Clinical And Tomographic Evaluation Of Ocular Surface In Glaucomatous Patients Treated With Benzalkonium Chloride Medications.

Glaucoma is one of the main causes of blindness in the world. Topical anti glaucomatous drops are still the most important treatment. Previous studies have shown the adverse effects of these drugs on the corneal architecture, especially those containing Benzalkonium chloride (BAK). The BAK is a conservative agent that is used in many anti glaucomatous drugs and is responsible of dryness and ocular surface disease. 

The purpose of our study was to evaluate the tear break up time (BUT) and the central corneal epithelium thickness (CCET) using anterior segment optical coherence tomography in patients with anti-glaucomatous containing benzalkonium chloride.

Ophtalmology departement, Military hospital of tunis, tunisia

The study included 40 patients treated for primary open angle glaucoma with monotherapy (prostaglandin) divided into two groups: 16 patients using bak free prostaglandin (Group 1) and 24 patients using Bak+ prostaglandin. Patients with corneal dystrophy,or presenting with a  history of severe corneal infection or corneal decompensation after cataract surgery, or suffering from systemic disease that may affect the ocular surface, were excluded. We compared the BUT and CCET in the two groups at month 6 and 12 follow-up. CCET was defined on Anterior segment optical coherence tomography (AS-OCT) as the distance between the tear film and the first hypereflective layer (bowman layer). Statistical analysis was made with SPSS statistics V23.  

The mean age of the population was 56 and 58 year-old in group 1 and 2 respectively. The average of Intra ocular pressure was 18 mmHg and 16 mmHg respectively in the two groups during the period of follow up. At 12 month follow-up, BUT was significantly reduced in group one with 6,8 ± 2.3 s in comparison with  8.3 ± 2.4 s in group 2 . The CCET was 46.2 ± 4.2 µm in BAK+ group and 50.5 ± 5.9 µm in Bak free group at 12 month follow up(p < 0.001).

Clinical modifications of the tear film seem to be correlated with CCET changes due to BAK + anti glaucomatous medications.