Screening for glaucoma using GDx-VCC in a population with ≥1 risk factors

Area of Science:

• Ophthalmology
• Medical Diagnostics
• Public Health

Background:

• Glaucoma is a leading cause of irreversible blindness worldwide.
• Early detection through screening is crucial for managing glaucoma and preventing vision loss.
• The GDx-VCC is a non-invasive device used for assessing retinal nerve fiber layer (RNFL) thickness, a key indicator of glaucoma.

Purpose of the Study:

• To evaluate the diagnostic accuracy of the GDx-VCC for screening glaucoma in individuals with at least one risk factor.
• To determine the sensitivity, specificity, and predictive values of the GDx-VCC in a high-risk population.

Main Methods:

• A cross-sectional study design was employed to assess the GDx-VCC's performance.
• Two hundred forty-seven community volunteers with glaucoma risk factors participated.
• Retinal nerve fiber layer (RNFL) thickness was measured using GDx-VCC, with glaucoma classification based on ophthalmologic examination and frequency doubling perimetry.

Main Results:

• Data from 219 eyes were analyzed after exclusions for poor scan quality or missing data.
• The nerve fiber indicator parameter, with a cutoff of 35, demonstrated 75% sensitivity and 95% specificity.
• Positive predictive value was 25%, and negative predictive value was 99%, with a positive likelihood ratio of 16.

Conclusions:

• The GDx-VCC exhibits inadequate sensitivity for the effective screening of definitive glaucoma.
• While specificity is high, the low sensitivity limits its utility as a standalone screening tool for glaucoma detection in at-risk individuals.