Glaucoma Lessons From the Deep

What do whale eyes reveal about the disease?

Jacqueline Jeon-Chapman, BS, and David Fleischman, MD, MS, FACS

Glaucoma Today

Key Takeaways Whales, squid, and deep-sea fish illustrate a central principle: Ocular survival under pressure depends on structure. The future of glaucoma therapy may require ophthalmologists not only to lower pressure but also to better understand, and perhaps one day modify, the tissues that determine how that pressure is experienced. Research is being conducted to explore whether altering the biomechanical environment of the optic nerve head could alter its susceptibility to IOP-related injury. A few years ago, while I (D.F.) was watching The Wild Kratts children’s show with my daughter, I learned that sperm whales routinely dive thousands of feet below the ocean surface and hold their breath for more than an hour while hunting giant squid in near darkness. While my daughter focused on the on-screen battle between whale and squid, I found myself wondering: How does a mammalian eye tolerate such an extreme environment without developing glaucoma? At depths approaching 6,000 feet, external hydrostatic pressure is immense. The lesson, however, is not that whales experience IOP in the way humans with glaucoma do. Rather, the eye is a biomechanical organ, and nature has solved the problem of pressure tolerance in multiple ways. DIFFERENCES IN THE CORNEA AND SCLERA Whale eyes can withstand extreme conditions in part because of differences in the cornea and sclera. Cetacean corneas and sclerae are substantially thicker than those of humans (Figure).

Psychogenic Amblyopia

Here’s how to differentiate this condition from similar types of vision loss—and how to manage these patients.

Maureen D. Plaumann, OD, PhD, FAAO, Dipl AAO, Ann M. Morrison, OD, PhD, FAAO, Dipl AAO

Modern Optometry

Tecnis PureSee IOL Fully Launched in the US

Eyetube

Johnson & Johnson expands the availability of its latest Tecnis lens; Bayer completes its acquisition of Perfuse Therapeutics, expanding its presence in ophthalmology; and ophthalmic leaders discuss how to navigate the current regulatory environment of the FDA. Learn more about your ad choices. Visit megaphone.fm/adchoices