Abstract
Purpose: :
To evaluate the performance of Frequency Doubling Perimetry (FDP–Matrix) compared to Short Wave Length Automated Perimetry (SWAP) for the detection of early glaucomatous visual loss.
Methods: :
Forty eight patients (48 eyes) with evidence of glaucomatous optic nerve head damage according to clinical evaluation but with normal visual field results according to Standard Acromatic Perimetry and forty normal subjects (40 eyes) evaluated as normal by clinical examination were recruited for the study. FDP–Matrix and SWAP measurements were made on one eye of each patient within an interval six months or less. The mean defect (MD), pattern standard deviation (PSD), and the average number of abnormal points in the pattern deviation plot from both visual field tests were compared.
Results: :
The average MDs (±SD) of FDP–Matrix and SWAP were –1.091 (± 4.15) dB and 0.281 (± 4.24) dB respectively (r=0.55; p < 0.01). The mean durations (± SD) of the FDP–Matrix and SWAP tests were 5.1 (± 0.59) and 7.0 (± 1.38) minutes, respectively. There was no significant difference between the two visual field tests for the average number of Pattern Deviation depressed visual field points at the 5% level (p = 0.98) and at the 1% level (p = 0.62). The pattern of the defects agreed in thirty six eyes (75%). In addition, FDP–Matrix defects were more extensive (larger or deeper) than SWAP in thirty eyes (62%).
Conclusions: :
FDP–Matrix and SWAP are similar in their ability to detect early glaucomatous visual field loss. More extensive defects found in FDP–Matrix may reveal visual field loss earlier than SWAP. Long term follow–up of visual field progression will be needed to confirm this.
Keywords: visual fields • perimetry