Experimental Study on Ocular Surface Protection by Soft Contact Lenses Due to Volcanic Ash Exposure.

Background: Sudden volcanic eruptions can lead to volcanic ash entering the eyes, causing severe discomfort and complicating evacuation efforts. The specific effects of volcanic ash on ocular tissues, especially when wearing soft contact lenses (SCLs), are not well documented, prompting this experimental investigation. Methods: White rabbits with normal eyes were randomly divided into three groups: (1) a bare eye group: bare eye + volcanic ash exposure + eye washing, (2) an SCL group: SCL-wearing eye + volcanic ash exposure + eye washing, and (3) a control group: eye washing only. In groups 1 and 2, volcanic ash was applied to one eye under topical anesthesia, followed by immediate saline rinsing. Slit-lamp microscopy and histopathological analysis were conducted after euthanasia. Results: Slit-lamp and histopathological examinations revealed more significant corneal and conjunctival erosion in the bare eye group compared to the SCL group, which showed limited damage. The control group displayed no ocular damage. Conclusions: Guidelines from the "Volcanic Ash Health Effects: A Guide for the Public" by the National Research Institute for Earth Science and Disaster Resilience recommend removing SCLs during ashfall. Our findings suggest that the damage to the corneal and conjunctival epithelium is less severe in SCL-wearing eyes than in bare eyes, recommending that SCL wearers prioritize evacuation over lens removal during sudden ashfall.