Frequency doubling perimetry in patients with mild and moderate pituitary tumor-associated visual field defects detected by conventional perimetry.
PURPOSE
To test the ability of frequency doubling technology (FDT) perimetry to identify pituitary tumor-associated visual field defects.


METHODS
Twenty-three eyes from patients with pituitary tumor (PT) and 28 normal eyes were studied. Subjects were eligible when presenting with normal visual acuity and mild or moderate temporal field loss in at least one eye on Goldmann and standard automated perimetry (SAP). FDT testing was performed using the C-20-5 screening and the C-20 full-threshold test. The sensitivity and specificity for identification of the field defect were determined and the groups were compared with regard to several parameters. Finally, we compared the ability of FDT and SAP to detect the characteristic pattern of temporal hemianopia/quadrantanopia.


RESULTS
In the screening test, sensitivity ranged from 21.74% to 43.48% while specificity was 100%. In the threshold test, sensitivity ranged from 52.17% to 82.61% (specificities of 85.71% and 60.71%, respectively), according to total deviation analysis, and from 30.43% to 73.91% (specificities of 96.42% and 64.28%, respectively), according to the pattern deviation analysis. Patients with PT presented a significantly higher number of abnormal points in the temporal hemifield. In 12 eyes FDT and SAP were both able to identify the characteristic pattern of visual field defect; in 4 eyes FDT performed better than SAP; in 4 eyes, SAP performed better than FDT, while in 3 neither test was able to determine the pattern of visual field defect correctly.


CONCLUSIONS
Threshold FDT perimetry seems to be a sensitive instrument for identifying abnormality in eyes with chiasmal compression-induced field defects detected on conventional perimetry.