[The influence on the static visual field of peripapillary chorioretinal atrophy--relation to axial length]

To investigate the influence of axial length on white-on-white (W-on-W) perimetry and blue-on-yellow (B-on-Y) perimetry in myopic subjects according to the presence or absence of peripapillary chorioretinal atrophy (PPA).

Both B-on-Y and W-on-W perimetry were performed on 64 normal volunteers whose fundus photography was clear, and the presence or absence of PPA was distinct. We divided the 64 normal volunteers into a PPA group and a no-PPA group, and investigated the influence of axial length on both types of perimetry.

As axial length extended in all cases and in the PPA group, mean deviation (MD) decreased significantly in both B-on-Y and W-on-W perimetry. There was no significant difference in the no-PPA group. In the PPA group, the retinal sensitivity decreased significantly at 22 test points in B-on-Y, as axial length extended; and this decrease occurred at 12 test points in W-on-W perimetry. These points were located mainly around the Mariotte blind spot, central points, and the area of Bjerrum. In the no-PPA group, the retinal sensitivity decreased significantly at only two test points in B-on-Y perimetry, but no decrease occurred at these test points in W-on-W perimetry.

We should consider the presence of PPA and the influence of axial length in the interpretation of the results of W-on-W and B-on-Y perimetry.