Accommodation responses in late‐onset myopia are improved by spatiotopic stimulation

Abstract

Purpose: Inaccurate accommodation responses to retinotopic stimuli have been shown in late‐onset myopia (LOM). The aim of this experiment was to determine whether spatiotopic (perceived proximity) and binocular stimulation would improve the quality of accommodation responses in LOM subjects.Methods: Ten emmetropic subjects (mean age 22.3 ± 2.3 years) and 10 LOM subjects (mean age 21.8 ± 1.5 years) participated. A specially modified Canon R‐1 infrared optometer was used to measure accommodation responses. Three conditions were presented: (1) Monocular blur‐only stimulus, (2) Monocular free‐space stimulus, and (3) Binocular free‐space stimulus. Each condition was presented on a separate day to avoid fatigue effects.Results: Accommodation stimulus–response curves in the LOM group showed improved accuracy with the spatiotopic stimulus. Microfluctuations were significantly (p < 0.01) smaller in magnitude in the LOM group with the spatiotopic stimulus, because of reductions in the low frequency components of the fluctuations. A significant (p < 0.01) increase in the percentage of correct step accommodation responses for the spatiotopic stimulus was found in the LOM group. However, step response times in the LOM group with the spatiotopic stimulus were not significantly different than those found with the retinotopic stimulus, and were significantly (p < 0.01) longer than those found in the emmetropic group.Conclusions: (1) Spatiotopic stimulation produces significant improvements in static accommodative accuracy in LOM subjects compared with retinotopic stimulation. (2) The quality of dynamic accommodation responses in LOM subjects was found to improve significantly with spatiotopic stimulation. (3) LOM subjects appear to rely upon proximity driven stimuli to improve accommodative response accuracy.