Importance of Status of Visual Field and Optic Disc*

Factors associated with long-term progression or stability in primary open-angle glaucoma

PURPOSE

To evaluate long-term risk factors for progression or stability in patients with primary open-angle glaucoma.

METHOD

We retrospectively included consecutively reviewed patients who had primary open-angle glaucoma for at least 5 years in this multicenter trial. Historical and clinical factors in these patients were evaluated for their association with stability or progression of the glaucoma.

RESULTS

We included 218 patients in this study; of these, 34 progressed over an average length of follow-up of 45.5 +/- 30.0 months, and 184 were stable over an average of 72.8 +/- 18.3 months. The mean intraocular pressure over the follow-up period for the progressed group was 19.5 +/- 3.8 mm Hg and for the stable group 17. 2 +/- 3.1 mm Hg (P =.001). The average standard deviation of individual intraocular pressures was greater in the progressed group (5.1 mm Hg) than the stable group (3.9 mm Hg, P =.012). Baseline characteristics indicating a greater potential to progress were a larger cup-to-disk ratio (P <.001), a greater number of medications (P =.02), older age (P.007), and worse visual acuity (P =.003). However, no difference was observed in pressure levels that prevented progression in these subpopulations compared with the total sample size.

CONCLUSIONS

This study suggests that lowering the intraocular pressure is important in the treatment of primary open-angle glaucoma to help prevent long-term progression. Lowering the pressure, however, is not uniformly effective in preventing progression. Additionally, risk factors for progression do not further help identify pressure levels that prevent worsening of glaucoma.

Why do some people go blind from glaucoma?

Retrospective analysis of patients blinded by glaucoma has revealed a need to educate patients to the significance of premonitory symptoms, to investigate a higher incidence of blindness from open-angle glaucoma among blacks than whites, and to define the goals of therapy in relation to presenting pathology. Responding to this third need, circumstances of patients followed for 20 to 40 years with extensive documentation relating to open-angle glaucoma were analyzed. Some eyes with normal discs and fields were found to tolerate a tension of 30 mm Hg for many years without need of treatment. But, when abnormalities ranging from early glaucomatous cupping to advanced visual field defects were present on initial evaluation, progressive loss of field tended to occur at lower tensions. It appears that the worse the initial condition of the eye, the lower the tension needs to be to prevent further loss or blindness.