A comparison of four projection perimeters

Area of Science:

• Ophthalmology
• Visual Science
• Medical Devices

Background:

• Perimetry is crucial for diagnosing visual field defects.
• Standardized specifications for perimeters suggest comparable performance.
• Variations in instrument performance can impact clinical diagnosis.

Purpose of the Study:

• To compare the performance of four projection perimeters: Goldmann, Marco, Topcon, and Rodenstock.
• To identify differences in visual field mapping capabilities among these instruments.
• To investigate the reasons behind observed performance variations.

Main Methods:

• Thirty eyes were subjected to visual field testing using all four perimeters.
• Standardized targets and dome specifications were used initially.
• Subsequent analysis examined actual target size and luminance for each machine.

Main Results:

• The Rodenstock perimeter frequently failed to map central fields or detect defects.
• The Goldmann perimeter demonstrated the highest sensitivity and definition in mapping scotomata.
• Topcon and Marco perimeters showed intermediate sensitivity, with Topcon slightly outperforming Marco.

Conclusions:

• Despite identical specifications, significant variations in target size and luminance exist among perimeters.
• These variations directly impact the ability to accurately plot visual fields and detect defects.
• The Goldmann perimeter offers superior performance for visual field assessment compared to the tested alternatives.