[Perimetry with a glaucoma-specific test grid. A clinical study with the GG program].

UNLABELLED

The GG program pattern of the Humphrey Field Analyzer includes the 76 test points of the 30-2 program and an additional 52 test points in a glaucoma-specific distribution. In 18 test points in the nasal step area beyond 30 degrees the threshold is also determined. The findings obtained with the GG program and the 30-2 program were investigated by means of three questions: (1) Do the additional test points increase the sensitivity in ocular hypertension and glaucoma in stage I? For this purpose 41 eyes of 41 patients were examined. (2) Is the new grid useful for the determination of form and size of scotomas? For this purpose 46 eyes of 46 patients were examined. (3) What information is gained from a new asymmetry index, the glaucoma hemifield index (GHI), evaluated on the retinal threshold sensitivity of the GG program grid? To evaluate the information gained, the GHI of the test points in program 30-2 was compared to the GHI of the GG program in 11 eyes of 11 healthy persons, 21 eyes of 21 patients with ocular hypertension, and 32 eyes of 32 patients with primary open-angle glaucoma, stage I and II.

RESULTS

(1) In ocular hypertension and glaucoma stage I, the higher grid density of the GG program leads to a higher sensitivity in comparison to program 30-2. (2) In the 46 eyes with scotomas in stages II-IV, the condensed grid allowed better assessment of form and size of them. Ninety-one percent of the eyes with glaucoma stage II-IV showed nasal scotomas out of 30 degrees excentricity, which were now detected with the GG program. (3) The GHI of program 30-2 and the GG program showed no significant difference in retinal threshold sensitivity in glaucoma stage I. The asymmetry of the visual field loss in glaucoma stage II with localized scotomas can be detected significantly better with the GHI of the GG program. At the beginning of visual field loss with diffuse sensitivity loss, the grid density of program 30-2 seems to be sufficient. In stage II with localized scotomas, the higher grid density of the GG program yield more information for the detection of hemifield asymmetries. After examination with the 30-2 program it seems to be useful to examine the 52 additional test points and combine these two with the print-out from the GG program.