| Budget Amount *help |
¥1,500,000 (Direct Cost: ¥1,500,000)
Fiscal Year 2001: ¥800,000 (Direct Cost: ¥800,000)
Fiscal Year 2000: ¥700,000 (Direct Cost: ¥700,000)
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| Research Abstract |
1) To clarify whether myopes have a .larger accommodative lag. 43 adults were classified into early-onset myopia (EOM) and emmetropia (EMM) groups. Accommodative responses to accommodative targets were objectively measured. Under a binocular condition, the accommodative lag for each target was significantly smaller in the EOM group, but the mean slope of the accommodative stimulus-response function did not differ between the EOM and EMM groups. The mean slope under a binocular condition was significantly steeper than that under a monocular condition in both groups. In adults with EOM, the accommodative function was not impaired, and the habitual accommodative lag was small, due to the reduced accommodative demand by a vertex distance and/or the under-correction of spectacles.
2) A model of crosslink interactions between accommodation and convergence predicts that the demand of fusional vergence to compensate for heterophoria can induce large accommodative errors. We tested this interaction in heterophoric patients. The subjects were 109 individuals consisting of exophoria or esophoria who showed binocular fusion and normal controls. Accommodative responses to a 2.5D target were objectively measured in monocular occluded (MOC) and binocular fused (BFC) conditions and compared. The accommodative errors in RFC ranged from an accommodative lag of 1.8 D to an accommodative lead of 1.6 D. A linear relationship was found between the difference in the response between MOC and BFC and heterophoric angle. The magnitude of the accommodative lag in BFC was correlated with esophoria and uncorrected hyperopia, and the strength of correlations varied with AC/A and CA/C ratios. In heterophoric patients, heterophoria affects accommodative responses to various degrees as the model predicted, and accommodation disorders sometimes occurr in exchange for binocular fusion.
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