Beyond static assessment: dynamic accommodative behaviour across refractive states.

CLINICAL RELEVANCE: Understanding accommodative mechanisms across refractive errors is essential for improving the clinical assessment and management of refractive errors.

BACKGROUND

Dynamic accommodative assessment may improve detection of functional differences in refractive errors that are not evident in conventional clinical testing, where accommodative differences across refractive groups remain not fully understood. This study analysed dynamic accommodative behaviour and ocular optical quality during stimulus and post-stimulus phases in emmetropes, hyperopes, and myopes.

METHODS

The root-mean-square (RMS) of high-order aberrations (HOA), accommodative response, residual accommodation after stimuli, microfluctuations, and response times were assessed in 75 participants (36 emmetropes, 24 myopes, 15 hyperopes), with a mean age of 23.04 ± 3.67 years. Measurements were obtained in the relaxed state and during/after 1.00 D, 2.45 D, and 4.73 D stimuli using a real-time Shack-Hartmann aberrometer.

RESULTS

Accommodative responses did not differ significantly between refractive groups at any stimulus level (p > 0.05). Hyperopes showed significantly higher residual accommodation after the 2.45 D (p = 0.001) and 4.73 D (p = 0.003) stimuli, and myopes exhibited significantly higher residual accommodation after the 4.73 D stimulus (p = 0.03). Myopes demonstrated increased microfluctuations at 2.45 D (p = 0.013) and after removal of the 4.73 D stimulus (p < 0.01), relative to baseline, indicating greater accommodative instability. Hyperopes showed significantly higher RMS HOA in the relaxed state than emmetropes (p = 0.028) and myopes (p = 0.009), and after removal of the 4.73 D stimulus than myopes (p = 0.009). No significant differences were found in accommodative or disaccommodative response times.

CONCLUSION

Although accommodative responses during stimulation were similar across refractive groups, hyperopes and myopes showed incomplete accommodative relaxation after higher demands, and myopes exhibited greater instability during and after accommodation. Residual accommodation and microfluctuations provide valuable insights into dynamic accommodative behaviour across refractive errors.