No abstract

Previous assessments of spontaneous eyeblink frequency (SEBF) or interblink intervals (IBI) have been made over period of 0.5 to 15 min and average values calculated; the reliability of the methods has not been validated. Video recordings were made of 14 healthy volunteers, aged 20 to 38 years, while silently fixating on a 2 m distant, 35 mm high target under 350 lux illumination and the traces assessed with an event marker. Significant fluctuations in SEBF or IBI were generally observed, but which did not conform to a minute-by-minute periodicity. Time-dependent trends were uncommon, although uncritical pooling or averaging of data can effectively conceal such fluctuations or trends. Correlation's between SEBF and IBI indicate that eyeblink monitoring over at least 3 min is required. Simple averaging calculations are not appropriate because of a high chance of non-Gaussian distribution of data. Modal IBI values correlated well with an adjusted modal calculated SEBF which is thus recommended for further use.

No abstract