The influence of Latanoprost 0.005% on aqueous humor flow and outflow facility in glaucoma patients: a double-masked placebo-controlled clinical study.
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 randomized double-blind clinical study patients with POAG and OHT receive either Latanoprost 0.005% or placebo once in the evening. Fluorophotometry (Fluorotron Master II, Ocumetrics) and, Pneumotonography, 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 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 co-efficient 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 the 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 increase uveoscleral outflow by remodeling extracellular matrix and widening intermuscular spaces in the ciliary body may not detected by pneumotonography 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.
Dinslage
Sven
S
Department of Ophthalmology, University of Cologne, Joseph-Stelzmann-Strasse 9, 50924 Cologne, Germany. sven.dinslage@uni-koeln.de
Hueber
Arno
A
Diestelhorst
Michael
M
Krieglstein
Günther
G
D000328:Adult; D001082:Aqueous Humor / Q000187:drug effects*; D004311:Double-Blind Method; D015590:Fluorophotometry; D005902:Glaucoma, Open-Angle / Q000188:drug therapy* / Q000503:physiopathology*; D006801:Humans; D007429:Intraocular Pressure / Q000187:drug effects; D000077338:Latanoprost; D008875:Middle Aged; D009798:Ocular Hypertension / Q000188:drug therapy / Q000503:physiopathology; D011461:Prostaglandins F, Synthetic / Q000008:administration & dosage* / Q000627:therapeutic use; D012996:Solutions; D013997:Time Factors; D016896:Treatment Outcome
D011461:Prostaglandins F, Synthetic; D012996:Solutions; D000077338:Latanoprost