THE INFLUENCE OF AGE-RELATED CATARACT ON BLUE-ON-YELLOW PERIMETRY

Purpose. The influence of cataract on the blue-on-yellow visual field is unknown. The aim of the study was to compare the effect of age-rela ted cataract on the normal blue-on-yellow (B-Y), yellow-on-yellow (Y-Y ) and white-on-white (W-W) visual field. Methods. Forty normal subject s (age range, 60 to 81 years) randomly performed BY, Y-Y, and W-W peri metry using a modified Humphrey Field Analyser 640 (HFA) (Program 24-2 ). Twenty age-matched patients with cataract underwent the same testin g paradigm. Cataract was classified using the LOCS II system. Ocular m edia absorption was measured with the HFA by determining the differenc e in scotopic sensitivity to 410-nm and 560-nm stimuli. Forward light scatter was measured by the direct compensation technique of van den B erg. Unweighted mean deviation (MD), short-term fluctuation, and corre cted pattern standard deviation indices were calculated for each patie nt with cataract for each of the three stimulus combinations. Results. Cataract produced an adverse effect on the MD (i.e., a more negative MD) in all patients for each of the three stimulus combinations. The m agnitude depended on the degree and type of cataract and was highly co rrelated with forward light scatter. The attenuation in sensitivity wa s greatest for the B-Y and W-W stimulus combinations; the B-Y field wa s preferentially affected by posterior subcapsular cataract and the W- W field by anterior cortical cataract. Conclusions. Cataract predomina ntly causes a general reduction in B-Y sensitivity. Caution therefore needs to be exercised in the interpretation of the B-Y visual field in patients in whom glaucoma and cataract coexist.