Purpose: To evaluate the potential of frequency doubling technology for detecting early glaucomatous damage.
Patients and methods: Forty-nine eyes of 49 patients with open-angle glaucoma with visual field defects only in one hemifield according to the Humphrey Field Analyzer 30-2 program were included. Forty-five healthy patients were also included as control subjects. In each patient, frequency doubling technology with the threshold N-30 program and optic disc analysis using the Heidelberg Retina Tomograph was performed. Frequency doubling technology test results and the Humphrey Field Analyzer test results were compared. Optic disc parameters corresponding to the hemifield designated intact by the Humphrey Field Analyzer were compared between the eyes in which the hemifield was normal by frequency doubling technology and those in which the hemifield was abnormal.
Results: Forty-one percent of the 49 hemifields designated intact by the Humphrey Field Analyzer were abnormal based on frequency doubling technology, whereas 98% of the 49 hemifields designated defective by the Humphrey Field Analyzer were abnormal and 12% of the 90 hemifields designated intact by the Humphrey Field Analyzer were abnormal in healthy patients. The percentage of the hemifields designated abnormal by frequency doubling technology was significantly higher than that in healthy patients (P < 0.001). The rim volume was significantly smaller in eyes with abnormal results based on frequency doubling technology than in eyes with normal results (P < 0.05, paired t test, with Bonferroni correction for multiple comparison).
Conclusion: Frequency doubling technology can detect glaucomatous damage earlier than conventional static perimetry can.