APR 2015

EyeWorld is the official news magazine of the American Society of Cataract & Refractive Surgery.

Issue link: http://digital.eyeworld.org/i/493807

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Page 11 of 86

9 EW NEWS & OPINION W hat used to be the stuff of science fiction is moving its way into reality—a manned mission to Mars. As outlined in the NASA Authoriza- tion Act of 2010 and the 2010 U.S. National Space Policy, NASA is now developing ways to send humans to Mars around 2030. In addition to improving transportation capabili- ties and technologies, NASA and its partner organizations are looking to optimize the impact of space flight on the human body. Five ASCRS members are now part of a group that is looking into the ophthalmic impact of space travel: John Berdahl, MD (ASCRS Young Eye Surgeons Clinical Com- mittee member); Eugene de Juan Jr., MD; Richard L. Lindstrom, MD (ASCRS Foundation chair); Steve Schallhorn, MD (2007 ASCRS Binkhorst Lecturer); and Kuldev Singh, MD, MPH. These ASCRS members are part of a larger 10- person Vision for Mars Challenge, which first convened in November 2014 at the National Space and Biomedical Research Institute (NSBRI) in Houston. The challenge is an initiative of the NSBRI at Baylor College of Medicine, which partners with NASA. According to Baylor College of Medicine, the challenge's goal is to "help identify and advance med- ical technologies for ocular health in space through collaboration and funding support." The NSBRI and NASA recently uncovered many significant effects of space travel on astronauts, both inside and outside of ophthalmology. A NASA survey reported that as many as 60% of astronauts experienced vision issues after multiple tours on the Inter- national Space Station. One of the major issues being addressed is the risk of spaceflight-induced vision impairment and intracranial pres- sure (VIIP) syndrome. Read more in "Ophthalmology at zero gravity" on page 3 of this issue. "Primarily male astronauts at about 90 days in a micro-gravity en- vironment develop a syndrome that includes progressive hyperopic shift, posterior flattening of the globe, choroidal folds, and papilledema," said Dr. Lindstrom. "[For] a 500-day trip with the astronauts developing a significant ocular malady at 90 days is potentially a deal killer for the whole trip." Dr. Lindstrom serves as a con- nector in the ophthalmology, NSBRI, and NASA communities. Addition- ally, he is known for the out-of-the- box and entrepreneurial thinking that the NSBRI was looking for with the Vision for Mars Challenge partic- ipants. An example of this is his approach to VIIP syndrome. "I went through the data and pointed out that men seem more susceptible than women. It appears that slightly hyperopic people are more susceptible than slightly myo- pic people. It also seemed like bulky, heavy-massed individuals were more susceptible than lean-mass people," Five ASCRS members join Vision for Mars Challenge by Abbie B. Elliott ASCRS•ASOA Communications Manager continued on page 11 April 2015 ASCRS update In the journal ... Interface quality of different corneal lamellar-cut depths for femtosecond laser-assisted lamellar anterior keratoplasty Chenxing Zhang, MD, Matthew Bald, BS, Maolong Tang, PhD, Yan Li, PhD, David Huang, MD, PhD Investigators set out to consider how the cut depth of the corneal lamellar with the femtosecond laser affects the interface quality. Based on this, they hoped to determine a reasonable range of depth for such cuts when performing femtosecond laser-assisted lamellar anterior keratoplasty. When they considered how 20 de-epithelialized human cadaver corneas fared, they found that the cuts with the fewest ridges were the shallowest ones. The depth of these femtosecond cuts ranged from 31% of central stromal thickness to 48%. In a simulated procedure, investigators found that a graft cut to this 31% depth, using an inverted side-cut design, had a flush anterior junction and a smooth interface. They concluded that for femtosecond laser-assisted lamellar anterior keratoplasty, a depth setting of 31% might produce adequate surface quality. They also determined that even when the graft was thicker than the host lamellar-cut depth, there was good edge apposition with the inverted side-cut design. Influence of corneal asphericity on the refractive outcome of intraocular lens implantation in cataract surgery Giacomo Savini, MD, Kenneth J. Hoffer, MD, Piero Barboni, MD In this retrospective comparative case series, investigators considered how corneal surface asphericity affected refractive outcomes. 115 consecutive eyes having IOL implantation following cataract surgery were studied. All eyes were implanted with the AcrySof SA60AT lens (Alcon, Fort Worth, Texas). The Haigis, Hoffer Q, Holladay 1, and SRK/T formulas were used to calculate the intraocular lens power. Investigators determined that when it came to the error in refraction prediction, there was a statistically significant relationship with the Q-value. This was true for all of the formulas and devices. Myopic outcomes were associated with more negative Q-values, while hyperopic outcomes were linked to positive Q-values. Investigators concluded that when using third generation IOL power formulas, practitioners should take corneal asphericity into consideration since this influences the refractive outcomes of IOL implantation. Prevalence of cataract after collagen copolymer phakic intraocular lens implantation for myopia, hyperopia, and astigmatism José F. Alfonso, MD, PhD, Carlos Lisa, MD, Luis Fernández-Vega, MD, PhD, Dagoberto Almanzar, MD, Cari Pérez-Vives, MSc, Robert Montés-Micó, PhD How likely is a patient to develop a cataract after the implantable colla- mer lens (STAAR Surgical, Monrovia, Calif.) is placed in the eye? That's what investigators in this retrospective clinical study set out to deter- mine. In the study, each of the 3,420 eyes received 1 of 3 models of the pIOL—the V4, V4b, or V4C. At the 6-year follow up, explantation of the lens as a result of a cataract was required in just 15 eyes. Investigators reported that 8 of these patients were age 40 or older. When they con- sidered refractive error they found that just 3 had a pIOL power of less than –10.50 D, 4 had a power between –10.50 D and –13.5 D, and 14 had pIOL powers higher than this. No cataracts developed in eyes in which the latest models, the V4b or V4C, were used. Investigators determined that the overall incidence of cataract after implantation of the phakic IOL was low at the 6-year mark. They concluded that older patients and those with high refractive errors had a greater rate of cataract formation with the phakic IOL. April 2015 Dr. Lindstrom has been chosen as a member of the Vision for Mars Challenge. Source: Minnesota Eye Consultants

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