[Topography of early glaucomatous visual field defects in computerized perimetry]

A total of 301 visual fields of 215 glaucoma patients exhibiting early glaucomatous field loss up to Stage II according to Aulhorn were investigated to determine the frequency distribution of absolute and relative defects at the 73 test points of Program 31 of the Octopus computer perimeter. The following results were obtained: (1) The frequency of absolute and relative defects was higher in the upper half of the visual field; (2) The frequency of both absolute and relative defects increased from 6 to 30 degrees eccentricity in the upper visual field, predominantly in the upper nasal quadrant, whereas in the temporal lower quadrant there were less absolute defects but equally frequent relative defects; (3) Defects in the nasal quadrant and above the horizontal meridian are most frequent (between 18 and 30 degrees absolute, between 12 and 30 degrees relative), while temporally of the blind spot and below the horizontal meridian they are quite rare; (4) In the upper half of the field, defects are closer to the fixation point and blind spot; the area between blind spot and macula largely free of defects. --In 71 eyes of 69 patients a similar frequency distribution was found with the Competer computer perimeter (test field 15-20 degrees eccentricity) giving good correlation with the Octopus results. --In 301 eyes of 215 patients with early glaucomatous defects the four test points in the region of the blind spot were evaluated and compared with the results of 121 eyes of 71 patients with ocular hypertension and no field changes. It appears highly probable that an increase in the size of the blind spot is associated with the incidence of field defects. --The distribution of early glaucomatous field defects in 214 eyes revealed a combination of paracentral scotomata with peripheral defects in 75.2%, exclusively peripheral scotomata in 19.6% and exclusively paracentral scotomata in 5.1%. The significance of the results with regard to the pathophysiology of glaucomatous visual field loss is discussed.