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Reliability of low contrast letter charts in different viewing conditions
Author(s) -
Pardham Shahina
Publication year - 1996
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 - 10.1046/j.1475-1313.1996.96833643.x
Subject(s) - repeatability , monocular , contrast (vision) , reliability (semiconductor) , glare , optometry , monocular vision , correlation coefficient , mathematics , audiology , statistics , artificial intelligence , computer science , medicine , materials science , physics , power (physics) , layer (electronics) , quantum mechanics , composite material
Test‐retest scores were obtained under binocular, monocular and monocular in the presence of conditions from 20 healthy older patients using the Pelli‐Robson and Regan (96% and 11% contrast) charts. Data were analysed using two indices: coefficients of repeatability and intra‐class correlation coefficients. Coefficient of repeatability determines the 95% confidence limits for change. The Regan 96% contrast chart showed the highest reliability under all viewing conditions. Comparing the different viewing conditions, binocular viewing showed the smallest coefficient of repeatability and the highest intra‐class correlation. Monocular viewing in the presence of glare showed the largest coefficient of repeatability and the lowest intra‐class coefficient. The results demonstrate the need for measuring reliability criteria under the appropriate viewing conditions when determining whether a significant change has occurred, e.g. with monocular glare scores in cataract or binocular performance in amblyopia.