Models of Accommodation Deficiency in Presbyopia Patients

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.