Background/aims The reason for visual impairment in patients with nanophthalmos and posterior microphthalmos is not completely understood. Therefore, this study aims to investigate foveal structure, and the impact of demographic, clinical and imaging parameters on best-corrected visual acuity (BCVA) in these conditions. Methods Sixty-two eyes of 33 patients with nanophthalmos (n=40) or posterior microphthalmos (n=22), and 114 eyes of healthy controls with high-resolution retinal imaging including spectral-domain or swept-source optical coherence tomography images were included in this cross-sectional case–control study. Foveal retinal layer thickness was determined by two independent readers. A mixed-effect model was used to perform structure–function correlations and predict the BCVA based on subject-specific variables. Results Most patients (28/33) had altered foveal structure associated with loss of foveal avascular zone and impaired BCVA. However, widening of outer nuclear layer, lengthening of photoreceptor outer segments, normal distribution of macular pigment and presence of Henle fibres were consistently found. Apart from the presence of choroidal effusion, which had significant impact on BCVA, the features age, refractive error, axial length and retinal layer thickness at the foveal centre explained 61.7% of the variability of BCVA. Conclusion This study demonstrates that choroidal effusion, age, refractive error, axial length and retinal layer thickness are responsible for the majority of interindividual variability of BCVA as well as the morphological foveal heterogeneity in patients with nanophthalmos or posterior microphthalmos. This might give further insights into the physiology of foveal development and the process of emmetropisation, and support clinicians in the assessment of these disease entities. Data are available on reasonable request.

中文翻译：

---

纳米眼和后部小眼的中心凹结构和视觉功能

背景/目的 纳米眼和后部小眼患者视力障碍的原因尚不完全清楚。因此，本研究旨在调查中心凹结构，以及人口统计学、临床和影像学参数对这些条件下最佳矫正视力 (BCVA) 的影响。方法 纳入 33 例纳米眼 (n=40) 或后部小眼 (n=22) 患者的 62 只眼和健康对照组 114 只眼，包括光谱域或扫描源光学相干断层扫描图像在内的高分辨率视网膜成像在这项横断面病例对照研究中。中心凹视网膜层厚度由两个独立的读者确定。混合效应模型用于执行结构 - 功能相关性并根据受试者特定变量预测 BCVA。结果 大多数患者 (28/33) 的中心凹结构发生改变，与中心凹无血管区丢失和 BCVA 受损有关。然而，始终发现外核层增宽、感光器外段延长、黄斑色素正态分布和亨勒纤维的存在。除了脉络膜积液对 BCVA 有显着影响外，中心凹中心的年龄、屈光不正、眼轴长度和视网膜层厚度等特征解释了 BCVA 变异性的 61.7%。结论 本研究表明，脉络膜积液、年龄、屈光不正、眼轴长度和视网膜层厚度是造成 BCVA 个体间差异的主要原因，以及纳米眼或后部小眼患者的中心凹形态异质性。这可能会进一步深入了解中央凹发育的生理学和正视化过程，并支持临床医生评估这些疾病实体。可根据合理要求提供数据。