title: Tonic accommodation predicts closed-loop accommodation responses.
abstract: The purpose of this study is to examine the potential relationship between tonic accommodation (TA), near work induced TA-adaptation and the steady state closed-loop accommodation response (AR). Forty-two graduate students participated in the study. Various aspects of their accommodation system were objectively measured using an open-field infrared auto-refractor (Grand Seiko WAM-5500). Tonic accommodation was assessed in a completely dark environment. The association between TA and closed-loop AR was assessed using linear regression correlations and t-test comparisons. Initial mean baseline TA was 1.84diopter (D) (SD±1.29D) with a wide distribution range (-0.43D to 5.14D). For monocular visual tasks, baseline TA was significantly correlated with the closed-loop AR. The slope of the best fit line indicated that closed-loop AR varied by approximately 0.3D for every 1D change in TA. This ratio was consistent across a variety of viewing distances and different near work tasks, including both static targets and continuous reading. Binocular reading conditions weakened the correlation between baseline TA and AR, although results remained statistically significant. The 10min near reading task with a 3D demand did not reveal significant near work induced TA-adaptation for either monocular or binocular conditions. Consistently, the TA-adaptation did not show any correlation with AR during reading. This study found a strong association between open-loop TA and closed-loop AR across a variety of viewing distances and different near work tasks. Difference between the correlations under monocular and binocular reading condition suggests a potential role for vergence compensation during binocular closed-loop AR.
authors.affiliation: Western University of Health Sciences, College of Optometry, Pomona, CA, United States. Electronic address: cliu1@westernu.edu.
authors.forename: Chunming
authors.initials: C
authors.lastname: Liu
authors.affiliation: Western University of Health Sciences, College of Optometry, Pomona, CA, United States; California State University Northridge, Northridge, CA, United States.
authors.forename: Stefanie A
authors.initials: SA
authors.lastname: Drew
authors.affiliation: Southern California College of Optometry at Marshall B. Ketchum University, Fullerton, CA, United States.
authors.forename: Eric
authors.initials: E
authors.lastname: Borsting
authors.affiliation: Western University of Health Sciences, College of Optometry, Pomona, CA, United States.
authors.forename: Amy
authors.initials: A
authors.lastname: Escobar
authors.affiliation: Southern California College of Optometry at Marshall B. Ketchum University, Fullerton, CA, United States.
authors.forename: Lawrence
authors.initials: L
authors.lastname: Stark
authors.affiliation: Western University of Health Sciences, College of Optometry, Pomona, CA, United States. Electronic address: cchase@westernu.edu.
authors.forename: Christopher
authors.initials: C
authors.lastname: Chase
mesh_terms: D000065:Accommodation, Ocular / Q000502:physiology*; D000221:Adaptation, Ocular / Q000502:physiology*; D000328:Adult; D003290:Convergence, Ocular / Q000502:physiology; D004215:Distance Perception / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D010775:Photic Stimulation / Q000379:methods; D012044:Regression Analysis; D015348:Vision, Binocular / Q000502:physiology; D055815:Young Adult
keywords: Accommodation response; TA-adaptation; Tonic accommodation; Vergence