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Analysis of progressive change in automated visual fields in glaucoma
S D Smith1, J Katz, H A Quigley
1Dana Center for Preventive Ophthalmology, Wilmer Ophthalmological Institute, Johns Hopkins University, Baltimore, Maryland, USA.
Investigative Ophthalmology & Visual Science
|June 1, 1996
Summary
Fewer than 30% of glaucoma patients showed visual field loss progression over 7 years. Statistically significant progression rates ranged from 1-5 dB/year, requiring ~5 years of annual testing for detection.
Area of Science:
- Ophthalmology
- Medical Imaging
- Data Analysis
Background:
- Glaucoma is a leading cause of irreversible blindness worldwide.
- Early detection and monitoring of visual field loss are crucial for managing glaucoma.
- Automated perimetric visual field testing provides quantitative data for assessing disease progression.
Purpose of the Study:
- To detect and quantify the rate of visual field loss progression in glaucoma patients.
- To evaluate the long-term effectiveness of automated perimetric visual field testing in glaucoma monitoring.
- To establish criteria for classifying glaucoma patients as progressive or stable.
Main Methods:
- Utilized automated visual field data from 191 glaucoma patients with at least 7 tests over 4.5 years.
- Employed univariate linear regression to analyze Mean Deviation (MD), Corrected Pattern Standard Deviation (CPSD), Glaucoma Hemifield Test (GHT) clusters, and individual test locations.
- Classified subjects as progressive or stable based on the statistical significance and slope of regression parameters, with adjusted P values to maintain a 5% type 1 error rate.
Main Results:
- Over a mean follow-up of 7.1 years, 12.6% of subjects showed MD progression and 14.1% showed CPSD progression.
- 18.3% had progressive GHT clusters, and 18.8% had progressive individual test locations.
- Overall, 27.2% of subjects were classified as progressive based on at least one criterion.
Conclusions:
- Less than one-third of glaucoma patients exhibited statistically significant visual field progression over an average of 7.1 years.
- Confirmed progression rates varied from approximately 1 to 5 dB/year, influenced by testing frequency, data variability, and assessment parameters.
- A minimum of 5 years of annual perimetry is recommended for reliable detection of significant visual field changes using linear regression.