Abstract
Purpose :
Inaccurate accommodation responses to blur may be associated with myopia. Conflicting results in previous studies may be a result of varied stimuli characteristics. We sought to compare static and dynamic accommodation responses (AR) and associated pupil constriction to two different stimuli in children.
Methods :
Static and dynamic AR and pupil sizes were measured on the right eyes of young children (N=97, 7.58±0.96yrs) with functional emmetropia (SE OD +0.95±0.54D; AXL OD 22.79±0.75mm) using a WAM-5500 open-field binocular autorefractor WMT-2 Moving System (Ait, Luneau). Two targets of ‘dead leaves’ stimuli which capture spatial characteristics of natural images were used: the real object (3D), and a flat, 2D picture of the same object. Static AR were measured for a 2.5D demand. Dynamic AR were measured for a sinusoidally moving stimuli (27 seconds, 1-4D demand, 9 second-cycles) and results fitted with sinusoidal functions. Children were classified into High Risk (HR) or Low Risk (LR) for myopia based on their parental myopia and baseline refractive error.
Results :
Static AR for a 2.5D demand did not differ significantly between the 2D (1.79±0.45D) and 3D (1.75±0.51D) stimuli (p>0.05). Pupil sizes were also not significantly different (2D: 5.89±0.89mm, 3D: 5.97±0.85mm; p>0.05). Children at LR for myopia accommodated significantly more accurately than those at HR when viewing both static 2D (LR: 1.89±0.48D, HR: 1.68±0.38D; p=0.006) and 3D stimuli (LR: 1.83±0.62D, HR: 1.65±0.34D; p=0.007). Dynamic accommodation amplitudes were larger for the 2D (1.27±0.21D) than the 3D (1.24±0.23D, p=0.025) stimuli, and latencies longer for the 3D stimuli (2D: 0.34±0.22msec, 3D: 0.42±0.28msec; p=0.008). AR amplitudes were significantly larger for children at LR compared to those at HR for myopia (2D - LR: 1.31±0.17D, HR: 1.22±0.19D; p=0.037; 3D - LR: 1.32±0.18D, HR: 1.15±0.23D; p<0.001) stimuli.
Conclusions :
No overall differences were found between the 2D and 3D stimuli for static responses, but the dynamic amplitudes and latencies were more accurate with the 2D compared to the 3D stimuli. Children with LR for myopia showed more accurate static and dynamic responses than those at HR for myopia. Differences in AR in young children may predict the development of myopia.
This abstract was presented at the 2022 ARVO Annual Meeting, held in Denver, CO, May 1-4, 2022, and virtually.