轻度认知障碍（MCI）的关系尚不清楚。因此，我们进行了系统的综述和荟萃分析，以检查AD和MCI中的SD OCT测量值。临床相关性当前诊断早期AD的方法昂贵且具有侵入性。SD OCT的视网膜测量无创，技术简单且价格便宜，是AD的潜在生物标记。方法我们在PubMed和Excerpta Medica数据库中进行了文献检索，以鉴定2017年12月31日之前发表的研究，该研究评估了AD，MCI和SD OCT的测量之间的关联：神经节细胞内丛状层（GC-IPL），神经节细胞复合物（GCC），黄斑体积，脉络膜厚度，以及视网膜神经纤维层（RNFL）和黄斑厚度。我们使用随机效应模型来检查这些关系。我们还进行了元回归分析，并评估了异质性，发表偏见和研究质量。结果我们确定了30项合格研究，涉及1257例AD患者，305例MCI患者和1460例对照，所有这些均为横断面研究。就黄斑结构而言，AD患者在GC-IPL厚度方面存在显着差异（标准平均差异[SMD]，-0.46； 95％置信区间[CI]，-0.80至-0.11； I2 = 71％），GCC厚度（SMD，-0.84; 95％CI，-1.10至-0.57; I2 = 0％），黄斑体积（SMD，-0.58; 95％CI，-1.03至-0.14; I2 = 80％），黄斑厚度所有内部和外部扇区（SMD范围为-0.52至-0.74;所有P <0。001）。AD患者的围乳突RNFL厚度（SMD，-0.67； 95％CI，-0.95至-0.38； I2 = 89％）和脉络膜厚度（SMD范围，-0.88至-1.03；所有P <0.001）也较薄。结论我们的结果证实了SD OCT的视网膜测量和AD之间的关联，突出了SD OCT测量作为AD的生物标志物的潜在实用性。