title: Effect of latanoprost on choroidal blood flow regulation in healthy subjects.
abstract: OBJECTIVE
  The present study tested the hypothesis that human choroidal blood flow (ChBF) regulation in the face of changes in ocular perfusion pressure (OPP) may be modified by a drug-induced decrease in intraocular pressure (IOP).
  
  
  METHODS
  This hypothesis was tested in a double-masked, randomized, placebo-controlled, parallel-group trial in 24 healthy volunteers. OPP was manipulated by 6 minutes of squatting and a subsequent period of artificial increase in IOP induced with a suction cup. These interventions were repeated after 14 days of treatment with either latanoprost or placebo. ChBF was measured continuously with a portable laser Doppler flowmeter.
  
  
  RESULTS
  As expected, latanoprost significantly reduced IOP compared with placebo (P = 0.008). The relative increases in OPP during squatting (P = 0.97) and an artificial IOP increase (P = 0.75), however, were comparable after placebo and latanoprost. The response of ChBF was, in contrast, different between the two treatment groups. During the squatting-induced elevation of OPP, ChBF increased less after latanoprost than after placebo treatment (P = 0.049). During the suction cup-induced increase in IOP, the decrease in ChBF was less pronounced after latanoprost than after placebo (P = 0.026). Latanoprost, however, did not modify baseline ChBF at rest (P = 0.30).
  
  
  CONCLUSIONS
  The data indicate that latanoprost improves ChBF regulation during both an increase and a decrease in OPP. Since latanoprost did not affect baseline ChBF, the authors assume that this effect is related to the decrease in IOP. This finding has important implications for understanding the relation between IOP and vascular factors in glaucoma, because it indicates that a reduction in IOP itself improves ChBF regulation.
authors.affiliation: Department of Clinical Pharmacology, Medical University of Vienna, Vienna, Austria.
authors.forename: Agnes
authors.initials: A
authors.lastname: Boltz
authors.forename: Doreen
authors.initials: D
authors.lastname: Schmidl
authors.forename: Günther
authors.initials: G
authors.lastname: Weigert
authors.forename: Michael
authors.initials: M
authors.lastname: Lasta
authors.forename: Berthold
authors.initials: B
authors.lastname: Pemp
authors.forename: Hemma
authors.initials: H
authors.lastname: Resch
authors.forename: Gerhard
authors.initials: G
authors.lastname: Garhöfer
authors.forename: Gabriele
authors.initials: G
authors.lastname: Fuchsjäger-Mayrl
authors.forename: Leopold
authors.initials: L
authors.lastname: Schmetterer
mesh_terms: D000328:Adult; D000959:Antihypertensive Agents / Q000008:administration & dosage; D002829:Choroid / Q000098:blood supply* / Q000187:drug effects; D004311:Double-Blind Method; D005500:Follow-Up Studies; D006801:Humans; D007429:Intraocular Pressure / Q000187:drug effects*; D017078:Laser-Doppler Flowmetry; D000077338:Latanoprost; D008297:Male; D009883:Ophthalmic Solutions; D011461:Prostaglandins F, Synthetic / Q000008:administration & dosage*; D012016:Reference Values; D012039:Regional Blood Flow / Q000187:drug effects*; D055815:Young Adult
chemical_list: D000959:Antihypertensive Agents; D009883:Ophthalmic Solutions; D011461:Prostaglandins F, Synthetic; D000077338:Latanoprost