Specification of progression in glaucomatous visual field loss, applying locally condensed stimulus arrangements.

PURPOSE

The goal of this work was to (i) determine patterns of progression in glaucomatous visual field loss, (ii) compare the detection rate of progression between locally condensed stimulus arrangements and conventional 6 degrees x 6 degrees grid, and (iii) assess the individual frequency distribution of test locations exhibiting a local event (i.e., an abrupt local deterioration of differential luminance sensitivity (DLS) by more than -10 dB between any two examinations).

METHODS

The visual function of 41 glaucomatous eyes of 41 patients (16 females, 25 males, 37 to 75 years old) was examined with automated static perimetry (Tuebingen Computer Campimeter or Octopus 101-Perimeter). Stimuli were added to locally enhance the spatial resolution in suspicious regions of the visual field. The minimum follow-up was four subsequent sessions with a minimum of 2-month (median 6-month) intervals between each session. Progression was identified using a modified pointwise linear regression (PLR) method and a modified Katz criterion. The presence of events was assessed in all progressive visual fields.

RESULTS

Eleven eyes (27%) showed progression over the study period (median 2.5 years, range 1.3-8.6 years). Six (55%) of these had combined progression in depth and size and five eyes (45%) progressed in depth only. Progression in size conformed always to the nerve fiber course. Seven out of 11 (64%) of the progressive scotomata detected by spatially condensed grids would have been missed by the conventional 6 degrees x 6 degrees grid. At least one event occurred in 64% of all progressive eyes. Five of 11 (46%) progressive eyes showed a cluster of events.

CONCLUSIONS

The most common pattern of progression in glaucomatous visual fields is combined progression in depth and size of an existing scotoma. Applying individually condensed test grids remarkably enhances the detection rate of glaucomatous visual field deterioration (at the expense of an increased examination time) compared to conventional stimulus arrangements.