Accommodative lag under habitual seeing conditions: comparison between adult myopes and emmetropes.
OBJECTIVE
To clarify whether myopes show poor accommodative response and thus have a larger accommodative lag under natural seeing conditions.


METHODS
Forty-three adults without other ocular abnormalities were classified into the early-onset myopia (EOM, n=28) and the emmetropia (EMM, n=15) groups. The subjects wore glasses or contact lenses that they habitually used, and accommodative responses to four accommodative targets (16.0-50.5 cm from their eyes) were measured under a monocular or binocular condition using an open-field infrared autorefractometer.


RESULTS
Under a binocular condition, the accommodative lag for each target was significantly smaller in the EOM group (analysis of variance, P<.01), but the mean slope of the accommodative stimulus-response function did not significantly differ between the EOM and EMM groups (1.05+/-0.11 and 1.02+/-0.10 D/D, respectively). The mean slope under a binocular condition was significantly steeper than that under a monocular condition in both groups (paired t-test, P<.05).


CONCLUSIONS
In adults with EOM, the accommodative stimulus-response function was not impaired, and the habitual accommodative lag was rather small, probably due to the reduced accommodative demand by a vertex distance and/or the intentional undercorrection of spectacles.
Nakatsuka
Chiaki
C
Department of Ophthalmology, Okayama University Graduate School of Medicine and Dentistry, Okayama, Japan.
Hasebe
Satoshi
S
Nonaka
Fumitaka
F
Ohtsuki
Hiroshi
H
D000065:Accommodation, Ocular / Q000502:physiology*; D000328:Adult; D005260:Female; D006801:Humans; D008297:Male; D009216:Myopia / Q000503:physiopathology*; D014787:Vision Tests; D015348:Vision, Binocular / Q000502:physiology*; D014796:Visual Perception / Q000502:physiology