Abstract
Purpose: :
To evaluate long-term intraocular pressure (IOP) fluctuation in patients with moderate to advanced glaucoma after a primary trabeculectomy and compare it with patients treated with topical medical therapy.
Methods: :
In a retrospective longitudinal case-control study, data was collected for 189 eyes (152 patients) that have undergone a primary trabeculectomy by the same surgeon and 162 eyes (101 patients) with similar severity of glaucoma but treated with topical hypotensive medication. Patients with primary open angle, pseudoexfoliative, normal tension and pigmentary glaucoma were included. Follow-up was > 3 years and > 8 IOP measurements per patient were required. Long-term fluctuation was defined as the standard deviation (SD) of all IOP measurements.
Results: :
In the trabeculectomy group (189 eyes) mean age was 68.3 years (range 41 to 90) and 61.9 % were female. In the medication group (162 eyes) mean age was 69.2 years (range 37 to 85) and 61.7 % were female. Follow-up was 6.05 ± 2.17 years and the number of visits was 17.92 ± 9.26. In the trabeculectomy group average mean deviation (MD) of visual fields at the beginning was -9.6 while in the medication group MD was -8.47 (p=0.72, Mann-Whitney test). The number of medications was 0.55 ± 0.83 in the trabeculectomy group and 1.75 ± 0.86 for the medication group (p< 0.001). Mean IOP was 10.73 ± 3.53 in the trabeculectomy group and 13.60 ± 2.92 in the medication group (p<0.001). Fluctuation of IOP was 2.48 ± 1.23 in trabeculectomy and 2.35 ± 1.02 in the medication group (p=0.48). A correlation between the mean IOP and the fluctuation was detected in the trabeculectomy (p<0.001) and in the medication group (p<0.001). Once controlled for mean IOP there was no statistically significant difference in fluctuation between the two groups (p=0.11). We had a power of 80% to detect a mean difference in fluctuation of 0.20 mmHg between the two groups.
Conclusions: :
Although mean IOP was significantly lower in the trabeculectomy group, we did not find a statistically or clinically significant difference of IOP fluctuation between the trabeculectomy and the medication group.
Keywords: intraocular pressure