Eyeworld Daily News

EW SHOW DAILY 16 ASCRS News Today Sunday, May 7, 2017 need to understand what they are looking at in an OCT scan and why. OCT offers a cross-sectional image of the anterior segment and its different anatomic structures. It helps the eye surgeon distinguish the corneal air/tear interface, tear film layer, corneal epithelium, stroma, and endothelium. It is also important in identifying changes in the iris and anterior chamber, vi- sualizing the natural lens, checking artificial lens placement, and finding conjunctival/scleral lesions. Ms. Armstrong explained that it is important to repeat OCT scans in different meridians to localize defects and dislocations, for in- stance, as a horizontal scan may not visualize the same structures as a vertical scan, or the meridians in between. She said that working with the Zeiss Visante (Carl Zeiss Meditec, Jena, Germany) offers the advan- tage of longer wavelengths, which allows deeper penetration of tissues, resulting in higher resolution of im- ages, as well as penetration into the chamber angle. Chamber angle im- aging is central to glaucoma patient diagnosis, showing the eye doctor if the chamber angle is opened or closed. Ms. Armstrong stressed commu- nication with the physician regard- ing scan patterns and protocols. She explained that artifacts are common on OCT, such as shadowing, air bub- bles, corneal reflexes, and comput- er-generated warping and striations, and should be recognized as such. OCT is instrumental for eval- uating the outcomes of new cor- neal transplant techniques such as Descemet's stripping endothelial keratoplasty (DSEK), according to Dr. Cohen. This technique removes the diseased endothelium and Descem- et's membrane (30 µm) and inserts a donor endothelium and stroma (150 µm) in their place. The technique avoids the complications of pene- trating keratoplasty. Once the donor cornea is implanted and positioned, OCT is used to demonstrate proper positioning. It can also show donor corneal health by demonstrating swelling of the donor or the recipi- ent cornea, as well as the interface. OCT scans measure corneal thick- ness, reveal donor failure, and graft malpositioning. Dr. Cohen described the many uses of OCT in visualizing corneal scars and ocular surface tumors. Scans help identify infectious keratitis and fungal corneal ulcers by showing inflammatory areas and edemas within the cornea and surrounding tissues. Pre- and postoperative OCT scans of anterior chamber depth help mark changes following surgery. Also, visualizing the corneal shape helps distinguish between disease states like pellucid marginal corneal degeneration and keratoconus. The use of real-time OCT in femtosecond laser cataract surgery allows for highly precise OCT-guided surgery. It identifies relevant ana- tomic parts of the anterior segment and surgical safety zones, along with incisions, lens fragmentation, and the capsulotomy size. EW Editors' note: Ms. Armstrong and Dr. Cohen have no financial interests related to their comments. by Stefanie Petrou Binder, MD, EyeWorld Contributing Writer and Kenneth Cohen, MD, both from Chapel Hill, North Carolina, who think that a firm understand- ing of OCT is integral to ophthalmic surgery. Technicians and nurses S peaking at a Technicians & Nurses session on the many uses of OCT in ophthalmic surgery were Sarah Armstrong, CRA, OCT: Understanding its many applications in the anterior segment Ms. Armstrong explains the many applications of anterior segment OCT. ASCRS•ASOA News Today Watch ASCRS•ASOA News Today in many Los Angeles hotels for the latest meeting highlights Hotel Channel Number Omni 61 Westin Bonaventure 82 LA Hotel 1 JW Marriott + Ritz Carlton at Convention Center 72 Sheraton Grand 80 Marriott Courtyard LA LIVE 57 Residence Inn 57 Millennium Biltmore Hotel 87

• Cover