Evaluation of Tear and Anterior Chamber Fluid Samples for Benzalkonium Chloride During Long-Term Glaucoma Treatment

Abstract

Purpose : Benzalkonium chloride (BAK) is a widely used preservative in ophthalmic medications, as well as hygiene and cosmetic products. Experimental studies showed BAK’s presence in ocular tissues, however the extent to which it accumulates during chronic topical glaucoma therapy is uncertain. A prospective case-control study was performed to test for the presence of BAK in tear and in anterior chamber fluid (ACF) samples in patients undergoing long-term topical therapy for open angle glaucoma (OAG).

Methods : Study group consisted of 22 cataract patients with OAG who received topical treatment for >2 years and 34 controls free from eye disease (other than cataract) with demographics in Figure 1.
Figure 1. Demographics of study groups.
A full ophthalmic examination and Schirmer’s test to collect tear fluid samples were performed in all study patients scheduled for routine cataract surgery, during which 0.1 ml ACF samples of were collected. Analytical sample preparation was carried out by ultrasonic-assisted extraction. Schirmer’s test paper strips were placed into the vials containing 1 ml of a mixture of methanol and acetonitrile (50/50) and sonicated for 30 min at 40°C. Extracts were evaporated using nitrogen gas and dry residue dissolved in 100 µl of acetonitrile. Test samples were assayed by LC-MS/MS in positive ionization mode using Acquity UPLC H-Class module and TQD MS detector (Waters, Milford USA). Methanol containing 0.1% of formic acid was used as mobile phase. Empty Schirmer’s strips without tear samples were found to have BAK and were used as negative control. A positive result in tear samples was assumed when a higher BAK peak area was detected compared to empty strips. Statistical analysis was performed with SPSS v23.0 program package.

Results : Mean (SD) of glaucoma medication drops/day containing BAK in OAG group was 2.9 (0.7) while the control group did not receive any treatment.
Figure 2. BAK presence in tear fluid samples did not differ significantly between groups (Χ² =3,221, df = 1, p = 0,092).
None of the ACF specimens were found to have detectible BAK in either OAG or control groups.

Conclusions : Our data suggests that there is not a significant presence of BAK in tears of OAG patients undergoing long term topical therapy. In addition, no detectible level of BAK was found ACF samples in the for either OAG or control groups.

This abstract was presented at the 2022 ARVO Annual Meeting, held in Denver, CO, May 1-4, 2022, and virtually.