Purpose To determine whether the incidence of chalazion increased significantly in the San Francisco Bay Area and Los Angeles County following the widespread adoption of face mask wear in response to the COVID-19 pandemic. Methods This is a retrospective multicenter study of two ophthalmology institutions: a private Oculoplastics practice in San Francisco and the Oculoplastics division of the Stein Eye Institute at the University of California, Los Angeles. All patients seen during the studied time periods with a diagnosis of chalazion or hordeolum were identified through review of electronic medical records and included in the study. Incidence was determined for each month between January and August 2020, and compared to data from prior years via ANOVA to evaluate for changes after the onset of the pandemic. Results In San Francisco, the incidence of chalazion rose significantly in June through August of 2020 when compared to the same interval in 2016, 2017, 2018, and 2019. In Los Angeles, the rise in chalazion incidence in 2020 was also statistically significant when compared to data from the years 2018 and 2019. Conclusion /Importance: Widespread mask wear does appear to correspond to an increased incidence of chalazion. This risk may be minimized, while still maintaining the protective benefits of mask wear, by taking the proactive measures discussed to decrease mask induced eye dryness and changes in the eyelid microbiome.

Hyaluronic acid (HA) is the most common component of aesthetic fillers. Many formulations exist, each exhibiting properties that are manifestations of individual molecular modifications. The enzyme hyaluronidase degrades hyaluronic acid and can therefore be injected into soft tissue to reduce suboptimally placed HA fillers or to reverse local ischemic complications. The clinically available varieties of hyaluronidase may be derived from crude animal extracts or genetically engineered from recombinant human DNA. Different HA fillers are not uniformly dissolved by a single source hyaluronidase, and hyaluronidase from different sources may have varying efficacy in the degradation of HA. Previous studies of subsets of HA fillers and hyaluronidases have provided limited and often conflicting data regarding these differences, and a more comprehensive scientific study is needed. In this review, the authors describe commonly available formulations of HA and hyaluronidase and review all studies of HA-hyaluronidase interaction available via a PubMed and Google Scholar search from 2005 to present, exploring trends in the data. Factors determined to confer increased resistance to degradation included higher concentration of HA, higher crosslinking density, and status as monophasic versus biphasic. Fillers of the Juvéderm family were generally found to be more resistant to degradation than members of the Restylane family. Results are less consistent for Belotero Balance. No variety of hyaluronidase was consistently superior at dissolving any variety of HA filler. More research is needed to clarify these clinically relevant relationships.

Background: Retrobulbar injection of hyaluronidase is a proposed but unproven treatment for blindness induced by hyaluronic acid gel fillers. This study examines the viability of this treatment by determining whether hyaluronidase can diffuse through the dural sheath of the optic nerve to clear a filler-mediated occlusion of the central retinal artery. Methods: Six human cadaveric optic nerves were studied in vitro. One optic nerve was selected as a control and maintained at physiologic temperature, without any exposure to hyaluronic acid gel or hyaluronidase. Another optic nerve was randomly selected to simulate the filler-induced central retinal artery occlusion with subsequent retrobulbar hyaluronidase injection. To simulate a central retinal artery occlusion, this experimental nerve and additional controls were injected with hyaluronic acid gel. These hyaluronic acid gel–injected nerves were then either injected directly with hyaluronidase to establish a control for intraneural hyaluronidase exposure, or immersed in undiluted hyaluronidase to simulate retrobulbar hyaluronidase injection. To control for passive diffusion of hyaluronic acid gel from neural parenchyma, one nerve was immersed in saline. Following fixation, the nerves were grossly and microscopically assessed for the quantity and distribution of hyaluronic acid. Results: Intact hyaluronic acid gel was observed grossly and microscopically in the control optic nerves injected directly with filler and not with hyaluronidase. The control optic nerve injected with intraneural hyaluronidase exhibited partial digestion of the filler. Immersion in undiluted hyaluronidase led to no apparent gross or microscopic digestion of injected intraneural hyaluronic acid gel. Conclusion: Hyaluronidase does not demonstrate the ability to cross the dural sheath of the optic nerve, suggesting that retrobulbar hyaluronidase injection is unlikely to alleviate hyaluronic acid gel–mediated central retinal artery occlusion and blindness.