Aim: To evaluate the effects of tolterodine and oxybutynin on visual accommodation, pupillary diameter, intraocular pressure and tear secretion in women with overactive bladder.
Methods: One hundred and four eyes from 52 consecutive female patients (age range: 22-60 years) with a urodynamic diagnosis of overactive bladder were prospectively investigated. Patients with a history of ocular disease or surgery were excluded. The subjects were randomly assigned to one of two groups: Group I received 2 mg tolterodine bid and Group II received 5 mg oxybutynin tid. All patients were evaluated at baseline (day 0) and after 1 month of treatment (day 28) by an ophthalmologist who was blinded to the medication. At each time point, a complete ophthalmic examination was performed and accommodation amplitude (AA), and pupillary diameter (PD) in dim and bright light were recorded. As well, tear secretion was assessed based on tear film break-up time and Schirmer I-test results. Statistical comparisons were made using the chi-square test, Student's t-test and Mann-Whitney U-test, as appropriate.
Results: Twenty-eight patients (56 eyes) received tolterodine and 24 patients (48 eyes) received oxybutynin. The mean ages of the two groups were similar (P = 0.523). After 4 weeks of treatment, AA was significantly lower in the oxybutynin treated group (P = 0.003, 95% CI 0.15, 0.62) whereas there was no significant change in AA in the tolterodine treated group (P = 0.155, 95% CI -0.042, 0.86). At day 28, PD in dim light was significantly larger in the tolterodine treated group (P = 0.031, 95% CI -0.82, -0.06), whereas no significant change in PD in dim light was noted in the oxybutynin treated group (P = 0.330, 95% CI -0.38, 0.18). Neither group showed a significant change in PD in bright light values on day 28 (P > 0.05 for both). In each group, the differences from day 0 to day 28 for intraocular pressure, and Schirmer-I results were insignificant (P > 0.05 for all). Both groups had significantly shorter tear film break-up time after 1 month of therapy (P = 0.014 (95% CI 0.47, 3.81) and P = 0.02 (95% CI 1.14, 4.61) for the tolterodine and oxybutynin treated groups, respectively).
Conclusion: Four weeks of standard-dose oxybutynin treatment in women with overactive bladder decreases AA significantly, whereas the same duration of standard-dose tolterodine does not have this effect. However, tolterodine seemed to affect PD in dim light. One month of treatment with either of these anticholinergic drugs shortens tear film break-up time significantly. Concerning ocular side-effects, tolterodine seems to offer an advantage over oxybutynin because it does not affect AA, however, the shorter tear film break-up time with both agents suggests potential problems for patients who already have dry eye.