Brillouin microscopy method measures corneal biomechanics in vivo

Sept. 13, 2017

The method measures corneal biomechanics in a non-contact, non-perturbative way to understand different corneal properties.

Content Dam Bow Online Articles 2017 09 Usc Roski Eye Institute Scarcelli Varma Hafezi Randleman Web

Seeking to add a new data point in the ongoing controversy in ophthalmology surrounding the impact of combined prophylactic corneal cross-linking (CXL) and LASIK flap creation, the University of Southen California (USC) Roski Eye Institute in Los Angeles demonstrated the lack of corneal biomechanical impact using a Brillouin microscopy method.

The research, led by USC Roski Eye Institute's J. Bradley Randleman, MD, along with University of Maryland collaborator Giuliani Scarcelli, Ph.D., measures the corneal biomechanics in a non-contact, non-perturbative way, allowing clinicians to understand the different corneal properties, such as shape and elasticity, in each individual patient in the research setting. By accounting for these properties in vivo, the Brillouin microscopy method may allow physicians to create personalized treatment plans for more precise identification of ectatic disorders, with the goal of preventing corneal transplantation or even blindness from conditions such as keratoconus, congenital brittle cornea syndrome, and pellucid marginal corneal degeneration.

(L-R) Giuliani Scarcelli, Dr. Rohit Varma, Farha Hafezi, and J. Bradley Randleman celebrate their breakthrough research on corneal cross-linking (CXL) and LASIK flap creation.

Many ophthalmic surgeons have debated the impact of the rapid CXL with LASIK flap creation called LASIK Xtra. It has been proposed that that the procedure is useful in protecting patients from developing ectasia and may even improve the stability of higher laser corrections. With their study, the USC Roski Eye Institute researchers could provide evidence to support the contrary.

"The novel Brillouin microscopy results offer new insight into whether there is a positive impact on patients who undergo the LASIK Xtra procedure," explains Randleman, a recognized international pioneer in CXL procedures and the director of USC Roski Eye Institute's Cornea, External Disease and Refractive Surgery. "Our findings have shown no significant increase in corneal stiffness after performing CXL combined with LASIK flap creation."

Applying broad applications, Randleman believes this technique can help vastly improve methods of diagnosing corneal ectatic disorders. Earlier diagnosis can potentially reduce or eliminate the need for corneal transplants and increase success in preserving sight.

Brillouin microscopy measures biomechanical properties of each layer the light passes through in the front of the eye, essentially performing a living biopsy of the cornea without touching or otherwise disturbing it. It measures natural light scattering that occurs when the cornea moves every millisecond because of constant, subtle changes in temperature. Earlier and more precise detection of corneal ectatic disorders can possibly help some patients avoid surgeries that can weaken the cornea and potentially avoid corneal transplantation.

Full details of the work appear in the Journal of Refractive Surgery.