Resolving the clinical acuity categories “hand motion” and “counting fingers” using the Freiburg Visual Acuity Test (FrACT)

  • C. Lange
  • N. Feltgen
  • B. Junker
  • K. Schulze-Bonsel
  • M. BachEmail author
Low Vision



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.


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.


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.


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.


Visual acuity Low-vision assessment Psychophysics 


  1. 1.
    Early Treatment Diabetic Retinopathy Study Group (1991) Early Treatment Diabetic Retinopathy Study design and baseline patient characteristics. ETDRS report number 7. Ophthalmology 98:741–756Google Scholar
  2. 2.
    Arditi A, Cagenello R (1993) On the statistical reliability of letter-chart visual acuity measurements. Invest Ophthalmol Vis Sci 34:120–129PubMedGoogle Scholar
  3. 3.
    Bach M (1996) The Freiburg Visual Acuity Test – Automatic measurement of visual acuity. Optom Vis Sci 73:49–53, doi: 10.1097/00006324-199601000-00008 PubMedCrossRefGoogle Scholar
  4. 4.
    Bach M (1997) Anti-aliasing and dithering in the Freiburg Visual Acuity Test. Spat Vis 11:85–89, doi: 10.1163/156856897X00087 PubMedCrossRefGoogle Scholar
  5. 5.
    Bach M (2006) Homepage of the Freiburg Visual Acuity and Contrast Test (‘FrACT’). Retrieved 2007-04-17, from <>;
  6. 6.
    Bach M (2007) The Freiburg Visual Acuity Test-Variability unchanged by post-hoc re-analysis. Graefes Arch Clin Exp Ophthalmol 245:965–971, doi: 10.1007/s00417-006-0474-4 PubMedCrossRefGoogle Scholar
  7. 7.
    Beck RW, Moke PS, Turpin AH, Ferris FL 3rd, SanGiovanni JP, Johnson CA et al (2003) A computerized method of visual acuity testing: adaptation of the early treatment of diabetic retinopathy study testing protocol. Am J Ophthalmol 135:194–205, doi: 10.1016/S0002-9394(02)01825-1 PubMedCrossRefGoogle Scholar
  8. 8.
    Colenbrander A (2002) Visual standards aspects and ranges of vision loss with emphasis on Population Surveys. Report prepared for the International Council of Ophthalmology at the 29th International Congress of Ophthalmology Sydney, Australia, April 2002Google Scholar
  9. 9.
    Colenbrander A, Fletcher DC (1990) Visual acuity measurements in low vision patients. J Vis Rehab 4:1–9Google Scholar
  10. 10.
    Dennis RJ, Beer JM, Baldwin JB, Ivan DJ, Lorusso FJ, Thompson WT (2004) Using the Freiburg Acuity and Contrast Test to measure visual performance in USAF personnel after PRK. Optom Vis Sci 81:516–524, doi: 10.1097/00006324-200407000-00013 PubMedCrossRefGoogle Scholar
  11. 11.
    Ferris FL 3rd, Kassoff A, Bresnick GH, Bailey I (1982) New visual acuity charts for clinical research. Am J Ophthalmol 94:91–96PubMedGoogle Scholar
  12. 12.
    Grover S, Fishman GA, Anderson RJ, Tozatti MS, Heckenlively JR, Weleber RG et al (1999) Visual acuity impairment in patients with retinitis pigmentosa at age 45 years or older. Ophthalmology 106:1780–1785, doi: 10.1016/S0161-6420(99)90342-1 PubMedCrossRefGoogle Scholar
  13. 13.
    Holladay JT (1997) Proper method for calculating average visual acuity. J Refract Surg 13:388–391PubMedGoogle Scholar
  14. 14.
    Kiser AK, Mladenovich D, Eshraghi F, Bourdeau D, Dagnelie G (2005) Reliability and consistency of visual acuity and contrast sensitivity measures in advanced eye disease. Optom Vis Sci 82:946–954, doi: 10.1097/01.opx.0000187863.12609.7b PubMedCrossRefGoogle Scholar
  15. 15.
    Lieberman HR, Pentland AP (1982) Microcomputer-based estimation of psychophysical thresholds: The best PEST. Behav Res Meth Instrum 14:21–25Google Scholar
  16. 16.
    Loumann Knudsen L (2003) Visual acuity testing in diabetic subjects: the decimal progression chart versus the Freiburg visual acuity test. Graefes Arch Clin Exp Ophthalmol 241:615–618, doi: 10.1007/s00417-003-0707-8 PubMedCrossRefGoogle Scholar
  17. 17.
    Schulze-Bonsel K, Feltgen N, Burau H, Hansen LL, Bach M (2006) Visual acuities “Hand Motion” and “Counting Fingers” can be quantified using the Freiburg Visual Acuity Test. Invest Ophthalmol Vis Sci 47:1236–1240, doi: 10.1167/iovs.05-0981 PubMedCrossRefGoogle Scholar
  18. 18.
    Treutwein B (1995) Adaptive psychophysical procedures. Vision Res 35:2503–2522PubMedGoogle Scholar
  19. 19.
    Wesemann W (2002) Visual acuity measured via the Freiburg visual acuity test (FVT), Bailey Lovie chart and Landolt Ring chart. Klin Monatsbl Augenheilkd 219:660–667, doi: 10.1055/s-2002-35168 PubMedCrossRefGoogle Scholar
  20. 20.
    World Medical Association (2000) Declaration of Helsinki: ethical principles for medical research involving human subjects. JAMA 284:3043–3045, doi: 10.1001/jama.284.23.3043 CrossRefGoogle Scholar

Copyright information

© Springer-Verlag 2008

Authors and Affiliations

  • C. Lange
    • 1
  • N. Feltgen
    • 1
  • B. Junker
    • 1
  • K. Schulze-Bonsel
    • 1
  • M. Bach
    • 1
    • 2
    Email author
  1. 1.Department of OphthalmologyUniversity of FreiburgFreiburgGermany
  2. 2.Universitäts-Augenklinik FreiburgFreiburgGermany

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