Background and objective: To analyze changes in the optic disc topography after filtration surgery.
Patients and methods: Laser scanning tomography was performed in 10 eyes of 9 patients (mean age 65.6 +/- 8.1 years; age range 55 to 75 years) after a mean follow-up of 3.7 months, and in 8 eyes of 7 patients (mean age 63.1 +/- 7.6 years; age range 55 to 75 years) after a mean follow-up of 13.1 months.
Results: Preoperatively, the mean intraocular pressure (IOP) was 24.4 +/- 6.9 mm Hg with maximal medication. Postoperatively at 3.7 months it was 11.0 +/- 2.2 mm Hg, and at l2.1 months it was l3.6 +/- 2.8 mm Hg. An initial reduction in IOP of more than 30 percent at 3.7 months was achieved without medication in all but 1 eye. After 12.1 months, an IOP reduction of more than 30 percent was achieved in 6 of 8 eyes (1 with medication), while 2 eyes had IOP reductions of less than 15 percent (< or = 3 mm Hg) despite medication. In the 6 eyes, the optic disc cup volume showed a decrease of more than 30 percent, while the 2 eyes without marked IOP reductions had slight increases in cup volume. Of the 2 eyes without marked decreases in cup size, 1 had normal-tension glaucoma and 1 experienced an increase in IOP of more than 25 mm Hg during the first postoperative week.
Conclusion: The postoperative IOP should be kept low enough to permit reversal of optic disc changes.