FIAT: A Device for Objective, Optical Measures of Accommodation in Phakic and Pseudophakic Eyes

PURPOSE: To present FIAT, a novel optical instrument and analysis package that is designed to elicit and optically record accommodation in human eyes. METHODS: FIAT employs a Shack-Hartmann wavefront sensor and a retro-illumination pupil camera that records from a single eye at video rates. It is effective at eliciting accommodation by offering the subject a full-field binocular view of an alternating distant target and a near-eye display. FIAT analysis software computes wave aberrations for each video frame over full- or subpupil sizes and computes accommodative dynamics and accommodative range. RESULTS: The system is validated by showing accurate refraction measurements in model eyes and human eyes with trial lenses. Robust accommodative responses are shown for young eyes, and a lack of accommodative response is shown for a known presbyopes. Accommodative stimulus–response curves from five phakic subjects over a range of ages show expected results. Results from two individuals with monofocal intraocular lenses are shown. CONCLUSIONS: FIAT is an effective instrument for making accurate, objective measures of accommodation in phakic and pseudophakic eyes. TRANSLATIONAL RELEVANCE: We present a device that can play an important role in the development and testing of accommodating intraocular lenses.