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Erschienen in:
01.08.2004 | Clinical Investigation
The influence of Latanoprost 0.005% on aqueous humor flow and outflow facility in glaucoma patients: a double-masked placebo-controlled clinical study
Erschienen in: Graefe's Archive for Clinical and Experimental Ophthalmology | Ausgabe 8/2004
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Background
Fluorophotometry and pneumotonography were performed to investigate the effect of Latanoprost 0.005% and Placebo on aqueous humor flow and total outflow facility in human glaucomatous eyes.
Methods
In a randomised double-blind clinical study patients with POAG and OHT received either latanoprost 0.005% or placebo once in the evening. Fluorophotometry (Fluorotron Master II, Ocumetrics) and Pneumatonography (Model 30 Classic Pneumatonometer, Mentor) was performed in 20 eyes of 10 patients (verum) and 22 eyes of 11 patients (placebo). During a 2 week wash-out period all patients received a systemic antiglaucomatous therapy (Acetazolamide) up to 3 days before baseline measurement. Patients with an IOP higher than 28 mmHg at baseline were excluded. Fluorophotometry, tonography and IOP were measured at baseline after 1 and 2 weeks of treatment. Data was analysed by the Student’s paired t test.
Results
All patients completed the protocol. The IOP significantly decreased (25%) after 1 and 2 weeks of treatment with Latanoprost (p<0.01). Fluorophotometry measurements showed no difference in flow over time in both groups. Although tonographic mean C values in both groups did not show any difference over time, the estimated total outflow facility C (Goldmann) increased significantly (p<0.05) in the verum-treated eyes after 2 weeks. A significant difference of outflow coefficient correlated to normal pressure (P0/C) was found after 2 weeks of treatment with Latanoprost (p<0.05).
Conclusions
In accordance with the literature we found a mean 25% decrease in IOP after 2 weeks of treatment with Latanoprost 0.005%. The analysis of flow values in both groups showed no increase or decrease in aqueous humor dynamics as proved in many previous studies. The known effect of Latanoprost to increase uveoscleral outflow by remodeling extracellular matrix and widening intermuscular spaces in the ciliary body may not be detected by pneumatonography after 2 weeks of treatment. The significant increase in estimated total outflow facility (Goldmann formula) in latanoprost-treated eyes and the decrease of IOP took place at constant flow rates. The increase in conventional outflow facility may indicate trabecular meshwork changes, but it cannot explain the significant decrease in IOP. Furthermore, an additional effect, e.g. uveoscleral outflow, may play the major role as considered in many previous studies.