Technical Report: Reducing Lens Fogging Associated with Patient Mask Wearing with Heated Diagnostic Fundoscopy Lenses

Severe acute respiratory syndrome coronavirus 2 has indirectly created challenges to the ophthalmic retinal examinations because of lens fogging related to patients wearing masks. To date, there are no objective data on the degree of diagnostic ophthalmic lens fogging associated with mask wearing or on the effectiveness of proposed solutions to ophthalmologic lens fogging.

The purposes of this study were to investigate the degree of ophthalmologic lens fogging in patients wearing masks and to assess the efficacy lens warming in reducing lens fogging and facilitating ophthalmologic retinal examinations.

This study quantified the degree of lens fogging in mask-wearing subjects using ImageJ to measure lens surface area fogged in slit-lamp photographs of 90 D lenses before and after the use of a lens warmer. We investigated the clinical relevance of diagnostic lens fogging via a survey study of eye care providers. Subjects rated on a Likert scale their experience with diagnostic lens fogging during retinal examination in mask-wearing patients with and without the use of a lens warming device.

For mask-wearing subjects, the percentage of fogged lens area in a 90 D lens averaged 32.5% using an unheated lens and 1.1% using a heated lens. Survey responders noted significantly less fogging of the 78 and 90 D lenses on retinal examination when using the lens warmer (P < .001) and found that using the lens warmer facilitated their retinal examination (P < .001).

This study shows that there is significant fogging of ophthalmic slit-lamp lenses associated with patients wearing masks and that using a lens warmer significantly reduces fogging and facilitates retinal examinations. Eye care providers would benefit from the use of a lens warmer to reduce diagnostic lens fogging during retinal examination.