|Year : 2018 | Volume
| Issue : 2 | Page : 118-120
Effect of benzalkonium chloride–preserved timolol maleate on dry eye disease in a black African population, southwestern Nigeria
Oluyemi Fasina1, Segun I Olaniyan2
1 Oculoplastics and Ocular Oncology Unit, Department of Ophthalmology, University of Ibadan/University College Hospital, Ibadan, Oyo State, Nigeria
2 Sheikh Zayed Regional Eye Care Centre, Kanifing, Gambia
|Date of Web Publication||13-Feb-2019|
Dr. Oluyemi Fasina
Oculoplastics and Ocular Oncology Unit, Department of Ophthalmology, University of Ibadan/University College Hospital, Ibadan, Oyo State
Source of Support: None, Conflict of Interest: None
Objective: Benzalkonium chloride, a commonly used preservative in many ophthalmic preparations, has been postulated as a cause of ocular surface toxicity, resulting in dry eye disease in patients on long-term treatment with topical medications. This study aims to determine the effect of benzalkonium chloride–preserved timolol maleate on dry eye disease in an African population. Materials and Methods: Information was retrieved from the data generated at a cross-sectional study on the prevalence of dry eye disease conducted in a randomly selected local government area, southwestern Nigeria, and analysis was conducted on participants with glaucoma and using benzalkonium chloride–preserved timolol maleate (cases), and age- and sex-matched controls. Results: One hundred and seventy-four participants were included in this study with a mean age of 65.05 ± 11.65 years. There was no significant association (P > 0.05) between the use of benzalkonium chloride–preserved timolol maleate and tear-film break-up time, Schirmer 1 test, fluorescein staining score, and overall diagnosis of dry eye disease in the patients. Conclusion: Benzalkonium chloride–preserved timolol maleate did not contribute significantly to dry eye disease in the studied population.
Keywords: Benzalkonium chloride, case–control study, dry eye disease, Nigeria, timolol maleate
|How to cite this article:|
Fasina O, Olaniyan SI. Effect of benzalkonium chloride–preserved timolol maleate on dry eye disease in a black African population, southwestern Nigeria. Niger J Ophthalmol 2018;26:118-20
| Introduction|| |
Dry eye disease has been defined by the International Workshop on Dry Eye as a multifactorial disease affecting the precorneal tear film and ocular surface with symptoms of tear-film instability and ocular discomfort. Benzalkoniun chloride (BAC) is a quaternary cationic surfactant, and the most commonly used preservative for ophthalmic topical medications. It has been implicated in contributing to the ocular toxicity and inflammation associated with chronic use of the topical ophthalmic preparations.,, BAC has a long half-life of about 20 h in the corneal epithelium and conjunctival tissues after instillation; thus, prolonged exposure to the ocular surface tissue leads to inflammatory cell infiltration, increased corneal epithelial cell permeability, and impaired epithelial barrier function.,, However, it is not conclusively agreed upon that BAC is solely responsible for this dysfunction, as some authors opined that the additive combination of BAC with the active drug may be contributory. Glaucoma is a major blinding disease among Nigerians and BAC-preserved timolol maleate is one of the commonly used topical medications in treating the disease due to its affordability. In addition, dry eye disease has been reported to be fairly common in the general Nigerian population with a prevalence of 19.2%. Hence, we set out to determine if there are an association between the BAC-preserved timolol maleate and dry eye disease among a Nigerian population.
| Materials and Methods|| |
A community-based survey on dry eye disease among adults of 40 years and above was conducted at Iseyin Local Government Area of Oyo State, southwestern Nigeria, by a random sampling technique, and details of the methods of this survey had been published. Included for analysis in this study were individuals in the survey with chronic glaucoma who were on treatment with benzalkonium-preserved timolol maleate 0.5% twice daily for a minimum of 3 months (cases), and age- and sex-matched controls. Information on their sociodemographics; history of ocular and systemic diseases and medications; detailed ocular examination including results of Schirmer 1 test, tear-film break-up time, and corneal fluorescein staining score; the administered six-item questionnaire (a part of the Salisbury Eye Evaluation Questionnaire relating to symptoms of dry eye); and the diagnosis of dry eye disease were retrieved. The diagnosis of dry eye disease was made in the survey by the simultaneous presence of at least one symptom experienced “often or all of the time” and at least one sign in either eye of the participants.
Data were analyzed using the Statistical Package for Social Sciences software (SPSS for Windows, version 21.0; SPSS, Inc, Chicago, Illinois, USA). Quantitative data were analyzed using descriptive statistics (means with standard deviation), and Chi-square test was used to measure the association between categorical variables with level of significance set at 5%.
| Results|| |
One hundred and seventy-four patients made up of 87 cases and 87 controls were included in this study with a mean age of 65.05 ± 11.65 years. There was no significant difference in the mean age between the cases 65.61 ± 11.87 years and controls 64.48 ± 11.47 years (P = 1.00). The age and sex distribution of the patients are shown in [Table 1].
There was no significant association (P > 0.05) between the use of BAC-preserved timolol maleate and tear-film break-up time (P = 0.879), Schirmer 1 test (P = 0.254), fluorescein staining score (P = 1.000), and the diagnosis of dry eye disease (DED) (P = 0.168) [Table 2].
|Table 2 Bivariate analysis of effect of BAC-containing timolol maleate on dry eye disease|
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| Discussion|| |
Timolol maleate is commonly used in the treatment of glaucoma, the most common cause of irreversible blindness in Nigeria. Presumably, compliance with long-term use of the topical medications is affected by the discomfort experienced on instillation of the drug by the patients. This could be attributed in part to the ocular surface toxicity induced by the commonly used BAC preservative in the drug, or the additive effect of the preservative and active drug.
In this study, no significant association was observed between dry eye disease and use of BAC-preserved timolol maleate among the studied population. This is at variance with the reports of Baudouin et al. and Chhabra et al. Baudouin et al. reported significant deleterious cytotoxicity of BAC with cultured conjunctival cells, although they conducted an in vitro study of the BAC-containing and preservative-free prostaglandin analogs and the limitation of a direct extrapolation of the findings to humans in vivo was expressed by the authors. Our findings also differ from the report of Pisella et al., and this could be attributed in part to the longer duration of use of benzalkonium-containing antiglaucoma medications by patients in their study. However, a synergistic effect between the active drug and BAC preservative was postulated by Pisella et al. who demonstrated that BAC 0.02% preparation induced a significantly greater conjunctival cell toxicity followed by latanoprost-containing 0.02% BAC, and timolol containing 0.02% BAC, whereas the least toxicity was observed with preservative-free timolol. They opined that different antiglaucoma medications may have varying protective effects on the toxicity of BAC on the conjunctival cells. In addition, a dose-dependent toxic effect of BAC has been documented ranging from slow cell growth reduction at lower concentrations (0.0001%) to outright epithelial cell death at higher concentrations (0.05%).,, This dose-dependent cytotoxic effect of BAC could not be elicited in this study due to the secondary data that was analyzed, and this is a limitation to this study.
In conclusion, the use of BAC-preserved timolol maleate is not associated with a higher prevalence of dry eye disease in our region, suggesting that the documented toxic effect of BAC on the ocular surface cells may not result into dry eye disease in our patients. However, further studies, possibly crossover designed, using BAC-containing and preservative-free topical mediations are needed and recommended among our patients to evaluate the direct toxic effects of BAC on ocular surface tissue and resultant dry eye disease.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Table 1], [Table 2]