Domdei Niklas, Linden Michael, Reiniger Jenny L, Holz Frank G, Harmening Wolf M
Department of Ophthalmology, University of Bonn, Germany.
Biomed Opt Express. 2019 Jul 18;10(8):4126-4141. doi: 10.1364/BOE.10.004126. eCollection 2019 Aug 1.
Multi-wavelength ophthalmic imaging and stimulation of photoreceptor cells require consideration of chromatic dispersion of the eye, manifesting in longitudinal and transverse chromatic aberrations. Contemporary image-based techniques to measure and correct transverse chromatic aberration (TCA) and the resulting transverse chromatic offset (TCO) in an adaptive optics retinal imaging system are precise but lack compensation of small but significant shifts in eye position occurring during testing. Here, we present a method that requires only a single measurement of TCO during controlled movements of the eye to map retinal chromatic image shifts to the image space of a pupil camera. After such calibration, TCO can be compensated by continuously monitoring eye position during experimentation and by interpolating correction vectors from a linear fit to the calibration data. The average change rate of TCO per head shift and the correlation between Kappa and the individual foveal TCA are close to the expectations based on a chromatic eye model. Our solution enables continuous compensation of TCO with high spatial precision and avoids high light intensities required for re-measuring TCO after eye position changes, which is necessary for foveal cone-targeted psychophysical experimentation.
多波长眼科成像和光感受器细胞刺激需要考虑眼睛的色散，这表现为纵向和横向色差。在自适应光学视网膜成像系统中，当代基于图像的测量和校正横向色差（TCA）以及由此产生的横向色差偏移（TCO）的技术很精确，但在测试过程中缺乏对眼睛位置微小但显著变化的补偿。在这里，我们提出一种方法，该方法仅需在眼睛的受控运动期间对TCO进行一次测量，就可以将视网膜色差图像偏移映射到瞳孔相机的图像空间。经过这样的校准后，通过在实验期间连续监测眼睛位置，并从校准数据的线性拟合中插值校正向量，就可以补偿TCO。每次头部移动时TCO的平均变化率以及卡帕值与个体中央凹TCA之间的相关性接近基于色差眼模型的预期。我们的解决方案能够以高空间精度连续补偿TCO，并且避免了在眼睛位置变化后重新测量TCO所需的高光强度，这对于以中央凹视锥细胞为目标的心理物理学实验是必要的。
