Objective: Reevaluation of the relationship between short wavelength automated perimetry (SWAP), standard achromatic perimetry (SAP), and frequency doubling technology (FDT) in glaucoma and ocular hypertensive patients and in glaucoma suspects.
Design: Prospective comparative observational study.
Participants: Four age-matched groups were evaluated (42 patients with early to moderate glaucoma, 34 ocular hypertensives, 22 glaucoma suspects, and 25 normal controls) using SAP, SWAP, and FDT.
Intervention: All participants underwent full clinical ophthalmologic evaluation followed by SWAP, SAP, and FDT perimetry within a period of not more than 3 months. Mean defect (MD), pattern standard deviation (PSD), visual field (VF) indices, and the percentage of depressed visual field points with P value <5% and <1% in the pattern deviation plot were evaluated.
Main outcome measures: For each of the four study groups, the MD, PSD, and the percentage of abnormal points significantly depressed <5% and <1% were compared for the three VF testing modalities.
Results: In the glaucoma group, the mean percentage of the total number of abnormal points in SWAP was significantly less than abnormal points in SAP and FDT, both for 5% (P values were 0.0001 and 0.0001, respectively) and 1% (P values were 0.0001 and 0.0001, respectively). The same applied to the ocular hypertensives group. However, in the suspects group, no significant difference was detected. In normal controls, the abnormal points in SWAP were significantly lower than those in SAP for 5% (P value was 0.01) and 1% (P value was 0.05). FDT detected significantly larger defects (percentage of points <5%) than SAP in ocular hypertensives and suspects (P values were 0.01 and 0.004, respectively).
Conclusions: SWAP in its existing condition is markedly less efficient than either SAP or FDT in detecting VF defects, especially in glaucoma patients and ocular hypertensives (defects detected with SWAP are less than both SAP and FDT). Defects detected with FDT are equivalent to SAP and sometimes larger, especially in ocular hypertensives and glaucoma suspects; this makes it a useful tool for picking up early glaucomatous defects in populations at risk.