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Purpose: We describe new phenomenological illumination-dependent static models of the accommodation deficiency for patients with presbyopia. Such models are suitable for vision restoration with adaptive-optics accommodating eyeglasses and contact lenses. Methods: Data from fifteen participants over the age of 45 and diagnosed with presbyopia was collected. Participants were asked to wear a pair of mechanically-tunable eyeglasses and clearly identify the optotypes corresponding to the LogMAR 0.0 line on Early Treatment of Diabetic Retinopathy Study (ETDRS) charts, by suitably adjusting the optical powers of the lenses on these tunable eyeglasses for each measurement. Seven ETDRS charts, placed at distances from the patients varying from 4 m through 30 cm, were used under three chart illumination levels (75 lx, 500 lx and 800 lx). The optical power of the lenses in the patient-adjusted tunable eyeglasses was subsequently measured using a Shack-Hartman wavefront sensor for each chart, which provided the accommodation deficiency data of the participants. Results: The measured accommodation deficiency data from 15 presbyopes was curve-fitted to a model for each patient. The calculated root-mean-square error values for the fitted models ranged between 0.09 D - 0.67 D over a 3.08 D accommodation stimulus range. Conclusions: The data shows that while accommodation deficiency in humans is a function of the stimulus, it is also strongly dependent on the object illumination and age of the patients. The models adequately describe the relation between static accommodation deficiency, accommodation stimulus and object illumination.

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We present the design, fabrication, and response of a polymer-based Laterally Amplified Chemo-Mechanical (LACM) humidity sensor based on mechanical leveraging and parametric amplification. The device consists of a sense cantilever asymmetrically patterned with a polymer and flanked by two stationary electrodes on the sides. When exposed to a humidity change, the polymer swells after absorbing the analyte and causes the central cantilever to bend laterally towards one side, causing a change in the measured capacitance. The device features an intrinsic gain due to parametric amplification resulting in an enhanced signal-to-noise ratio (SNR). Eleven-fold magnification in sensor response was observed via voltage biasing of the side electrodes without the use of conventional electronic amplifiers. The sensor showed a repeatable and recoverable capacitance change of 11% when exposed to a change in relative humidity from 25–85%. The dynamic characterization of the device also revealed a response time of ~1 s and demonstrated a competitive response with respect to a commercially available reference chip.

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Using high-performance LC (E7) filled microfabricated refractive Fresnel chambers, we experimentally demonstrate a thin low-profile adaptive optical system with high analog tunability (2.1 D) that can be integrated with an adaptive contact-lens system.

Presbyopia, an age-related ocular disorder, is characterized by the loss in the accommodative abilities of the human ocular system and afflicts more than 1.8 billion people world-wide. Conventional methods of correcting presbyopia fragment the field of vision, inherently resulting in significant vision impairment. We demonstrate the development, assembly and evaluation of autofocusing eyeglasses for restoration of accommodation without vision field loss. The adaptive optics eyeglasses consist of two variable-focus piezoelectric liquid lenses, a time-of-flight range sensor and low-power, dual microprocessor control electronics housed within an ergonomic frame. Patientspecific accommodation deficiency models were utilized to demonstrate a high-fidelity accommodative correction. Each accommodation correction calculation was performed in ~67 ms requiring 4.86 mJ of energy. The optical resolution of the system was 10.5 cycles/degree, featuring a restorative accommodative range of 4.3 D. This system can run for up to 19 hours between charge cycles and weighs ~132 g, allowing comfortable restoration of accommodative function.