Validity and reliability of visual acuity measurements

A more scientific method than the Snellen chart for determining visual acuity is imperative for research studies and is desirable in many clinical situations. The psychometric method using the constant contour interaction S‐chart of Flom has been regarded as an accurate and reliable visual acuity measure and has been used widely for research purposes. This paper compares visual acuity measured by the S‐chart with that measured by the Snellen and Bailey‐Lovie charts. The results indicate that the Baily‐Lovie chart is a valid, reliable and rapid method of measuring threshold visual acuity for research purposes.

[1]  V. Dreyer,et al.  Visual acuity. , 1974, Ophthalmologica. Journal international d'ophtalmologie. International journal of ophthalmology. Zeitschrift fur Augenheilkunde.

[2]  K. N. Ogle.  On the problem of an international nomenclature for designating visual acuity. , 1953, American journal of ophthalmology.

[3]  D S Friendly,et al.  An automated visual acuity testing computer program using the Apple II system. , 1985, American journal of ophthalmology.

[4]  A J Bron,et al.  Detection of optic nerve damage in ocular hypertension. , 1985, The British journal of ophthalmology.

[5]  J M Wild,et al.  SOME STATISTICAL CONCEPTS IN THE ANALYSIS OF VISION AND VISUAL ACUITY , 1985, Ophthalmic & physiological optics : the journal of the British College of Ophthalmic Opticians.

[6]  A. Safir,et al.  Rationale for and design of the National Eye Institute Prospective Evaluation of Radial Keratotomy (PERK) Study. , 1983, Ophthalmology.

[7]  C. Schor,et al.  The Use of Rotating Gratings for the Treatment of Amblyopia: A Clinical Trial , 1981, American journal of optometry and physiological optics.

[8]  I L Bailey,et al.  New Design Principles for Visual Acuity Letter Charts* , 1976, American journal of optometry and physiological optics.

[9]  C. Ramsdale.  The effect of ametropia on the accommodative response , 1985, Acta ophthalmologica.

[10]  B. Wick,et al.  A comparison of the Snellen chart and the S-chart for visual acuity assessment in amblyopia. , 1984, Journal of the American Optometric Association.

[11]  S. Tinning,et al.  A new method for exact measurements of visual acuity , 1986, Acta ophthalmologica.

[12]  L G Carney,et al.  Visual loss in keratoconus. , 1982, Archives of ophthalmology.

[13]  S. Piermarocchi,et al.  Retinal fluorescein leakage in retinitis pigmentosa. , 1986, American journal of ophthalmology.

[14]  H. Bedell,et al.  Variations in the Slope of the Psychometric Acuity Function with Acuity Threshold and Scale , 1985, American journal of optometry and physiological optics.

[15]  J. Lewis,et al.  Digital visual acuity test using calculator-type numerals with geometric gradation. , 1987, Ophthalmology.

[16]  N. Drasdo,et al.  A COMPARISON OF THE BRITISH NUMBER PLATE AND SNELLEN VISION TESTS FOR CAR DRIVERS , 1981, Ophthalmic & physiological optics : the journal of the British College of Ophthalmic Opticians.

[17]  D. Wong,et al.  Computer automated visual acuity testing for visual screening. , 1986, Transactions of the ophthalmological societies of the United Kingdom.

[18]  H R Taylor,et al.  Applying new design principles to the construction of an illiterate E chart. , 1978, American journal of optometry and physiological optics.

[19]  M C FLOM,et al.  VISUAL RESOLUTION AND CONTOUR INTERACTION. , 1963, Journal of the Optical Society of America.

[20]  F. Ferris,et al.  New visual acuity charts for clinical research. , 1982, American journal of ophthalmology.

[21]  J E Sheedy,et al.  Visual Acuity and Chart Luminance , 1984, American journal of optometry and physiological optics.

[22]  American Foundation for the Blind , 1967 .

[23]  L L Sloan,et al.  Needs for precise measures of acuity. Equipment to meet these needs. , 1980, Archives of ophthalmology.

[24]  Ian L. Bailey,et al.  Task Complexity and Visual Acuity in Senile Macular Degeneration , 1981 .

[25]  J. Gaddum.  Probit Analysis , 1948, Nature.

[26]  D. Mitchell,et al.  Clinical trial of the use of rotating grating patterns in the treatment of amblyopia. , 1980, The British journal of ophthalmology.

[27]  Automated clinical visual acuity testing. , 1980, American journal of ophthalmology.

[28]  P. A. Ward,et al.  Effect of pupil size on steady state accommodation , 1985, Vision Research.

[29]  R. Rabbetts,et al.  Validity and reliability of visual acuity measurements , 1989, Ophthalmic & physiological optics : the journal of the British College of Ophthalmic Opticians.

[30]  D A Atchison,et al.  The Effect of Pupil Size on Visual Acuity in Uncorrected and Corrected Myopia , 1979, American journal of optometry and physiological optics.

[31]  G. Westheimer.  Scaling of visual acuity measurements. , 1979, Archives of ophthalmology.

[32]  G Strong,et al.  A distance visual acuity chart incorporating some new design features. , 1985, Archives of ophthalmology.