Abstract
Purpose :
Demodex is a commonly overlooked contributor in ocular surface inflammatory diseases. Consensus was reached on the symptoms and diagnosis but not on the most effective treatment of ocular demodicosis. A novel clinical observation suggests the efficacy of 5-fluorouracil (5-FU) in treating demodex associated blepharitis and chalazia. In this in-vitro study, we evaluated the demodicidal effect of 5-FU (500mg/10 ml, 5%) in comparison to a control (0.9% saline solution).
Methods :
Live demodex mites from individuals with blephritis were obtained by eyelash sampling based on the observation of pathognomonic cylindrical dandruff, a hallmark sign of demodex blepharitis. The forceps-epilated lashes were transferred to glass slides and immersed in 2-3 drops of test solution after applying a cover slip. Counts were recorded as the number of live adults demodex observed under the microscope (20-40X magnification) every 10-15 minutes. The kill time was defined as the elapsed time between the immersion of test solution and all cessation of movement of the body, legs, mouth or pedipalps of demodex for a minimum of 60 seconds.
Results :
20 viable adult demodex were obtained from 4 human subjects. 5-FU had a significant shorter kill time of 147 ± 24 minutes compared to 173.5 ± 34 minutes of saline solution (p=0.03). The survival time for demodex exposed to 5-FU (n=10) and saline solution (n=10) ranged from 102 to 186 mins and 114 to 228 mins, respectively.
Conclusions :
5-FU was effective in killing adult demodex in vitro compared to control. As it is FDA approved for other ophthalmic uses (ocular surface squamous neoplasia, glaucoma or pterygium surgery) we beleive it has potential to be a useful adjunct topical therapy in the managment of chronic blepharitis after optimizing therapeutic concentration
This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.