Abstract
Purpose :
Inaccurate accommodation responses (AR) to blur may be associated with myopia development. We compared static and dynamic AR over time in young emmetropic children at either low (LR) or high risk (HR) for myopia, determined by parental myopia and baseline refractive error.
Methods :
Static and dynamic AR were measured on the right eyes of young children (N=92, 7.46 ± 0.96yrs) with functional emmetropia at baseline (SE OD +1.01 ± 0.55D; AXL OD 22.76 ± 0.64mm) using a WAM-5500 open-field binocular autorefractor WMT-2 Moving System (Ait, Luneau). These measures were repeated over 5 visits (every 6 months, M, for 24M). ‘Dead leaves’ stimuli which capture spatial characteristics of natural images were used under two conditions, a real object (3D), and a flat, 2D picture of the object. Static AR were measured for a 2.50D demand. Dynamic AR were measured for sinusoidally moving stimuli (27 seconds, 1-4D demand, 9 sec-cycles) and results fitted with sinusoidal functions. At visit 5 (M24), a separate measure was taken to compare 2D and 3D stimuli while viewing binocularly.
Results :
The monocular accuracy of static accommodation significantly decreased (greater lags) after M18 both the LR (p<0.001) and HR (p<0.001) groups. Children at LR for myopia had greater accuracy of accommodation (lower lags) from baseline to M18 (p<0.01 for all) compared to those at HR, but not at M24 (p=0.359). Children at LR for myopia had greater AR at all visits (p<0.01 for all). This difference became greater under binocular conditions. Dynamic monocular AR were not different over time in the LR (p=0.13) or HR (p=0.59) groups. Under binocular conditions, children at LR have greater AR than those at HR for 2D (LR=3.94 ± 0.52D, HR=3.22 ± 0.84D, p<0.001) and 3D stimuli (LR=3.78 ± 0.74D, HR=3.23 ± 0.89D, p=0.003). Similarly, while viewing binocularly, children at LR have more accurate AR (lower lags) for 2D (LR=0.91 ± 0.60D, HR=1.10 ± 0.51D, p=0.003) and 3D stimuli (LR=0.62 ± 0.51D, HR=0.90 ± 0.51D, p=0.01).
Conclusions :
Children at LR for myopia consistently show more accurate accommodation and larger responses, particularly under binocular viewing conditions. Further study is necessary to explore the impact of stimuli depth on myopia development, especially as some of the children develop myopia during the study. Differences in AR in young children may be useful in predicting the development of myopia.
This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.