Prostaglandin Analogs and Blood-Aqueous Barrier Integrity: A Flare Cell Meter Study

Abstract

Purpose: To study, with an objective method, inflammation of the anterior segment of the glaucomatous eye after treatment with latanoprost, travoprost and bimatoprost. Materials and Methods: 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. Results: 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). Conclusions: 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.

The effects of prostaglandin analogues on the blood aqueous barrier and corneal thickness of phakic patients with primary open-angle glaucoma and ocular hypertension

“…[8][9][10][11][12][13][14][15][16][17] However, there is controversy regarding the effects of PG analogues on the BAB of phakic patients with no previous history of surgery or uveitis. [18][19][20][21][22][23][24] Furthermore, it has been reported that topical application of PG analogues may also reduce central corneal thickness (CCT), 25 which could influence IOP measurements by applanation tonometry. [26][27][28] While it is important to evaluate the ocular hypotensive efficacy of PG analogues, it is also necessary to determine their effects on the ocular surface and intraocular inflammatory reaction of phakic patients.…”

“…However, the authors do not mention if patients with a previous history of intraocular surgery/ laser were allowed to enter the study. The inclusion of patients with a previous history of BAB breakdown might justify the increased mean flare values observed by Cellini et al 20 following the use of PG analogues. In our series, no statistically significant increase in mean flare values from baseline was found when patients used bimatoprost, latanoprost, or travoprost for 4 weeks.…”

Clinical utility and differential effects of prostaglandin analogs in the management of raised intraocular pressure and ocular hypertension

“…68 Several meta-analyses [88][89][90][91] have directly compared the clinical efficacy of the three main PGAs, latanoprost, travoprost, and bimatoprost. Two independent meta-analyses, one 88 of 8 63,64,68,78,[85][86][87]92 and the other 89 of 13 trials (including double-blind parallel 57,63,93 or cross-over studies 41,42 and single blind parallel 64,78,85,86,[94][95][96] or cross-over studies) 97 found bimatoprost was superior to latanoprost in lowering morning IOP at all time points, supported by a later posthoc meta-analysis of 2 independent trials with 6 months follow-up. Weighted mean difference (WMD) for %IOP reduction (%IOPR) was 2.59% (P = 0.004) at 1 month to 5.60% (P , 0.001) at 6 months for one meta-analysis 89 and weighted mean (WM) IOP change from baseline ranged from a minimum of 0.50 mmHg (P = 0.05) at 0800 hours to a maximum of 1.17 mmHg (P , 0.001) at 1200 hours in the other meta-analysis 88 favoring bimatoprost over latanoprost.…”

“…Studies comparing the PGA to other non-PGA glaucoma treatments, nonrandomized, dose-finding or cross-over trials, and short-term evaluations (less than 3 months) were excluded, although a trial evaluating timolol plus travoprost versus timolol alone, 100 was included indicating that the PGA effect has the same relative effect as if it were compared with no treatment. Another industry-sponsored meta-analysis by Denis et al 91 of 9 randomized trials 63,68,78,85,86,92,93,101,104 (n = 1318) found adjusted IOP was similar for bimatoprost and travoprost, but more favorable than latanoprost treated subjects. Authors commented that 4 trials evaluating latanoprost vs timolol, were not included which may have lead to a lower IOP decrease for latanoprost compared with the meta-analysis by van der Valk.…”

“…Bimatoprost was superior in IOP lowering to travoprost only during the daytime (0800 and 1200 hours time-points), but latanoprost and travoprost were comparable at all time points (P # 0.82). 88 An industry-sponsored meta-analysis 90 of travoprost vs latanoprost (15 trials, n = 1098), 57,68,85,93,95,96,[98][99][100] travoprost vs bimatoprost (8 trials, n = 714), 57,85,87,93,95,96,101,102 and latanoprost vs bimatoprost (8 trials, n = 943) 57,64,85,86,93,95,96,103 found similar efficacy among the three PGAs. Studies comparing the PGA to other non-PGA glaucoma treatments, nonrandomized, dose-finding or cross-over trials, and short-term evaluations (less than 3 months) were excluded, although a trial evaluating timolol plus travoprost versus timolol alone, 100 was included indicating that the PGA effect has the same relative effect as if it were compared with no treatment.…”