[Changes in perimetric defects in chronic open-angle glaucoma studied by automated perimetry (Octopus)]

Area of Science:

• Ophthalmology
• Visual Science
• Medical Technology

Background:

• Chronic open-angle glaucoma (COAG) is a progressive optic neuropathy.
• Accurate monitoring of visual field changes is crucial for managing COAG.
• Existing methods may have limitations in detecting subtle paracentral visual field degradation.

Purpose of the Study:

• To evaluate the utility of a novel "global value" parameter derived from Octopus perimetry for monitoring visual field changes in COAG patients.
• To establish a reliable numerical parameter for assessing paracentral visual field status.
• To analyze the variability and significance of changes in this "global value" over time.

Main Methods:

• Utilized the Octopus automatic perimeter on 90 patients with COAG.
• Calculated a "global value" using 62 specific test points from program 33, excluding Mariotte's zone and central 10 degrees.
• Performed statistical analysis on "global value" variations between successive examinations.

Main Results:

• A significant improvement in "global value" was observed between the first and second tests.
• This improvement phenomenon disappeared in subsequent tests.
• A degradation of 1 dB between the first two tests and 3 dB in later tests was identified as significant for visual field loss (1% error).

Conclusions:

• The "global value" serves as an effective numerical parameter for monitoring paracentral visual fields in COAG.
• Initial "global value" improvements may be influenced by patient learning or test experience.
• Established thresholds (1 dB/3 dB) for "global value" degradation indicate significant visual field loss in COAG patients.