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Quantifying effects of retinal illuminance on frequency doubling perimetry
William H Swanson1, Mitchell W Dul, Susan E Fischer
1Glaucoma Institute, SUNY State College of Optometry, New York, New York 10036, USA. bswanson@sunyopt.edu
Investigative Ophthalmology & Visual Science
|December 30, 2004
Summary
Retinal illuminance significantly impacts frequency doubling technology (FDT) perimetry results. A new model quantifies these effects, aiding in accurate FDT perimetry interpretation under varying conditions.
Area of Science:
- Ophthalmology
- Visual Neuroscience
- Medical Technology
Background:
- Frequency Doubling Technology (FDT) perimetry is a visual field test.
- Variations in retinal illuminance can affect perimetry outcomes.
- Understanding these effects is crucial for accurate diagnosis.
Purpose of the Study:
- To measure and quantify the impact of changing retinal illuminance on FDT perimetry.
- To develop a model predicting these illuminance-related effects.
Main Methods:
- Two studies were conducted using a Zeiss-Humphrey/Welch Allyn FDT perimeter.
- Study 1 assessed adaptation to varying illuminance levels using neutral density filters.
- Study 2 evaluated the effect of reduced illuminance due to pupillary miosis.
Main Results:
- A 1.6 log unit change in retinal illuminance altered Mean Defect (MD) by up to 10 dB.
- A quantitative adaptation model explained 69% of the variance in MD changes.
- Model accuracy was consistent regardless of the magnitude of change.
Conclusions:
- Retinal illuminance variations significantly influence FDT perimetry results.
- A quantitative adaptation model can estimate the impact of pupil size and lens density.
- This model offers guidelines for more reliable FDT perimetry interpretation.
