Differences in adaptation of tonic accommodation with refractive state.

摘要: It has recently been demonstrated that intersubject variations in tonic (dark focus) levels of accommodation are related to corrected refractive state (McBrien and Millodot, 1987). The aim the present study was investigate effect sustained visual tasks on level different groups. Eleven hyperopes, 16 emmetropes, ten early onset myopes late had their measured with objective infrared optometer Canon Autoref R-1 before after a 15 min counting task. post-task monitored for assess decay rate any observed task-induced changes accommodation. Subjects repeated experimental procedure four task locations (6 m, pre-task position, 37 cm 20 cm). Late showed significant positive (myopic) at both near viewing distances, which no evidence during monitoring period. Hyperopes, however, underwent transient "counteradaptive" decreases viewing. Emmetropes little change two distances. Differences between groups were also obtained far Post-task only weak negative correlation each distance. is proposed differences adaptation among may be autonomic innervation ciliary muscle.