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Time‐of‐day variations in oculomotor function: 1. Tonic accommodation and tonic vergence
Author(s) -
Amerson Thomas L.,
Mershon Donald H.
Publication year - 1988
Publication title -
ophthalmic and physiological optics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.147
H-Index - 66
eISSN - 1475-1313
pISSN - 0275-5408
DOI - 10.1111/j.1475-1313.1988.tb01178.x
Subject(s) - tonic (physiology) , accommodation , evening , morning , time of day , psychology , medicine , neuroscience , biology , zoology , physics , astronomy
Time‐of‐day variations were studied both in tonic accomodation and in tonic vergence. Thirty‐six male volunteers were measured once in the morning and at one other time on the same day. The mean baseline value of tonic accomodation was 2.02 D. Time‐of‐day variations were found, with a late evening measure being + 0.6 D greater than the morning value. No independent time‐of‐day fluctuations were found in tonic vergence. Post‐hoc analysis, however, showed that tonic vergence tended to shift in the same direction as an individual's tonic accommodation during the afternoon. During the evening, tonic vergences tended to shift oppositely to tonic accommodation.