Huang Xiaojing, Hargrave Aubrey, Bentley Julie, Dubra Alfredo
Institute of Optics, University of Rochester, Rochester, New York 14620, USA.
Byers Eye Institute, Stanford University, Palo Alto, California 94303, USA.
Biomed Opt Express. 2024 Sep 4;15(10):5674-5690. doi: 10.1364/BOE.536645. eCollection 2024 Oct 1.
The change in ocular wavefront aberrations with visual angle determines the isoplanatic patch, defined as the largest field of view over which diffraction-limited retinal imaging can be achieved. Here, we study how the isoplanatic patch at the foveal center varies across 32 schematic eyes, each individualized with optical biometry estimates of corneal and crystalline lens surface topography, assuming a homogeneous refractive index for the crystalline lens. The foveal isoplanatic patches were calculated using real ray tracing through 2, 4, 6 and 8 mm pupil diameters for wavelengths of 400-1200 nm, simulating five adaptive optics (AO) strategies. Three of these strategies, used in flood illumination, point-scanning, and line-scanning ophthalmoscopes, apply the same wavefront correction across the entire field of view, resulting in almost identical isoplanatic patches. Two time-division multiplexing (TDM) strategies are proposed to increase the isoplanatic patch of AO scanning ophthalmoscopes through field-varying wavefront correction. Results revealed substantial variation in isoplanatic patch size across eyes (40-500%), indicating that the field of view in AO ophthalmoscopes should be adjusted for each eye. The median isoplanatic patch size decreases with increasing pupil diameter, coarsely following a power law. No statistically significant correlations were found between isoplanatic patch size and axial length. The foveal isoplanatic patch increases linearly with wavelength, primarily due to its wavelength-dependent definition (wavefront root-mean-squared, RMS <λ/14), rather than aberration chromatism. Additionally, ray tracing reveals that in strongly ametropic eyes, induced aberrations can result in wavefront RMS errors as large as λ/3 for an 8-mm pupil, with implications for wavefront sensing, open-loop ophthalmic AO, spectacle prescription and refractive surgery.
眼波前像差随视角的变化决定了等晕区，等晕区被定义为能够实现衍射极限视网膜成像的最大视场。在此，我们研究了32只模型眼中央凹中心的等晕区如何变化，每只眼睛都根据角膜和晶状体表面地形的光学生物测量估计进行了个体化设定，假设晶状体的折射率均匀。通过对400 - 1200 nm波长下2、4、6和8 mm瞳孔直径进行实光线追踪来计算中央凹等晕区，模拟了五种自适应光学（AO）策略。其中三种策略用于泛光照明、点扫描和线扫描检眼镜，在整个视场内应用相同的波前校正，从而产生几乎相同的等晕区。提出了两种时分复用（TDM）策略，通过视场变化的波前校正来增加AO扫描检眼镜的等晕区。结果显示，不同眼睛的等晕区大小存在显著差异（40 - 500%），这表明AO检眼镜的视场应针对每只眼睛进行调整。等晕区的中位数大小随瞳孔直径增大而减小，大致遵循幂律。未发现等晕区大小与眼轴长度之间存在统计学上的显著相关性。中央凹等晕区随波长线性增加，主要是由于其与波长相关的定义（波前均方根，RMS <λ/14），而非像差色差。此外，光线追踪显示，在屈光不正程度较高的眼睛中，诱导像差可能导致8 mm瞳孔的波前RMS误差高达λ/3，这对视波前传感、开环眼科AO、眼镜处方和屈光手术具有重要意义。
