Research Article
Volume 12 Issue 3 - 2021
The Threshold of Ultraviolet Light Energy to Eliminate Acanthamoeba
Ahmara G Ross1,2 and Regis P Kowalski2*
1Scheie Eye Institute, University of Pennsylvania, Philadelphia, Pennsylvania, USA
2The Charles T Campbell Ophthalmic Microbiology Laboratory, Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
*Corresponding Author: Regis P Kowalski, The Charles T Campbell Ophthalmic Microbiology Laboratory, Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA.
Received: January 04, 2020; Published: February 27, 2021


Purpose: Acanthamoeba keratitis is a contact lens-related infection that may result in significant visual impairment. Treatment of Acanthamoeba keratitis can be difficult due to a lack of good medical therapy. Acanthamoeba can survive in contact lens storage cases and on the surface of contact lenses for extended periods of time. The aim of this study was to determine the threshold of Ultraviolet energy (UVE) to eliminate Acanthamoeba from contact lens and cases. We hypothesize that UVE with and without riboflavin will eradicate Acanthamoeba while maintaining the clarity of the lens.

Methods: The Stratagene UV Stratalinker 2400 Crosslinker™ was used to administer UVE in pulses to eliminate Acanthamoeba castellanii. Multiple modes of energy delivery were administered in a dose-dependent manner in microjoules/cm2 x 100. Three groups were tested: 1) Acanthamoeba castellanii (106 cysts in saline) exposed to UVE alone; 2) Acanthamoeba castellanii (106 cysts in saline) plus soft contact lens exposed to UVE alone; 3) Acanthamoeba castellanii (106 cysts) plus soft contact lens exposed to UVE in a saline solution of 0.01% Riboflavin. Acanthamoeba castellanii viability was monitored for growth using non-nutrient agar with Enterobacter aerogenes overlay. The soft contact lenses were for evaluated for clarity by spectrophotometry.

Results: A total UVE of 89,991 microjoules x 100/cm2 for a total of 180 min (3 hours) were required to eliminate Acanthamoeba castellanii solutions. A total of 99990 microjoules x 100/cm2 for a total of 200 minutes was required to eliminate Acanthamoeba castellanii from solutions with contact lenses with and without riboflavin. One large dose in this amount of UVE did not effect the clarity of soft contact lenses in the time-frame of this study.

Conclusion: A very large dose of UVE had the potential to eliminate Acanthamoeba from solutions. Even more energy is required to kill Acanthamoeba with contact lens in solution. A one time exposure of contact lens to 89,991 - 99990 microjoules x 100/cm2 UVE may produce minimal damage to soft contact lens.


Keywords: Acanthamoeba; Total Kill Assay; Riboflavin; UV Light Exposure


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Citation: Ahmara G Ross and Regis P Kowalski. “The Threshold of Ultraviolet Light Energy to Eliminate Acanthamoeba”. EC Ophthalmology 12.3 (2021): 07-11.

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