[Frequency doubling perimetry in terminal visual field defects].

Area of Science:

• Ophthalmology
• Visual Neuroscience
• Medical Technology

Background:

• Glaucoma is a leading cause of irreversible blindness worldwide.
• End-stage glaucomatous visual field defects present significant challenges in accurate assessment.
• Traditional perimetric strategies may have limitations in evaluating severe visual field loss.

Purpose of the Study:

• To evaluate the efficacy of Frequency Doubling Technology (FDT) perimetry in assessing end-stage glaucomatous visual field defects.
• To compare FDT (C-20 threshold test) with the standard 24-2 SITA test in patients with advanced glaucoma.
• To determine if FDT offers advantages in sensitivity, speed, and topographic correlation.

Main Methods:

• A cohort of 22 patients with end-stage visual field defects (defined by 24-2 SITA criteria) underwent FDT (C-20 threshold test).
• Key metrics including sensitivity, percentage of non-abolished points, test duration, and global indices (Mean Defect, Pattern Standard Deviation) were compared.
• Topographic correlation was assessed using the Kappa agreement test.

Main Results:

• FDT demonstrated 100% sensitivity in detecting visual field defects.
• The C-20 test identified 13.7% more points with sensitivity > 0 dB compared to the 24-2 test (P=0.002).
• FDT testing was significantly faster (2.5 minutes less, P<0.001) and showed a better Mean Defect (11.48 dB better, P=0.000).
• Excellent topographic agreement was observed between FDT and 24-2 SITA (Kappa=0.911, P<0.001), particularly in the inferotemporal quadrant.

Conclusions:

• Frequency Doubling Technology (FDT) is a more capable perimetric strategy than the 24-2 SITA test for evaluating end-stage glaucomatous visual field defects.
• FDT offers the significant advantage of reduced testing time.
• Further research is warranted to confirm the reproducibility of FDT in severe glaucoma cases.