Prostaglandin analogs and blood-aqueous barrier integrity: a flare cell meter study

To study, with an objective method, inflammation of the anterior segment of the glaucomatous eye after treatment with latanoprost, travoprost and bimatoprost.

Sixty patients with chronic open-angle glaucoma aged between 38 and 76 years (mean 64.0 +/- 12.2) were randomly assigned to latanoprost 0.005, travoprost 0.004 and bimatoprost 0.03%. The study period lasted 6 months. Intraocular pressure (IOP) was measured every 2 weeks. We studied the intraocular inflammation before and after 3 and 6 months of therapy with an instrument composed of a He-Ne laser beam system, a photomultiplier mounted on a slitlamp microscope and a computer. This flare meter allows objective determination of the flare and the number of cells in the aqueous of the anterior chamber.

At the baseline, IOP was 26.4 +/- 3.6 mm Hg. After 3 months of treatment, mean IOP in the latanoprost group was 17.9 +/- 0.3 mm Hg (p < 0.001) with a mean cellularity of 12.638 +/- 3.284 photons/ms (p < 0.001). The travoprost group had an IOP of 17.2 +/- 0.3 mm Hg (p < 0.001) with a cellularity of 9.719 +/- 1.927 photons/ms (0.001). Finally, IOP in the bimatoprost group was 17.6 +/- 0.5 mm Hg (p < 0.001) with a cellularity of 6.138 +/- 1.475 photons/ms (p < 0.032). After 6 months of treatment, IOP in the latanoprost group was 18.1 +/- 0.3 (p < 0.001), in the travoprost group 17.3 +/- 0.3 (p < 0.001) and in the bimatoprost group 17.7 +/- 0.5 mm Hg (p < 0.001), whereas cellularity was 11.838 +/- 3.218 (p < 0.001), 8.950 +/- 3.692 (p < 0.001) and 7.617 +/- 2.603 photons/ms (p < 0.001), respectively. After 3 months, the travoprost (p < 0.013) and the bimatoprost groups (p < 0.001) had less flare compared with the latanoprost group and this remained so even at 6 months. When we compared the travoprost group with the bimatoprost group, we found significantly less flare at 3 months in the bimatoprost group (p < 0.001) but not at 6 months (p < 0.246).

The flare meter analysis shows that the eyes treated with bimatoprost and travoprost have a less significantly broken blood-aqueous barrier and their anterior chamber is also significantly less inflamed.