Accommodative response to peripheral stimuli in myopes and emmetropes.
OBJECTIVE
It has been suggested that peripheral refractive error may influence eye growth and the development of axial refractive error, implying that the peripheral retina is sensitive to defocus. This study aimed to evaluate the steady-state accommodative response to peripheral stimuli in 10 young, adult myopes (mean spherical equivalent error -2.10 ± 1.72 D, median -1.63 D, range -0.83 to -6.00 D) and 10 emmetropes (mean spherical equivalent error -0.02 ± 0.35 D, median +0.08 D, range -0.50 to +0.50 D).


METHODS
The subjects were asked to view monocularly the centre of a screen displaying each of a series of eccentric accommodative targets placed at 5, 10 and 15°. An axial target was viewed for comparison purposes. Accommodation was measured using an open-field autorefractor, each stimulus being varied between about 0 and 4 D with spherical trial lenses placed in front of the viewing eye.


RESULTS
The results confirm that the peripheral retina is sensitive to optical focus, up to field angles of at least 15°, with accommodative responses weakening as the peripheral angle increases. There is some evidence that peripheral accommodation may be less effective in myopes than emmetropes.


CONCLUSIONS
Although peripheral accommodation can be demonstrated in the absence of a central stimulus, the accommodation response is normally dominated by the central stimulus and it seems unlikely that peripheral accommodation effects play an important role in refractive development.
Faculty of Life Sciences, University of Manchester, Manchester, UK.
Andreas
A
Hartwig
W Neil
WN
Charman
Hema
H
Radhakrishnan
D000065:Accommodation, Ocular / Q000502:physiology*; D000328:Adult; D058453:Emmetropia / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D009216:Myopia / Q000503:physiopathology*; D010775:Photic Stimulation / Q000379:methods; D012160:Retina / Q000503:physiopathology; D014794:Visual Fields / Q000502:physiology; D055815:Young Adult