Mean deviation fluctuation in eyes with stable Humphrey 24-2 visual fields.

Area of Science:

• Ophthalmology
• Optometry
• Clinical Neuroscience

Background:

• Glaucoma is a leading cause of irreversible blindness worldwide.
• Accurate diagnosis of glaucomatous progression is crucial for timely intervention.
• Visual field testing is a key method for monitoring glaucoma, but understanding expected fluctuations is vital.

Purpose of the Study:

• To establish expected fluctuations in Mean Deviation (MD) scores for stable visual field defects.
• To provide clinicians with a tool for diagnosing glaucomatous progression more accurately.
• To correlate visual field defect severity with the expected range of MD score variation.

Main Methods:

• Analysis of 1010 Humphrey 24-2 visual fields from 202 patients with stable glaucoma over at least 3 years.
• Scoring of visual fields using the Advanced Glaucoma Intervention Study (AGIS) system.
• Calculation of 99% confidence intervals (CI) for MD score fluctuations across different grades of visual field defects.

Main Results:

• The 99% CI for MD score fluctuations ranged from 0.3 dB (no defect) to 1.3 dB (end-stage defects).
• A strong positive correlation (r=0.7, P=0.0003) was observed between the CI and the grade of visual field defect.
• Minimal fluctuation (P=0.96) was found across all defect stages in stable eyes.

Conclusions:

• Clinicians should expect minimal MD score fluctuation in reliable visual fields of stable eyes.
• An increase in MD beyond the established 99% CI may indicate glaucomatous progression.
• Visual field test reliability indices are paramount for accurate glaucoma assessment.