Timolol 0.5% versus Latanoprost 0.005% as A Single Hypotensive Drug in Glaucoma Patients: A 2-year Follow-up

Abstract

Background: Glaucoma is a progressive optic nerve disease that, despite its treatment, is associated with retinal ganglion cell damage. However, timely treatment hinders the progression of visual field damage and preserves visual function. Our study aimed to evaluate the treatment outcomes and adverse effects in glaucomatous patients of using a single anti-glaucomatous agent, 0.5% timolol maleate, or 0.005% latanoprost, for 24 months. Methods and Results: This prospective, single-arm, open-label study included 87 patients (47.13% men and 52.87% women) with open-angle glaucoma treated with a single hypotensive agent. The patients were divided into two groups. Group 1 patients (n=43) were treated with 0.5% timolol, and Group 2 patients (n=44) were treated with 0.005% latanoprost. We assessed the intraocular pressure (IOP) in 7 visits for 24 months, the cup-to-disc ratio (CDR), and the drug's side effects. At baseline (Visit 1), Group 1 showed an IOP(OD) of 26.46±1.99 mmHg and an IOP(OS) of 26.34±2.14 mmHg. Group 2 showed an IOP(OD) of 26.18±1.98 mmHg and an IOP(OS) of 26.18±2.03 mmHg. There were no significant differences between the two treatments at the initial stage. At the second follow-up visit, the mean IOP(OD) and IOP(OS) significantly decreased from baseline in both groups. There was no significant difference between the two treatments at this stage. By the third follow-up visit, IOP continued to decrease effectively in both groups, and no significant difference was observed between the two treatments at this stage. At Visits 4 and 5, in Group 1, the IOP remained without significant dynamics compared to Visit 3. At the same time, in Group 2, the IOP continued to decrease slightly. However, no significant difference was observed between the two treatments at these stages. Latanoprost appears to result in slightly lower IOP levels overall. By the sixth follow-up visit, IOP continued to decrease effectively in both groups. Although latanoprost provided lower IOP values, there was no significant difference between groups. By Visit 7, the difference between the two treatments becomes more noticeable. Group 1 has an IOP(OD) of 16.09±1.26 mmHg and IOP(OS) of 16.00±1.38 mmHg, while Group 2 continued to show lower IOP levels: IOP(OD) of 14.18±1.04 mmHg and IOP(OS) of 14.13±1.09 mmHg. The differences between the groups became significant (P=0.029), indicating that latanoprost was more effective in reducing IOP in the long term. Changes in the CDR used to assess the optic nerve were assessed before and after 24 months of treatment. In Group 1, CDR before treatment was 0.451±0.112 and slightly increased by the end of treatment to 0.484±0.123. In Group 2, CDR before treatment was 0.436±0.138 and slightly increased to 0.452±0.15. With timolol therapy, side effects were found in 11(25.58%) patients, and with latanoprost therapy only in 7(15.9%) patients. Although the differences were not statistically significant, latanoprost had a slightly more favorable safety profile than timolol. Conclusion: The consistently lower mean IOP values for latanoprost treatment suggest it may be more effective in reducing IOP than timolol. However, the lack of statistically significant differences indicates that while one may perform slightly better on average, both treatments are generally effective and may be chosen based on individual patient needs and tolerability.

Keywords

• glaucoma
• intraocular pressure
• timolol
• latanoprost
• cup-to-disc ratio
• adverse effects