Reproducibility of measurements by laser scanning tomography in eyes before and after pilocarpine treatment.

We measured the optic disc topography of ten eyes from ten normal, healthy volunteers before and 1 h after pilocarpine treatment, using the Heidelberg Retina Tomograph. The mean age of the volunteers was 26.4 years, and the mean pupil diameter before and after pilocarpine treatment was 5.5 mm and 3.2 mm, respectively. We collected a series of five to ten consecutive topographic images of the optic disc for each eye, before and after treatment. The mean coefficients of variation of the measurements for the three randomly selected topographic images before pilocarpine treatment were 7.28% (1.25-15.15%) for cup volume and 7.33% (1.44-15.24%) for mean depth inside the cup margin. After treatment, the means were 12.25% (3.24-21.80%) and 12.88% (0.66-21.71%), respectively. Statistically significant differences were observed (P < 0.05) between the pre- and post-treatment coefficients of variation. These results suggest that care should be taken to evaluate the disc changes in eyes treated with pilocarpine.