SLM-based interferometer for assessing the polychromatic neural transfer function of the eye.

Area of Science:

• Ophthalmology
• Optical Engineering
• Vision Science

Background:

• Accurate measurement of the eye's neural transfer function (NTF) is crucial for understanding visual perception.
• Existing methods for NTF measurement can be complex and sensitive to environmental factors.

Purpose of the Study:

• To present a novel, digitally controlled interferometric instrument for measuring the NTF of the eye.
• To assess the instrument's performance across different lighting conditions and its potential for color vision research.

Main Methods:

• Development of an instrument using a liquid-crystal-on-silicon spatial light modulator (SLM) as a shearing interferometer.
• The SLM generates two interfering wavefronts on the retina with controllable fringe properties.
• A supercontinuum source produces achromatic fringes, enabling testing under polychromatic and monochromatic light (450, 550, 650 nm).

Main Results:

• The instrument successfully measured NTF in six normal subjects under various light conditions.
• NTF in polychromatic light was approximately 20% higher than in monochromatic green and red light, though not statistically significant.
• The digital control system ensures optical simplicity and robustness against vibrations.

Conclusions:

• The developed instrument provides a simple, vibration-resistant method for measuring the eye's NTF.
• Its digital control and achromatic fringe capability make it suitable for non-laboratory use and color vision research.
• The system allows evaluation of contrast sensitivity function without monochromatic or chromatic aberrations.