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Yureeda Qazi, Andrea Cruzat, Bernardo M Cavalcanti, Clara Colon, Debora Witkin, Teresa C Chen, Pedram Hamrah; The In Vivo Effect of Preservative Benzalkonium Chloride on Corneal Immune Cells and Clinical Signs in Glaucoma Therapy. Invest. Ophthalmol. Vis. Sci. 2016;57(12):3028.
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© ARVO (1962-2015); The Authors (2016-present)
To determine the effect on in vivo corneal immune response and clinical signs by the preservative benzalkonium chloride (BAK) in ocular hypotensive drugs for glaucoma before and after treatment, comparing BAK-preserved and BAK-free prostaglandin analogues.
A randomized, longitudinal, controlled, double-masked clinical trial was conducted with 14 treatment-naive subjects (66.8±2.4 years) newly diagnosed with glaucoma, who received either BAK-preserved (latanoprost, LAT, n=7), or BAK-free ionic buffered system-preserved (travoprost, TRAV, n=7) prostaglandin analogue for 6 months. Central corneal DC densities of both eyes were quantified on IVCM at baseline, 1 month and 6 months post-treatment by a masked observer. Clinical improvement was assessed by intraocular pressure (IOP), corneal fluorescein staining (CFS) and tear break-up time (TBUT). Parametric and non-parametric tests were applied.
After 1 month of treatment, BAK-preserved LAT-treated eyes showed a 10% increase in DC density (baseline=126.0±33.2 cells/mm2, 1 month= 138.8±42.6 cells/mm2) in contrast to the BAK-free TRAV-treated eyes, which showed a 29% decrease in DC density (baseline= 90.63±22.6 cells/mm2, 1 month= 63.4±18.7 cells/mm2). This initial increase of corneal immune response in the BAK-preserved LAT-treated eyes resolved by 6 months (DC= 118.1±29.1 cells/mm2), while the BAK-free TRAV-treated eyes continued to maintain lower DC densities (DC=57.3±24.8 cells/mm2). Consistent with the initial increase and subsequent decrease of DCs in the LAT-treated eyes, TBUT initially decreased by 29% (LAT 1 month= 5.6±1.2s, TRAV 1 month= 9.25±1.6s, P=0.04) but stabilized by 6 months, comparable to that of TRAV-treated eyes (LAT 6 months= 6.3±0.7s, TRAV= 6.7±1.8s, P=0.6). IOP reduced significantly at 1 month with both LAT (P=0.03) and TRAV (P=0.007), to a comparable extent (P=0.40). CFS did not show any changes between both groups.
IVCM demonstrated an increased ocular surface immune response to BAK in glaucoma therapy, which was observed as an early increase in DC density that began to subside by 6 months of therapy, not detected with clinical tests (CFS). This increase in DCs was accompanied by a decrease in TBUT. The ionic buffered system preservative did not activate the corneal immune response, and may offer a non-immunogenic alternative to eye drop preservatives for glaucoma therapy.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.
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