Purpose To compare the effect of different concentrations of benzalkonium chloride (BAK) in topical medications used postcataract surgery on the ocular surface. Patients and methods A prospective randomized clinical trial including 60 eyes of 60 cataract patients who had a healthy ocular surface preoperatively. After phacoemulsification, patients were randomized into three groups. Twenty eyes received a single-dose unit of dexamethasone 1 mg and netilimicin 3 mg without BAK (Dexathalm SDU), 20 eyes received regular tobramycin 3 mg and dexamethasone 1 mg, preservative: 0.1 mg of BAK per ml (Tobradex), and 20 eyes received dexamethasone 1 mg and netilimicin 3 mg and 0.05 mg/ml BAK (Dexathalm multidose). All medications were given five times per day. Noninvasive tear break-up time, tear meniscus height, meibomian gland loss, and ocular surface disease index were assessed preoperatively and 4 weeks after surgery. Results The single-dose dexamethasone 1 mg and netilimicin 3 mg without BAK (Dexathalm SDU) group showed better ocular surface parameters compared to the dexamethasone 1 mg and netilimicin 3 mg and 0.05 mg/ml BAK (Dexathalm multidose) and the tobramycin 3 mg and dexamethasone 1 mg, preservative: 0.1 mg/ml BAK (Tobradex) groups. It had the longest noninvasive tear break-up time (15.39±4.04 vs. 14.80±4.23 vs. 12.68±5.60, P =0.166), the highest tear meniscus height (0.24±0.05 vs. 0.22±0.04 vs. 0.18±0.04, P =0.001), and showed no loss in the meibomian glands. Conclusion The incidence of dry eye postcataract surgery is influenced by the concentration of BAK preservatives in the medications.
Amin et al. (Thu,) studied this question.