Long-term perimetric variability in patients with different stages of glaucoma

Purpose:To provide mean values and 95% confidence intervals (CI) for perimetric long-term variability (LTV) of glaucomatous patients with different stages of the disease. Methods:We reviewed the perimetric data of 49 glaucoma patients (age, F/M) who underwent a mean of 4 visual fields (Humphrey 30-2, white-on-white program) over a follow-up of 24 months. All patients were clinically stable (during the study, no changes occurred in: medical regimen, perimetric indices and clusters of abnormal points, optic nerve head appearance and mean intraocular pressure). The stage of the disease was classified according to the Glaucoma Staging System 2 (GSS2). LTV was calculated as the mean of the square roots of the point-to-point variances throughout repetitions. For each stage, mean LTV, standard deviation, and confidence intervals were given. Results:The main results of the study are summarized in the Table. Patients at stage 0 had lower LTF compared to the other stages (P<0.05), while LTF was significantly higher in stage 4 compared to all the other stages (P<0.01). Conclusions:LTF significantly varied between stages of the disease at GGS2; a trough in fluctuation was found at stage 0, while it peaked at stage 4.