FIELD: medicine; ophthalmology.
SUBSTANCE: distinct vision stability factor is used at the sight limit. The factor is defined as a ratio after and before visual load of a number of correctly delivered and articulated alphabetic characters of a literary text distanced at the sight limit. Angular dimensions of alphabetic characters are correlated with visual acuity nearby. Texts are shown for 1-3 minutes. If the factor is within 0.95 to 0.9, efficiency is estimated as slightly lowered. The factor 0.89 to 0.8 shows medium lowered efficiency, while severely lowered efficiency is indicated by the factor 0.8 or less.
EFFECT: objective estimate of visual efficiency with quantitative estimation of decrement degree.
1 tbl, 3 ex
