Purpose: To study intraocular pressure (IOP) reductions with timolol and latanoprost reached in clinical practice, taking into account data that are routinely collected by the ophthalmologist; to predict IOP reduction from these variables.
Methods: A cohort of patients with primary open-angle glaucoma (suspect) or ocular hypertension was recruited from nine Dutch centres. Mean absolute and relative IOP reduction was calculated in order to compare timolol to latanoprost. IOP reduction was calculated by comparing patients with certain characteristics to those who had none.
Results: One hundred and fifty-six persons started on timolol and 76 started on latanoprost monotherapy. Mean [95% confidence interval (CI)] absolute reduction was 7.2 mmHg (7.9; 6.5) for timolol and 6.9 mmHg (8.0; 5.8) for latanoprost. Mean relative reduction (95% CI) was 27.2% (29.3; 25.1) for timolol and 26.6% (30.2; 22.9) for latanoprost. No significant difference in IOP reduction between timolol and latanoprost was found when adjusting for data that are routinely collected by the ophthalmologist. At the time of starting treatment, none of these items normally used for the management of glaucoma, except IOP at baseline, could predict change in IOP.
Conclusion: In clinical practice, timolol and latanoprost achieve similar IOP reductions that are comparable to those achieved in randomized trials. No clinically relevant information for glaucoma management can be used to predict IOP reduction accurately.