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

J Biomed Opt. 2012 Feb;17(2):026001. doi: 10.1117/1.JBO.17.2.026001.

Abstract

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 0.0909λ (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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Equipment Design
  • Equipment Failure Analysis
  • Humans
  • Image Enhancement / instrumentation*
  • Liquid Crystals / chemistry*
  • Refractometry / instrumentation*
  • Reproducibility of Results
  • Retina / anatomy & histology*
  • Retinoscopes*
  • Sensitivity and Specificity