Sredar Nripun, Fagbemi Oladipo E, Dubra Alfredo
Byers Eye Institute, Stanford University, Palo Alto, CA, USA.
Medical College of Wisconsin, WI, USA.
Transl Vis Sci Technol. 2018 Apr 4;7(2):17. doi: 10.1167/tvst.7.2.17. eCollection 2018 Apr.
To demonstrate the viability of improving transverse image resolution in reflectance scanning adaptive optics ophthalmoscopy using sub-Airy disk confocal detection.
The foveal cone mosaic was imaged in five human subjects free of known eye disease using two custom adaptive optics scanning light ophthalmoscopes (AOSLOs) in reflectance with 7.75 and 4.30 mm pupil diameters. Confocal pinholes of 0.5, 0.6, 0.8, and 1.0 Airy disk diameters (ADDs) were used in a retinal conjugate plane before the light detector. Average cone photoreceptor intensity profile width and power spectrum were calculated for the resulting images. Detected energy using a model eye was recorded for each pinhole size.
The cone photoreceptor mosaic is better resolved with decreasing confocal pinhole size, with the high spatial frequency content of the images enhanced in both the large- and small-pupil AOSLOs. The average cone intensity profile width was reduced by ∼15% with the use of a 0.5 ADD pinhole when compared to a 1.0 ADD, with an accompanying reduction in signal greater than a factor of four.
The use of sub-Airy disk confocal pinhole detection without increasing retinal light exposure results in a substantial improvement in image resolution at the cost of larger than predicted signal reduction.
Improvement in transverse resolution using sub-Airy disk confocal detection is a practical and low-cost approach that is applicable to all point- and line-scanning ophthalmoscopes, including optical coherence tomographers.
证明在反射扫描自适应光学检眼镜中使用亚艾里斑共焦检测提高横向图像分辨率的可行性。
使用两台定制的自适应光学扫描激光检眼镜（AOSLO），在反射模式下对五名无已知眼部疾病的人类受试者的中央凹视锥细胞镶嵌进行成像，瞳孔直径分别为7.75和4.30毫米。在光探测器之前的视网膜共轭平面中使用直径为0.5、0.6、0.8和1.0个艾里斑直径（ADD）的共焦针孔。计算所得图像的平均视锥光感受器强度分布宽度和功率谱。记录每个针孔尺寸下使用模型眼检测到的能量。
随着共焦针孔尺寸减小，视锥光感受器镶嵌的分辨率更高，在大瞳孔和小瞳孔AOSLO中图像的高空间频率成分均增强。与1.0 ADD针孔相比，使用0.5 ADD针孔时平均视锥强度分布宽度降低了约15%，同时信号降低超过四倍。
使用亚艾里斑共焦针孔检测，在不增加视网膜光暴露的情况下，可大幅提高图像分辨率，但代价是信号降低幅度大于预期。
使用亚艾里斑共焦检测提高横向分辨率是一种实用且低成本的方法，适用于所有点扫描和线扫描检眼镜，包括光学相干断层扫描仪。
