Objective: To assess the value of short-wavelength automated perimetry in the diagnosis of early glaucoma.

Methods: Fourty-six eyes of 36 patients with early open angle glaucoma and a group of 38 normal persons (46 eyes) were examined both by the standard automated (white-on-white, W/W) perimeter and short-wavelength (blue-on-yellow, B/Y) perimeter. The age and sex in two groups were matched. The program 24 - 2 was performed on both B/Y and W/W fields in two groups. The mean light sensitivity (MS) of the central 25 degrees and in each quadrant from two perimetries was calculated and analyzed statistically by Student t-test and ASNOV.

Results: The difference of MS in central 25 degrees between two perimetries in normal group was 1.63 dB which showed a statistical significance of difference (t = 3.57, P < 0.001). MS was significantly higher in W/W than that in B/Y either in central 25 degrees or in each corresponding quadrant (t = 3.45, P < 0.001). The MS difference between them was more than 2.87 dB and the MS average difference of the corresponding quadrant was more than 2.5 dB (t = 4.57, 3.42, P < 0.001). MS from four quadrants were different from one other. The lowest MS was in the superior temporal, the highest MS was in inferior nasal quadrant; the superior nasal and inferior temporal were in between them. The defects in B/Y perimetry were larger and deeper than that in W/W perimetry. The result of corrected deviation points (u = 3.22, P < 0.05) was used to account the defected testing points, which showed the defected points were significantly more in B/Y perimetry than that in W/W perimetry (chi(2) = 226.72, P < 0.001). The data revealed that the defected testing points from B/Y perimetry were 2.6 times of that from W/W perimetry. In the early glaucoma group, the positive rate in the abnormal visual field from B/Y perimetry was 87% (40/46) and that from W/W perimetry, 67% (31/46).

Conclusions: A good coincidence is demonstrated between B/Y and W/W perimetries both in normal and in early open angle glaucoma groups. B/Y perimetry is more sensitive than W/W perimetry in detecting early glaucomatous visual field defects. The positive rate is higher and the defects are larger and deeper in B/Y perimetry than that in W/W perimetry. Therefore, B/Y perimetry can detect glaucoma defects earlier. It is suggested that B/Y perimetry be applied in diagnosing early glaucoma.