Correlation of blue-on-yellow visual fields with scanning confocal laser optic disc measurements

Visual field defects and changes in the optic nerve head are signs of glaucoma. It has been shown that blue-on-yellow (B-Y) perimetry can reveal visual field defects earlier and shows them larger than does white-on-white (W-W) perimetry. The Heidelberg retina tomograph (HRT) can produce three-dimensional images of the optic disc. The aim of this study was to find out how B-Y perimetry results correlate with optic disc parameters in comparison with W-W perimetry results.

One randomly chosen eye was evaluated in each of 40 normal subjects and 37 patients with ocular hypertension and different stages of glaucoma. B-Y and W-W visual fields (program 30-2) were obtained with a Humphrey perimeter. B-Y perimetry results were adjusted for the patient's age and lens transmission index measured with a lens fluorometer. The B-Y visual field adjusted mean deviation (MD) was calculated as the difference between the measured and expected mean sensitivity values, predicted by the regression model fitted in normal subjects. The HRT with software version 1.11 was used to acquire and evaluate topographic measurements of the optic disc.

The cup shape measure showed strongest correlation with the MD of both the B-Y and W-W visual fields. The multiple correlation coefficients from quadratic regression were 0.65 for both visual fields. Except for peripapillary retinal nerve fiber layer measurements, the statistically significant correlations of the B-Y visual field indexes with other HRT parameters were equal to or better than those of W-W perimetry.

B-Y perimetry MDs are well correlated with optic nerve head parameters measured with the HRT. In early stages of glaucoma, most HRT variables were better correlated with the B-Y MD than with the W-W MD.