Abstract
Purpose
To estimate the specificity of a clinical evaluation of a series of visual fields and to calculate the positive predictive value of progression.
Methods
The specificity of a clinical evaluation of a series of visual fields was estimated using nonparametric ranking and probability calculus. The positive predictive value of progression was calculated using Bayes’ theorem. The literature suggests a prior probability of progression of typically 0.10 in the case of one visual field per year. Three different prior probability values were used: 0.05, 0.10, and 0.20. Calculations were performed for a sensitivity of 0.50, 0.80, and 1.00.
Results
Specificity of a clinical evaluation of a series of visual fields was calculated as 0.83 for four fields (two baseline fields, one follow-up field with suspected progression, and one confirmation of the suspected progression), 0.90 for five fields, and 0.95 for six fields. Positive predictive values ranged from 0.14 to 0.83. Positive predictive value was approximately 0.5 for a prior probability of 0.10, a sensitivity of 0.80, and a specificity of 0.90.
Conclusions
Realistic series of visual fields that are apparently progressive have a positive predictive value of typically 0.5, i.e., half of them are stable. In the case of a high prior probability (uncontrolled glaucoma or long interval between successive fields), four fields may suffice to diagnose progression, whereas at least six fields are required if the prior probability is low.
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References
AGIS investigators (1994) Advanced glaucoma intervention study 2: visual field test scoring and reliability. Ophthalmology 101:1445–1455
Altman DG (1991) Practical statistics for medical research. Chapman & Hall, London
Bland JM, Altman DG (1986) Statistical methods for assessing agreement between two methods of clinical measurement. Lancet 1:307–310
Chauhan BC, Drance SM, Douglas GR (1990) The use of visual field indices in detecting changes in the visual field in glaucoma. Invest Ophthalmol Vis Sci 31:512–520
Esterman B (1968) Grid for scoring visual fields. Arch Ophthalmol 79:400–406
Fitzke FW, Hitchings RA, Poinoosawmy D, McNaught AI, Crabb DP (1996) Analysis of visual field progression in glaucoma. Br J Ophthalmol 80:40–48
Gardiner SK, Crabb DP (2002) Frequency of testing for detecting visual field progression. Br J Ophthalmol 86:560–564
Heijl A, Leske MC, Bengtsson B, Bengtsson B, Hussein M, EMGT group (2003) Measuring visual field progression in the early manifest glaucoma trial. Acta Ophthalmol Scand 81:286–293
Heijl A, Leske MC, Bengtsson B, Hyman L, Bengtsson B, Hussein M, EMGT group (2002) Reduction of intraocular pressure and glaucoma progression. Arch Ophthalmol 120:1268–1279
Heijl A, Lindgren G, Lindgren A, Olsson J, Asman P, Myers S, Patella M (1990) Extended empirical statistical package for evaluation of single and multiple fields in glaucoma: Statpac 2. In: Mills RP, Heijl A (eds) Perimetry update 1990/1. Kugler, New York, pp 305–315
Heijl A, Lindgren G, Olsson J (1986) A package for the statistical analysis of visual fields. Doc Ophthalmol Proc Ser 49:153–168
Katz J, Congdon N, Friedman DS (1999) Methodological variations in estimating apparent progressive visual field loss in clinical trials of glaucoma treatment. Arch Ophthalmol 117:1137–1142
Krakau CE (1985) A statistical trap in the evaluation of visual field decay. Acta Ophthalmol Suppl 173:19–21
Lee AC, Sample PA, Blumenthal EZ, Berry C, Zangwill L, Weinreb RN (2002) Infrequent confirmation of visual field progression. Ophthalmology 109:1059–1065
Leske MC, Heijl A, Hyman L, Bengtsson B, EMGT group (1999) Early manifest glaucoma trial: design and baseline data. Ophthalmology 106:2144–2153
Musch DC, Lichter PR, Guire KE, Standardi CL (1999) The collaborative initial glaucoma treatment study: study design, methods, and baseline characteristics of enrolled patients. Ophthalmology 106:653–662
Smith SD, Katz J, Quigley HA (1996) Analysis of progressive change in automated visual fields in glaucoma. Invest Ophthalmol Vis Sci 37:1419–1428
Spry PGD, Johnson CA (2002) Identification of progressive glaucomatous visual field loss. Surv Ophthalmol 47:158–173
Vesti E, Johnson CA, Chauhan BC (2003) Comparison of different methods for detecting glaucomatous visual field progression. Invest Ophthalmol Vis Sci 44:3873–3879
Viswanathan AC, Hitchings RA, Fitzke FW (1997) How often do patients need visual field tests? Graefes Arch Clin Exp Ophthalmol 235:563–568
Acknowledgements
This research was supported by the Dutch Health Care Insurance Council (CVZ) through the Department of Medical Technology Assessment (MTA) of the University Hospital Groningen, the Netherlands.
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Jansonius, N.M. Bayes’ theorem applied to perimetric progression detection in glaucoma: from specificity to positive predictive value. Graefe's Arch Clin Exp Ophthalmol 243, 433–437 (2005). https://doi.org/10.1007/s00417-004-1065-x
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DOI: https://doi.org/10.1007/s00417-004-1065-x