Adaptive optics visual simulator.

PURPOSE To develop a prototype instrument that uses adaptive optics to introduce virtually any desired aberration profile in a subject's eye. At the same time, the instrument could be used to evaluate the subject's spatial vision for each controlled aberration profile. This "aberration testing station" or "visual simulator" allows us to study the relationship between specific aberrations and visual quality. METHODS The apparatus uses infrared light to measure the wavefront aberration of the system plus the eye with a Hartmann-Shack wavefront sensor. Defocus is added (or removed) with a computer-controlled, motorized optometer, while higher order aberrations are introduced by a 37-channel membrane deformable mirror. A parallel viewing channel is used for visual testing with the instrument. Visual acuity, contrast sensitivity, and other visual tests are performed under normal viewing for each desired aberration profile. RESULTS The range of defocus that can be added is nearly unlimited, while the maximum amount of other aberration modes is restricted to approximately 0.5 microm, depending on mode. Pure modes or any selected combination of modes can be produced with high repeatability and precision (usually better than 0.05 microm), and the system works for pupil diameters up to 6 mm (with a natural pupil). CONCLUSIONS The adaptive optics visual simulator is a powerful, non-invasive tool to evaluate how aberrations affect vision. In addition, it can be used for the interactive design and testing of new ophthalmic devices, and for the simulation of visual outcomes in customized refractive surgery.