Preservative-free travoprost shows equivocal IOP lowering at 1 year after changing therapy
Glaucoma patients who switched from latanoprost, which is preserved with benzalkonium chloride, to BAK-free travoprost had fewer ocular surface complications 1 year later, but experienced no adverse effect on intraocular pressure, according to a recent study.1
In previous studies, OSD index scores improved when clinicians switched patients from preserved to non-preserved drops, but the longest follow-up period was 3 months. With this in mind, Dr Makoto Aihara, PhD, of the University of Tokyo, and colleagues wanted to determine the efficacy and tolerability of BAK-free travoprost (Travatan Z, Alcon) 1 year after changing therapy.
At follow-up visits, the investigators assessed these three outcomes: conjunctival hyperaemia; superficial punctate keratitis (SPK); and IOP.
This is the most common complication related to use of prostaglandin analogues. The researchers used a 4-grade photographic scale of slight, mild, moderate and severe to measure conjunctival hyperaemia.
Conjunctival hyperaemia at baseline was grade 0 in 55 eyes, grade 1 in 11 eyes, and grade 2 in one eye. Although no significant change occurred immediately, hyperaemia at 3 months was grade 0 in 64 eyes, grade 1 in two eyes and grade 2 in one eye. By 12 months, hyperaemia was grade 0 in 64 eyes, and grade 1 in three eyes.
Incidence of SPK
The researchers detected SPK by fluorescein staining observed with a blue-free filter and by using the AreaDensity (AD) classification (scores ranging from 0 to 6). Thirty-six of the 67 eyes (54%) showed evidence of SPK at baseline. The A1D1 score was slight in 25 eyes and mild (A1D2 or A2D1) to severe (A3D2) in the remaining 11 eyes. The study reported fewer cases of SPK at 1 and 3 months, being present in nine of 67 eyes (13%). The researchers classified the SPK as slight in seven eyes and mild in two eyes. One year after the medication switch, SPK was present in 19 eyes (28%). The SPK was classified as slight (A1D1) in 17 eyes and mild (A1D2) in two eyes.
"The fact that the SPK greater than A1D1 improved within 1 month of treatment with BAK-free travoprost, and that the improved corneal condition was sustained for 12 months is noteworthy," the study stated. "However, there were patients with slight SPK (A1D1) throughout the observation period and their number increased at 12 months, compared with 1 or 3 months."
Measurable IOP decline
Mean IOP, measured with Goldmann applanation tonometry, significantly decreased after the transition to BAKfree travoprost and over the course of the trial. It went from 14.9 mmHg at baseline to 14.3 mmHg at 1 month, 13.9 mmHg at 3 months and back to 14.3 mmHg at 12 months. Although travoprost reduced IOP more than latanoprost, the researchers urged caution in evaluating these results because the additional reduction was less than 1 mmHg.