VISUAL-FIELD DEFICITS IN EARLY AGE-RELATED MACULAR DEGENERATION

Patients with early age-related macular degeneration (AMD) may retain good visual acuity but experience distortion and other qualitative vis ual changes. The purpose of the present study was to determine whether deficits of form recognition, as well as of light sensitivity; were r elated to retinal pigment epithelial (RPE) atrophy and/or drusen. We a ssessed form recognition deficits by the Amsler grid and by a perimetr ic test of letter recognition and sensitivity deficits by the macular threshold test of the Humphrey Field Analyzer in 59 patients with AMD and visual acuities of 20/40 or better. The number of defects on each test was compared with the area of RPE atrophy and with the area of dr usen determined from fundus photographs. Multiple regression analyses based on ordinal data revealed that the number of visual field defects by each test was significantly correlated with the area of atrophy, b ut not with the area of drusen. There was also no significant tendency for a patient with a regional preponderance of drusen to have more im pairment in the corresponding visual field. These results suggest that deficits of form recognition, as well as of sensitivity, in patients with early stages of AMD can be attributed to alteration of photorecep tor function associated with RPE atrophy, but not with drusen.