Key words: logMAR acuity, Snellen acuity, visual ... sively for the measurement of visual acuity (VA) for ... thereby making data scoring and analysis easier.
S Afr Optom 2009 68(3) 155-163
A comparison of two methods of logMAR visual acuity data scoring for statistical analysis †OA Oduntan, *KP Mashige and **M Raliavhegwa-Makhado †,*Discipline of Optometry, School of Physiotherapy, Sport Science and Optometry, Faculty of Health Sciences, University of KwaZulu-Natal, Private Bag X 54001, Durban, 4000 South Africa **Department of Optometry, University of Limpopo, Private Bag X1106, Sovenga, 0727 South Africa Received 29 March 2009; revised version accepted 2 September 2009
Abstract The purpose of this study was to compare two methods of logMAR visual acuity (VA) scoring. The two methods are referred to as letter scoring (method 1) and line scoring (method 2). The two methods were applied to VA data obtained from one hundred and forty (N=140) children with oculocutaneous albinism. Descriptive, correlation and regression statistics were then used to analyze the data. Also, where applicable, the Bland and Altman analysis was used to compare sets of data from the two methods. The right and left eyes data were included in the study, but because the findings were similar in both eyes, only the results for the right eyes are presented in this paper. For method 1, the mean unaided VA (mean UAOD1) = 0.39 ± 0.15 logMAR. The mean aided (mean ADOD1) VA = 0.50 ± 0.16 logMAR. For method 2, the mean unaided (mean UAOD2) VA = 0.71 ± 0.15 log-
Introduction Snellen VA charts and notations are used extensively for the measurement of visual acuity (VA) for clinical, research and socio-legal purposes, but various deficiencies in the charts have been highlighted by various authors1, 2. The (logMAR) method of acuity scaling devised by Bailey and Lovie1 is now considered to be more appropriate for scaling VA meas-
MAR, while the mean aided VA (mean ADOD2) = 0.60 ± 0.16 logMAR. The range and mean values of the improvement in VA for both methods were the same. The unaided VAs (UAOD1, UAOD2) and aided (ADOD1, ADOD2) for methods 1 and 2 correlated negatively (Unaided, r = –1, p
