Performance of the 24-2-5 frequency doubling technology screening test: a prospective case study

Area of Science:

• Ophthalmology
• Optometry
• Medical Technology

Background:

• Glaucoma screening is crucial for early detection and prevention of vision loss.
• Frequency Doubling Technology (FDT) perimetry is a common method for visual field testing in glaucoma.
• Established FDT screening tests require evaluation against newer protocols.

Purpose of the Study:

• To compare the performance of the FDT 24-2-5 screening test against the N-30-5 FDT screening test.
• To assess discriminatory power, reliability, and test duration for glaucoma detection.

Main Methods:

• A prospective study involving individuals referred for possible glaucoma.
• Testing with FDT 24-2-5 and N-30-5 screening tests using Humphrey Matrix perimeter.
• Standard clinical examination and comparison of sensitivity, specificity, and reliability.

Main Results:

• Both tests showed high discriminatory power for glaucoma detection (AUC 0.87 for N-30-5, 0.92 for 24-2-5).
• The 24-2-5 test had higher sensitivity (83%) but lower specificity (75%) than the N-30-5 (78% sensitivity, 85% specificity).
• The 24-2-5 test was significantly longer (111s vs 39s) and yielded more unreliable results (36% vs 9%).

Conclusions:

• Minimal differences in discriminatory power were observed between the FDT 24-2-5 and N-30-5 screening tests.
• The N-30-5 test demonstrated better reliability and a shorter test duration compared to the 24-2-5.
• Both FDT screening tests are effective in detecting individuals with glaucoma.