System to Image the Human Eye Corrects for Chromatic Aberrations


WASHINGTON—Researchers report a new imaging system that cancels the chromatic optical aberrations present in a specific person’s eye, allowing for a more accurate assessment of vision and eye health. By taking pictures of the eye’s smallest light-sensing cells with multiple wavelengths, the system also provides the first objective measurement of longitudinal chromatic aberrations (LCA), which could lead to new insights on their relationship to visual halos, glare and color perception.Writing in Optica, The Optical Society's journal for high-impact research, the researchers, from the University of Washington, Seattle, say the technology can be readily deployed in the clinic, where it could be particularly useful for assessing eye changes associated with aging and can also help inform the design of new multifocal lenses by accounting for chromatic aberrations in the lenses themselves.

For vision research, the technique could advance studies of color blindness and how different people perceive color.

“The previous methods of compensating the eye’s native LCA rely on population average estimates, without individualized correction on a person-by-person basis,” said research team leader, Ramkumar Sabesan. “We demonstrate a modified filter-based Badal optometer that offers the capability to tune LCA across different wavelength bands and for each individual in a customized fashion.”

Researcher Ramkumar Sabesan and a patient test the new imaging system
The researchers report incorporating a new optical assembly into conventional adaptive optics instruments to produce individually tailored high-resolution, multiple-wavelength pictures of the smallest cone photoreceptors in the eye, measuring about 2 microns across.

“Our study establishes a flexible tool to compensate for chromatic aberration in different wavelength bands and in an individualized manner, thus facilitating future investigations into how we see color in our environment, unimpeded by the native chromatic imperfections of the individual,” said Sabesan. “Now equipped with the tools to control chromatic aberration, we plan to conduct studies on normal and deficient color vision.”