Optimization of the open-loop liquid crystal adaptive optics retinal imaging system

• Published in: Journal of Biomedical Optics 2012-02, Vol.17 (2), p.026001-026006
• Main Authors: Kong, Ningning, Li, Chao, Xia, Mingliang, Li, Dayu, Qi, Yue, Xuan, Li
• Format: Article
• Language: English
• Subjects: Aberration; Adaptive optics; Channels; Dispersions; Equipment Design; Equipment Failure Analysis; field of view; Humans; Illumination; Image Enhancement - instrumentation; Imaging; liquid crystal spatial light modulator; Liquid crystals; Liquid Crystals - chemistry; Myopia; open-loop; Refractometry - instrumentation; Reproducibility of Results; Retina - anatomy & histology; retinal imaging; Retinoscopes; Sensitivity and Specificity
• ISSN: 1083-3668; 1560-2281
• DOI: 10.1117/1.JBO.17.2.026001

An open-loop adaptive optics (AO) system for retinal imaging was constructed using a liquid crystal spatial light modulator (LC-SLM) as the wavefront compensator. Due to the dispersion of the LC-SLM, there was only one illumination source for both aberration detection and retinal imaging in this system. To increase the field of view (FOV) for retinal imaging, a modified mechanical shutter was integrated into the illumination channel to control the size of the illumination spot on the fundus. The AO loop was operated in a pulsing mode, and the fundus was illuminated twice by two laser impulses in a single AO correction loop. As a result, the FOV for retinal imaging was increased to 1.7-deg without compromising the aberration detection accuracy. The correction precision of the open-loop AO system was evaluated in a closed-loop configuration; the residual error is approximately (root-mean-square, RMS), and the Strehl ratio ranges to 0.7217. Two subjects with differing rates of myopia (-3D and -5D) were tested. High-resolution images of capillaries and photoreceptors were obtained.