Abstract:
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. Materials and 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). Conclusion: 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.
