PURPOSE: The Freiburg Visual Acuity Test (FrACT) has been suggested as a promising test for quantifying the visual acuity (VA) of patients with very low vision, a condition often classified using the semi-quantitative clinical scale "counting fingers" (CF), "hand motion" (HM), "light perception" (LP) and "no light perception". The present study was designed to assess FrACT performance in a sizable number of CF, HM, and LP patients in order to generate a setting for future clinical studies in the low vision range. METHODS: We examined a total of 41 patients (LP, n = 11; CF, n = 15; HM, n = 15) with various eye diseases (e.g., diabetic retinopathy, ARMD), covering the clinical VA scale from LP to CF. The FrACT optotypes were presented at a distance of 50 cm on a 17-inch LCD monitor with four random orientations. After training, two FrACT measurements (test and retest) were taken, each comprising 30 trials. RESULTS: FrACT measures reproducibly the VA of CF and HM patients. In CF patients, FrACT resulted in a mean logMAR = 1.98 +/- 0.24 (corresponding to a decimal VA of 0.010), for HM in a mean logMAR = 2.28 +/- 0.15 (corresponding to a decimal VA of 0.0052). In all LP patients the FrACT values were close to what would be obtained by random guessing. The mean test-retest 95% confidence interval was 0.21 logMAR for CF patients and 0.31 logMAR for HM respectively. Test-retest variability declined from 24 to 30 trials, showing that at least 30 trials are necessary. CONCLUSION: FrACT can reproducibly quantify VA in the CF and HM range. We observed a floor effect for LP, and it was not quantifiable further. Quantitative VA measures are thus obtainable in the very low-vision range using FrACT.
PURPOSE: The Freiburg Visual Acuity Test (FrACT) has been suggested as a promising test for quantifying the visual acuity (VA) of patients with very low vision, a condition often classified using the semi-quantitative clinical scale "counting fingers" (CF), "hand motion" (HM), "light perception" (LP) and "no light perception". The present study was designed to assess FrACT performance in a sizable number of CF, HM, and LPpatients in order to generate a setting for future clinical studies in the low vision range. METHODS: We examined a total of 41 patients (LP, n = 11; CF, n = 15; HM, n = 15) with various eye diseases (e.g., diabetic retinopathy, ARMD), covering the clinical VA scale from LP to CF. The FrACT optotypes were presented at a distance of 50 cm on a 17-inch LCD monitor with four random orientations. After training, two FrACT measurements (test and retest) were taken, each comprising 30 trials. RESULTS: FrACT measures reproducibly the VA of CF and HM patients. In CF patients, FrACT resulted in a mean logMAR = 1.98 +/- 0.24 (corresponding to a decimal VA of 0.010), for HM in a mean logMAR = 2.28 +/- 0.15 (corresponding to a decimal VA of 0.0052). In all LPpatients the FrACT values were close to what would be obtained by random guessing. The mean test-retest 95% confidence interval was 0.21 logMAR for CF patients and 0.31 logMAR for HM respectively. Test-retest variability declined from 24 to 30 trials, showing that at least 30 trials are necessary. CONCLUSION: FrACT can reproducibly quantify VA in the CF and HM range. We observed a floor effect for LP, and it was not quantifiable further. Quantitative VA measures are thus obtainable in the very low-vision range using FrACT.
Authors: Richard J Dennis; Jeremy M A Beer; J Bruce Baldwin; Douglas J Ivan; Frank J Lorusso; William T Thompson Journal: Optom Vis Sci Date: 2004-07 Impact factor: 1.973
Authors: S Grover; G A Fishman; R J Anderson; M S Tozatti; J R Heckenlively; R G Weleber; A O Edwards; J Brown Journal: Ophthalmology Date: 1999-09 Impact factor: 12.079
Authors: Stephen Russell; Jean Bennett; Jennifer A Wellman; Daniel C Chung; Zi-Fan Yu; Amy Tillman; Janet Wittes; Julie Pappas; Okan Elci; Sarah McCague; Dominique Cross; Kathleen A Marshall; Jean Walshire; Taylor L Kehoe; Hannah Reichert; Maria Davis; Leslie Raffini; Lindsey A George; F Parker Hudson; Laura Dingfield; Xiaosong Zhu; Julia A Haller; Elliott H Sohn; Vinit B Mahajan; Wanda Pfeifer; Michelle Weckmann; Chris Johnson; Dina Gewaily; Arlene Drack; Edwin Stone; Katie Wachtel; Francesca Simonelli; Bart P Leroy; J Fraser Wright; Katherine A High; Albert M Maguire Journal: Lancet Date: 2017-07-14 Impact factor: 79.321
Authors: P Yu-Wai-Man; P G Griffiths; G S Gorman; C M Lourenco; A F Wright; M Auer-Grumbach; A Toscano; O Musumeci; M L Valentino; L Caporali; C Lamperti; C M Tallaksen; P Duffey; J Miller; R G Whittaker; M R Baker; M J Jackson; M P Clarke; B Dhillon; B Czermin; J D Stewart; G Hudson; P Reynier; D Bonneau; W Marques; G Lenaers; R McFarland; R W Taylor; D M Turnbull; M Votruba; M Zeviani; V Carelli; L A Bindoff; R Horvath; P Amati-Bonneau; P F Chinnery Journal: Brain Date: 2010-02-15 Impact factor: 13.501