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Visual-field defects in well-defined retinal lesions using Humphrey and Dicon perimeters.

BACKGROUND
This study was undertaken to correlate field defects in patients having well-defined retinal lesions within the central 30 degrees using Humphrey and Dicon perimetry standard threshold programs and to compare these results against the standard of fundus photography.


METHODS
Eleven eyes of 11 patients had various well-defined retinal lesions. Ten of those subjects had best-corrected visual acuity of 20/25 or better. Subjects had either one previous field or no previous experience with any automated perimeter and were tested using either the 30-2 Full Threshold or SITA Standard program of the Humphrey Field Analyzer (HFA) Model 750 and the Central Grid Threshold program (#9) (a full-threshold program) of the Dicon LD-400 perimeter. Defects were scored and compared with fundus photographs scored by an independent observer.


RESULTS
Significant high positive correlation coefficients were found between Humphrey, Dicon, and fundus photography, for mean number of significant field defects and for mean deviations. There were no significant differences between the mean scores, mean deviations, or fixation loss percentages. The time the patient occupied a perimeter was 56% less with the Dicon perimeter than with the Humphrey perimeter when the Full Threshold test was used and 8% less when the SITA Standard was used.


CONCLUSION
In this study of patients with well-defined retinal lesions, both Humphrey and Dicon Central Threshold field programs exhibited an equally high positive correlation in mapping scotomas of expected size and depth when compared with fundus photography, with no significant difference in fixation loss frequency. However, the total testing time was less with Dicon perimetry than with Humphrey perimetry.