Real-Time Objective Measurement of Accommodation While Reading

Purpose: In the clinical care of functional vision disorders, dynamic retinoscopy such as Monocular Estimate Method has been the mainstay for objective measurement of the accommodative response. It is valuable, fast and widely available. Dynamic retinoscopy however does not allow for quantified measures of accommodation by inexperienced clinicians or technicians. Automated, objective methods for performing simple clinical tests like book retinoscopy would be most useful, if only real-world targets like continuous text could be included. This study was aimed at determining the feasibility of collecting automated, continuous accommodative data during reading. Methods: Real-time accommodative measurements were measured on nine subjects under three conditions while accommodative measurements were collected at 5Hz with the Grand Seiko WAM-5500 open-field autorefractor. The first two conditions tested the ability of the autorefractor to measure accommodative response using peripheral gaze: with distant and near targets. The third condition involved reading from the electronically presented text. Results: Accommodative response, allowing for expected accommodative lag, was measured within 0.25 D of expected clinical values during reading in a 3-line vertical, 15-degree horizontal window. Conclusions: Within the 15o visual angle range, open-field autorefraction is able to accurately measure the realtime accommodative response to within 0.25 D. Although there are dynamic fluctuations in the accommodative response during reading, measured accommodative lag increases with demand and is consistent with the literature on dynamic retinoscopy. Open-field autorefraction has the potential to demonstrate accommodative dysfunction when used in real-time mode.