title: Effect of preserved and preservative-free timolol eye drops on tear film stability in healthy Africans.
abstract: BACKGROUND
  Preserved versus nonpreserved formulations for ophthalmic use have been well described in the literature although not specifically in the African population where beta blockers are frequently used as the first-line therapy due to economic and availability issues. This study sought to determine the effect of preserved and preservative-free Timolol eye drops on tear film stability in healthy black Africans.
  
  
  METHODS
  Sixty healthy nondry eye subjects aged 19-25 years were randomly assigned into four groups (n = 15) and differently treated with eye drops of phosphate buffered saline (PBS), preservative-free timolol (PFT), benzalkonium chloride (BAK) only, and BAK-preserved timolol (BPT). Noninvasive tear break-up time (NITBUT) was measured using the keratometer at baseline and 30, 60, and 90 min after drop application.
  
  
  RESULTS
  No significant decline in NITBUT was observed following treatment with PFT and PBS. However, BAK treatment showed a positive time-dependent significant decline in NITBUT (P < 0.001) while a significant decline in the BPT-treated group was only found at 90 min (-3.52 s; P < 0.001). In comparison to the PFT-treated group, treatment with BAK and BPT showed significantly lower NITBUT (P < 0.001).
  
  
  CONCLUSIONS
  BPT is associated with a significant decline in tear film stability in black Africans. This finding has implications in the management of glaucoma in patients with high-risk of dry eyes in this population.
authors.affiliation: Department of Optometry, School of Allied Health Sciences, University of Cape Coast, Cape Coast, Ghana.
authors.forename: Alex
authors.initials: A
authors.lastname: Ilechie
authors.affiliation: Department of Optometry, School of Allied Health Sciences, University of Cape Coast, Cape Coast, Ghana.
authors.forename: Samuel
authors.initials: S
authors.lastname: Abokyi
authors.affiliation: Department of Optometry, School of Allied Health Sciences, University of Cape Coast, Cape Coast, Ghana.
authors.forename: Gifty
authors.initials: G
authors.lastname: Boateng
authors.affiliation: Department of Pharmacology, Faculty of Pharmacy and Pharmaceutical Sciences, College of Health Sciences, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana.
authors.forename: George Asumeng
authors.initials: GA
authors.lastname: Koffuor
keywords: Benzalkonium chloride preserved timolol; glaucoma; keratometer; preservative-free timolol