EyeWorld Asia-Pacific September 2012 Issue

49 September 2012 EWAP DEVICES Brazil-based group shines spotlight on technology and methods to prevent ectasia W hen it comes to corneal biomechanics, there’s no more intense research going on than in the Rio de Janeiro Corneal Tomography and Biomechanics Study Group. In its field, the group has been heralded for pushing forward new thinking, which ultimately leads to better corneal surgery products, safer ophthalmic surgery, and happier patients. Members of the group have won recent awards from ASCRS, ESCRS, and ISRS for their work on corneal thickness profiles, tomography, corneal biomechanics, and enhanced screening capabilities. Ultimately, a considerable amount of what we currently understand about corneal biomechanics—and some controversy, too—begins with this small group in Brazil. Early beginnings Just as Renato Ambrosio Jr., MD, Visare Personal Laser, Clinica Oftalmologica Dr. Renato Ambrosio Jr., Rio de Janeiro, Brazil, was finishing medical school, his father passed away. But tucked away on VHS tapes were some important lessons for the young Dr. Ambrosio. “I saw a video that he recorded,” said Dr. Ambrosio, scientific coordinator of the study group. “He had recorded a course on RK in 1982. [The lesson involved] the cornea having important characteristics when one is performing RK—for instance, thickness. Even in those early times, they were considering that, and those ideas really influenced me over the years.” Family ties are what brought Dr. Ambrosio to the world of corneal biomechanics. But it was his wholehearted passion for the subject that led him to found the study group in 2005. Bruno M. Fontes, MD, in need of a subject for his PhD thesis, soon joined the group, as did others. The group’s work initially focused on generating tomographic data for both healthy and keratoconic patients in the Brazilian population. It also generated valuable information regarding corneal hysteresis. With a series of new paper publications, the group was finding statistically different values for healthy and keratoconus groups. Importantly, it found that as people get older, lower values of corneal hysteresis appear. “There is low hysteresis for both strong and fragile corneas, for different reasons,” said Dr. Fontes, in private practice, Rio de Janeiro, Brazil. “But there is a significant overlap.” Meanwhile, the group was finding new parameters yielding more insights into what differentiates healthy and normal corneas. “We are still working to improve sensitivity and specificity,” Dr. Fontes said. “What we need right now for refractive surgery evolution is a trustworthy way to measure corneal strength to detect pre-operatively patients who are at higher risk to develop post-surgical ectasia.” Additionally, Dr. Fontes said it’s important to be able to measure individual corneal stress to modulate laser energy to treat each patient individually. Strong corneas, for example, might need more laser energy to shape them correctly. Fragile corneas might need less energy. At the heart of corneal biomechanics: Tomography and a study group by Matt Young EyeWorld Contributing Editor Ectasia after LASIK with unrecognized risk factors based on standard screening (front surface topography and CCT) Enhanced screening Source: Renato Ambrosio, Jr., MD continued on page 54