Physiological mechanisms of prostaglandin analogues on lowing intraocular pressure / 国际眼科杂志(Guoji Yanke Zazhi)

@#Pathological elevation of intraocular pressure(IOP)is the most prevalent risk factor in the development and progress of glaucoma. Up to date, all treatments for glaucoma are aimed to lower IOP through surgeries and drugs. Prostaglandin analogues are the first-line IOP-lowing drugs for glaucoma due to their ability to reduce IOP. Enough evidences have suggested that they increase aqueous humor outflow through uveoscleral pathway. More recently, people found that bimatoprost was able to increase aqueous humor outflow through trabecular meshwork-Schlemm's canal pathway. Nowadays, a large number of studies are performed to study the mechanism of prostaglandin analogues on lowing intraocular pressure.

The Short-Term Effect of Prostaglandin Analog Monotherapy on Corneal Biomechanical Properties in Normal Tension Glaucoma Patients

PURPOSE: To evaluate the effects of short-term prostaglandin analogues treatment on the corneal biomechanics of patients with normal tension glaucoma. METHODS: This study included 52 eyes of 52 patients who were diagnosed with normal tension glaucoma. All patients were divided into two groups; one group (27 eyes) received tafluprost while the other group (25 eyes) received travoprost. Intraocular pressure, Biomechanical properties were measured by using goldmann applanation tonometer, ocular response analyzer before treatment and at 8-week after treatment. RESULTS: The mean decrease in intraocular pressure, Goldmann-correlated IOP (IOPg), corneal-compensated intraocular pressure by using Goldmann applanation tonometer, and Ocular response analyzer were statistically significant in total patients, tafluprost, and travoprost group after using prostaglandin analogues (p < 0.001, p < 0.001, p < 0.001, respectively). Corneal hysteresis showed no statistical differences after treatment in total, tafluprost and travoprost group but corneal resistance factor (CRF) showed statistically significant decrease after using prostaglandin analogues in total, tafluprost, and travoprost group (p < 0.001, p = 0.025, p < 0.001). Upon multivariate analysis, the higher initial IOPg and the lower initial CRF checked, the variation of CRF (CRF in baseline – CRF at 8 weeks) got higher (β = 0.134, p = 0.017). CONCLUSIONS: It is needed to carefully monitor and evaluate the effects of prostaglandin analogues on intraocular pressure associated with initial intraocular pressure and the changes of CRF after prostaglandin treatment in normal tension glaucoma patients. CRF is sensitive factor to short-term changes of intraocular pressure after prostaglandin analogues treatment, and it is required to consider the properties of CRF when we evaluate between progression of glaucoma and corneal biomechanical properties.

Study on the safety profile of Latanoprost and Timolol in primary open angle glaucoma.

Background: Topical beta blockers, Timolol and the prostaglandin F2α analogue Latanoprost are the most common prescribed medications as first line therapy. Their safety profiles have to be compared to justify the same. The objectives of this study were to compare the safety profile of Latanoprost with that of Timolol in the treatment of primary open angle glaucoma. Methods: In this randomized open label 12-week study, 60 patients were randomized to receive either 0.005% of Latanoprost once daily in the evening or 0.5% of Timolol twice daily. Their safety was concluded by monitoring their adverse effects during follow-up visits at 2, 4, 6, and 12 weeks. Results: Bradycardia was seen only in Timolol group whereas ocular adverse effects such as periocular pigmentation, the growth of eyelashes, and conjunctival hyperemia were seen only in Latanoprost group. Ocular discomfort was present equally in both the groups. Foreign body sensation was seen in both the groups, but it was more frequent in Latanoprost group. The blurring of vision was predominantly seen in Timolol group. Corneal anesthesia was seen in one of the patients on Timolol. Conclusions: The incidence of adverse effects was not significantly different between Latanoprost and Timolol therapy. Both had favorable safety profiles. However, Latanoprost has safer systemic side effects profile when compared to Timolol.

Contralateral intraocular pressure lowering effect of prostaglandin analogues.

Background: Though the use of prostaglandin analogues (PGA) for reduction of intraocular pressure (IOP) has shown a marked increase, studies evaluating the contralateral eff ects of PGA are limited. Aims: To evaluate if PGA treatment in one eye has an eff ect on the IOP of the untreated fellow eye. Design: Retrospective study. Materials and Methods: Thirty patients of open-angle glaucoma with no previous antiglaucoma treatment underwent 24-hour diurnal IOP phasing. They subsequently were started on a uniocular trial with PGA, and had offi ce diurnal IOP measurements 6 weeks later. Twenty-four hour diurnal consisted of 8 IOP readings over 24 hours and offi ce diurnal consisted of 4 IOP readings between 8 AM and 6 PM at 3 hourly intervals. Statistical Analysis: IOPs of the fellow eye during the offi ce diurnal were compared with IOPs at similar time points during the 24-hour diurnal using paired t-tests. Results: Mean (± standard deviation) IOP in the treated eye reduced (P < 0.001) from 17.17 ± 3.2 mm Hg at baseline to 13.7 ± 2.4 mm Hg at 6 weeks, while that in the untreated eye reduced from 16.4 ± 3.1 mm Hg to 14.8 ± 2.7 mm Hg (P = 0.01). The decrease in IOP in the untreated fellow eye was statistically signifi cant at 8 AM (2.7 mm Hg, P = 0.003) and 11 AM (2.3 mm Hg, P = 0.01) but not so at 2 PM (1.2 mm Hg, P = 0.10) and 5 PM (0.9 mm Hg, P = 0.19). The amount of IOP reduction in the untreated eye was signifi cantly associated with the magnitude of IOP reduction in the treated eye (β = 0.69, P = 0.008). Conclusion: Uniocular PGA treatment tends to reduce the IOP of the untreated fellow eye.

Reactivation of Herpetic Keratitis in a Patient after Using Two Different Prostaglandin Analogues

PURPOSE: To report a case of herpetic keratitis after administration of two different prostaglandin analogues. CASE SUMMARY: A 68-year-old female with a history of herpetic keratitis in her right eye after using latanoprost seven years previous presented with redness, mild ocular pain and tearing in the same eye. She had also been prescribed travoprost eye drops for both eyes for uncontrolled glaucoma one month earlier. The cornea in her right eye showed a dendritic epithelial defect with focal epithelial erosions. Travoprost treatment was discontinued, and the herpetic keratitis recovered completely in ten days with acyclovir ointment and oral agent. No further recurrence was observed in the following six months.

The Effects of Prostaglandin Analogues on the Corneal Thickness

PURPOSE: To evaluate the effects of prostaglandin analogues on the corneal thickness of patients with primary open-angle glaucoma (POAG) or normal tension glaucoma (NTG). METHODS: This study included 130 eyes of 65 patients who were diagnosed with POAG or NTG. All patients were divided into two groups; one group received prostaglandin analogues, while the other group received alternative ocular hypotensive eyedrops. Corneal thickness, best corrected visual acuity, and flare in the anterior chamber were measured and compared before treatment and at least 24 months (mean: 27 months) after treatment. RESULTS: The mean decrease in corneal thickness was statistically significant in the group using prostaglandin analogues, but not in the control group. Among the various prostaglandin analogues used, travoprost and latanoprost decreased mean corneal thickness, but bimatoprost had no effect. Best corrected visual acuity, refraction power, and flare in the anterior chamber did not change significantly in either group of patients when ocular hypotensive eyedrops were used. CONCLUSIONS: Prostaglandin analogues lower intraocular pressure and decrease corneal thickness if used over a 24 months.