Long-term effects of timolol therapy in ocular hypertension: a double-masked, randomised trial.
BACKGROUND
Increased intraocular pressure (IOP) has been shown to be one of the most important risk factors for developing glaucoma. Yet it has not been clearly demonstrated that IOP-lowering treatment can reduce the incidence of glaucoma damage in patients with ocular hypertension. The aim of the current paper was to report the results of a long-term study addressing this very problem.


METHODS
We conducted a randomised, double-masked study comparing timolol and placebo treatment in 90 patients with ocular hypertension plus some additional risk factor. Patients were followed at 3-month intervals prospectively for 10 years or until glaucomatous field loss could be demonstrated with computerised perimetry. A post-study analysis was performed including all available data, thus extending maximum follow-up to 17 years.


RESULTS
After 5 years of follow-up eight patients in the placebo group and five patients in the timolol group had developed glaucomatous field loss (NS); the corresponding figures after 10 years were 15 patients in the placebo group and seven patients in the timolol group. Survival analysis showed a tendency but no statistically significant difference between treatment groups (P = 0.07). Study attrition was large. Eighteen patients in each group had developed glaucomatous field loss when also post-study data were included. IOP reduction was greater in eyes passing the 10-year visit without field loss (5.7 mmHg), than in those that reached an end-point (2.3 mmHg; P = 0.0002).


CONCLUSIONS
In this long-term study we found a tendency but failed to prove a beneficial effect of topical timolol treatment in patients with elevated IOP, normal visual fields and some additional risk factor. The intent-to-treat analysis showed no difference between treatment groups. The high attrition shows the difficulties associated with very long follow-up.
Heijl
A
A
Department of Ophthalmology, Malmö University Hospital, 20502 Malmö, Sweden. anders.heijl@oftal.mas.lu.se
Bengtsson
B
B
D000319:Adrenergic beta-Antagonists / Q000627:therapeutic use*; D004311:Double-Blind Method; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007429:Intraocular Pressure / Q000187:drug effects; D008297:Male; D008875:Middle Aged; D009798:Ocular Hypertension / Q000188:drug therapy*; D009898:Optic Disk / Q000473:pathology; D011446:Prospective Studies; D012307:Risk Factors; D013999:Timolol / Q000627:therapeutic use*; D014065:Tonometry, Ocular; D016896:Treatment Outcome; D014794:Visual Fields
D000319:Adrenergic beta-Antagonists; D013999:Timolol