Ocular hypotensive effects of prostaglandin analogs in Japanese patients with normal-tension glaucoma: a literature review

PURPOSE: This paper aimed to evaluate the intraocular pressure (IOP)-lowering effects of prostaglandin analogs (PGAs) in Japanese patients with normal-tension glaucoma (NTG) by reviewing the current literature. METHODS: In February 2018, database searches were performed in PubMed, Embase, ProQuest, and the Japanese databases JAPICDOC and JMEDPlus. Studies were sorted into two categories: Category 1 consisted of studies of patients with NTG who reported reduced IOP values and Category 2 consisted of studies of patients with NTG who had IOP values at predosing and a final evaluation point. Search terms included ([unoprostone or latanoprost or travoprost or bimatoprost or tafluprost] and [glaucoma] and [Japan or Japanese]). The weighted ocular hypotensive efficacy was calculated. A scatter plot analysis was performed and a regression equation was calculated for each medication. The fitting of each regression equation was evaluated by the least squares method. RESULTS: Eleven articles were eligible for Category 1 and 25 articles for Category 2. In the rank order of IOP-lowering efficacy of PGAs, bimatoprost was the strongest and latanoprost the weakest. Travoprost and tafluprost had almost the same level of ocular hypotensive effect, and both were stronger than latanoprost. The scatter plot analysis showed that all PGAs reduced IOP by 15%–20%. At higher IOP (17–18 mmHg), the ocular hypotensive effect was almost the same with latanoprost, travoprost, and tafluprost. In contrast, at lower IOP (12–15 mmHg), the IOP reduction with latanoprost was weaker than with travoprost or tafluprost. CONCLUSION: This literature review of the ocular hypotensive effects of PGAs in Japanese patients with NTG highlighted that PGAs had different ocular hypotensive effects. Ophthalmologists should understand the IOP-lowering profiles of various PGAs and apply them to patients with NTG on a case-by-case basis. TRIAL REGISTRATION: UMIN Clinical Trials Registry UMIN000032344.