Week in review: COVID complication, hummingbird hues, pigmentosa puzzle

A weekly roundup of ophthalmic news from around the web.

Could orbital emphysema be another possible complication of COVID-19? A case study in the latest issue of Ophthalmology details a 74-year-old patient with severe COVID-related pneumonia who underwent orotracheal intubation for respiratory failure. He was put on increased levels of positive end-expiratory pressure and prone positioning. Upon supination, physicians discovered subcutaneous emphysema extending from the patient’s chest to face, unilaterally in the conjunctiva and bilaterally around the eyelids (image above). Ophthalmic exams did not reveal any orbital compartment syndrome or vascular occlusion. Ophthalmology

Patients with wet AMD could be missing critical care during the pandemic. In a study published as a preprint on medRxiv, data from 4 U.K. ophthalmology centers revealed that new referrals for wet AMD dropped by an average of 72% during the month of April. The authors estimate that the lack of care could lead to a 25% relative decrease in the number of eyes with driving vision at 1 year. University College London

A novel light-activated drug continues to show promising preliminary outcomes, according to new phase 1b/2 data presented at ARVO 2020. Lead investigator Prithvi Mruthyunjaya, MD, said that intravitreal AU-011 showed favorable results in safety, tumor control and vision preservation in the vast majority of patients. Common side effects included inflammation and IOP spikes, which resolved with steroids and topical ocular antihypertensives. The company plans to initiate a phase 2 study to assess suprachoroidal administration of AU-011 later this year. Aura Biosciences

Hummingbirds are small, mighty and can detect a spectrum of colors “humans cannot even imagine,” according to a new PNAS study of some 6,000 hummingbirds. After 3 years of studying these creatures, researchers reveal that hummingbirds can distinguish a variety of nonspectral colors in addition to spectral hues like humans. “Even when the colors looked the same to us—for example, when the birds had to choose from a feeder colored UV-green and one that was simply green—they could see the difference,” explained first author Mary Stoddard, PhD. Her findings suggest hummingbirds can see up to 35% of bird plumage and plant colors in nonspectral hues that are undetectable to the human eye. These findings may extend to others in the animal kingdom, including all tetrachromatic day birds as well as some fish, reptiles and invertebrates. National Geographic

A series of new studies is challenging the current dogma on the underlying cause of retinitis pigmentosa 59 (RP59). Previously classified as a congenital disorder of glycosylation, experiments on 2 recent RP59 mouse models now suggest otherwise. Neither model had defects in protein glycosylation and only one showed retinal degeneration while the other only had very subtle physiological defects. Adding to the confusion, a third mouse study suggests retinal pigment epithelium pathology may significantly contribute to retinal degeneration. These findings point to a more complex mechanism for the disease than originally hypothesized, explained lead investigator Steven Fliesler, PhD. “Without knowing the underlying mechanism of RP59, it would be more difficult to develop targeted therapies to prevent, retard, or cure the disease.” University of Buffalo