title: Some methodological issues in the assessment of the spontaneous eyeblink frequency in man.
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.
authors.affiliation: Department of Vision Sciences, Glasgow-Caledonian University, UK.
authors.forename: M L
authors.initials: ML
authors.lastname: Zaman
authors.forename: M J
authors.initials: MJ
authors.lastname: Doughty
mesh_terms: D000328:Adult; D001767:Blinking; D005260:Female; D006801:Humans; D008297:Male; D015588:Observer Variation; D009885:Ophthalmology / Q000379:methods; D010507:Periodicity; D012016:Reference Values; D013223:Statistics as Topic; D013997:Time Factors; D014741:Video Recording