OBJECTIVE: To confirm randomized clinical trial results showing that travoprost reduces IOP with sustained efficacy in the afternoon, 20-24 hours after the last instillation. METHODS: Patients treated with a prostaglandin analogue monotherapy for ocular hypertension or glaucoma were included in this cross-sectional retrospective survey. Demographics, anamnesis, previous treatments were collected from medical chart. IOP and the last instillation time were collected during the visit. ANOVA, logistic regressions and propensity scores were used to compare the 2 treatments. RESULTS: 2,503 patients were included by 494 ophthalmologists. Patients averaged 64 years old (45% male). 2,052 patients were treated with travoprost or latanoprost and the last instillation time was documented for 1,702 of them. 1,241 patients had properly used their medication within the previous day and 461 patients had failed to take it. IOP was 25 mmHg at diagnosis and 22.5 mmHg at the initiation of the current treatment. The two groups were comparable but travoprost-treated patients had a shorter disease and treatment duration. When the instillation was given during the day before, travoprost better controlled IOP at 12.00 and 16.00 hours (16.79 versus 17.51 mmHg; P<0.05) and after 16.00 (16.55 versus 17.67 mmHg; P<0.003). When the interval time between the instillation and IOP recordings was > 24 hours, travoprost-treated patients had a lower IOP (16.76 versus 17.80 mmHg; P<0.002). The percentage of patients reaching the pre-defined target IOP was higher with travoprost than with latanoprost, independent of instillation time (81.9% versus 67.3% (P<0.0001) when intake was the previous day, and 78.5% versus 68.3% (P<0.03) when intake > 24 hours. These differences persisted after adjustment for confounding factors. CONCLUSION: This observational survey confirmed the previous clinical data demonstrating that travoprost uniformly controls IOP through the day with a strong remnant effect, since IOP remains well controlled for more than 24 hours.