Browsing by Author "Mohamed-Ahmed, Abeer H. A."

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    Chlorhexidine gluconate 0.2% as a treatment for recalcitrant fungal keratitis in Uganda: a pilot study
    (BMJ open ophthalmology, 2021) Arunga, Simon; Mbarak, Tumu; Ebong, Abel; Mwesigye, James; Kuguminkiriza, Dan; Mohamed-Ahmed, Abeer H. A.; John Hoffman, Jeremy; Leck, Astrid; Hu, Victor; Burton, Matthew
    Fungal keratitis is a major ophthalmic public health problem, particularly in low-income and middle-income countries. The options for treating fungal keratitis are limited. Our study aimed to describe the outcomes of using chlorhexidine 0.2% eye-drops as additional treatment in the management of patients with recalcitrant fungal keratitis. Methods This study was nested within a large cohort study of people presenting with microbial keratitis in Uganda. We enrolled patients with recalcitrant fungal keratitis not improving with topical natamycin 5% and commenced chlorhexidine 0.2%. Follow-up was scheduled for 3 months and 1 year. The main outcome measures were healing, visual acuity and scar size at final follow-up. Results Thirteen patients were followed in this substudy. The patients were aged 27–73 years (median 43 years). Filamentous fungi were identified by microscopy of corneal scrape samples in all cases. Isolated organisms included Aspergillus spp, Fusarium spp, Candida spp, Bipolaris spp and Acremoninum spp. At the final follow-up, nine patients (75%) had healed; three had vision of better than 6/18. Three patients lost their eyes due to infection. In the remaining nine cases, corneal scarring was variable ranging from 4.6 to 9.4 mm (median 6.6 mm, IQR 5.9–8.0 mm); of these five had dense scars, three had moderate scars and one had a mild scar. None of the patients demonstrated signs of chlorhexidine toxicity during the follow-up. Conclusion Chlorhexidine 0.2% was found to be a useful sequential adjunctive topical antifungal in cases of fungal keratitis not responding to natamycin 5%, which warrants further evaluation.
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    Local Ugandan Production of Stable 0.2% Chlorhexidine Eye Drops
    (Translational Vision Science and Technology, 2023) Picken, Christina A. R.; Brocchini, Steve; Burton, Matthew J.; Blundell-Hunter, George; Kuguminkiriza, Dan; Kaur, Harparkash; Hoffman, Jeremy J.; Arunga, Simon; Mohamed-Ahmed, Abeer H. A.
    The purpose of this study was to develop a protocol to prepare buffered chlorhexidine (CHX) eye drops (0.2% w/v) in the United Kingdom that can be reproduced at a production facility in Uganda. Buffered CHX eye drops can prevent CHX degradation and improve ocular tolerability during the treatment of fungal keratitis. Methods: Buffered CHX eye drops in amber glass containers were prepared using sodium acetate buffer at pH 5.90 to 6.75. Two commercial CHX solutions and CHX in water were used as controls. Eye drops were stored at 40°C (70% humidity, 21 months) in the United Kingdom and at ambient temperature in Uganda (30 months). Highperformance liquid chromatographywas used to determine CHX stability over time, and pH was monitored. Sterility was achieved using an autoclave (121°C, 15 minutes) and water bath (100°C, 30 minutes). Results: The pH of acetate-buffered CHX eye drops did not change over 21 months at 40°C or at ambient temperature (30 months), whereas the pHof the unbuffered aqueous CHX displayed significant fluctuations, with an increase in acidity. The CHX concentration remained the same in both buffered and unbuffered eye-drop solutions. Eye drops sterilization was successful using an autoclave and a water bath. Conclusions: Stable, sterile, buffered CHX eye drops (pH 6.75) were successfully prepared first in the United Kingdom and then reproducibly in Uganda. This eye drops can be prepared in a hospital or pharmacy setting with limited resources, thus providing a cost-effective treatment for fungal keratitis.