EyeWorld Asia-Pacific December 2013 Issue

47 EWAP DEVICES December 2013 Dr. Lee said Anwar’s big bubble technique is his “go-to procedure” for keratoconus, although he does note his conversion rate to PK is about 15-20%, which he hopes to decrease. Dr. Lee uses a Hanna trephine (Moria, Antony, France) to a depth of about 350 microns; using a 30-gauge needle he introduces air into the posterior corneal stroma through the trephination site. “I remove the anterior stroma first (referred to as bulk keratectomy),” he said, using a crescent blade to remove the top 30–40% of the stroma. He uses Healon (Abbott Medical Optics, Santa Ana, Calif., USA) in the center of the cornea, “followed by a stab incision into the air pocket after placement of viscoelastic on the surface stroma to slow the release of air and decrease risk of perforation.” Lastly, he’ll use a blunt dissector to separate Descemet’s from the overlying stroma followed by removal of stroma down to bare Descemet’s membrane. Where his technique differs is in the creation of the big bubble, he continued. “I give myself two attempts to create the big bubble,” he said. “I’ll put the needle into the stroma after trephination, but if I’m not successful there, I’ll perform my bulk keratectomy and replace the needle into the remaining posterior stromal tissue to attempt the big bubble again.” Dr. Beltz uses a microkeratome enabled ALK with or without cone collapse as described by Prof. Busin if the corneal thickness is 380 microns or greater. “This technique has the advantage of reproducibility, and the anterior cap of a DSAEK donor can generally be used, hence allowing for two recipients from one donor tissue,” she said. She reserves manual dissection, big bubble DALK, mushroom keratoplasty or PK for thin, steep, or irregular corneas or those with full thickness opacities. Because of the high quality donor tissue in Australia, she always has a PK quality tissue on standby “except for my microkeratome cases.” For big bubble DALK, Dr. Beltz uses a 27-gauge needle. “[I] attempt to pass this with the bevel down as deeply as possible into the corneal stroma prior to injection of the big bubble. I have not had increased success with specially designed injection cannulas, although they have become quite popular,” she said. Dr. van Meter uses Fugo blades (Medisurg, Norristown, Pa., USA), and recommends surgeons get a “deep dissection, as leaving extra stroma in the bed will decrease the patient’s vision down the road.” Keys to acceptance Currently, no prospective, randomized studies exist to elucidate which technique is better, Dr. van Meter said. “It’s good to know how to perform DALK, but endothelial keratoplasty provides a faster visual recovery,” he said, but thinks the advantages of preserving endothelial cells and graft integrity while reducing the risk of rejection may help DALK increase its acceptance. For the time being, though, “the advantages do not outweigh the disadvantages.” Dr. Beltz said case selection may be the single most important factor “for reliable use of the microkeratome. For the beginning surgeon, I would advise selecting cases with central corneal thickness of 380 microns or more,” she said, and uses the CB microkeratome system (ALTK, Moria), which employs a gas turbine-driven microkeratome to perform both the recipient as well as the donor lamellar cut with the use of an artificial chamber. She recommends using the “zero” suction ring to reliably create a host cut of 9.0 mm diameter. Dr. Lee only converts to full thickness surgery if he sees a macroperforation during the stromal portion of the removal. He prepares his own tissue and waits until he knows he has a successful big bubble before prepping the donor tissue. “I typically use an 8.5 mm trephination and punch it right at the beginning of the case, only to peel away Descemet’s membrane and endothelium after recipient stromal removal has been successful,” he said. The advent of the femtosecond laser means “the trephination is going to be perfect,” he said, which may increase the likelihood of surgical acceptance. EWAP Editors’ note: Drs. Beltz, Lee, and Van Meter have no financial interests related to this article. Prof. Busin has financial interests with Moria. Contact information Beltz: jacquelinebeltz@mac.com Busin: mbusin@yahoo.com Lee: wblee@icloud.com Van Meter: wsvanmeter@aol.com necessary. Evaluating the anatomy to ensure patients aren’t rubbing their eyes is helpful.” Sjögren’s patients Although most dry eye patients do not have a systemic component, patients with Sjögren’s often complain of severe dry eye (and dry mouth). “I am much more aggressive in using plugs earlier in patients with Sjögren’s since they don’t tend to respond as much with topical cyclosporine 0.05%, and many times they are incapacitated by their dry eye condition,” Dr. Epitropoulos said, but added she still prescribes topical cyclosporine 0.05% and aggressively treats blepharitis “to improve the quality of the tear film before plugging.” Dr. Talley-Rostov will consider plugs in Sjögren’s patients, but also advises considering cautery. “If the patient presents with Sjögren’s, I’m likely to go to plugs sooner than with the typical woman in her 40s or 50s who does a lot of near work and needs dry eye management,” Dr. Talley- Rostov said. “All dry eye patients need education—they need to know that while we can treat their issues, we cannot cure them.” EWAP Editors’ note: Dr. Epitropoulos has financial interests with Allergan (Irvine, Calif., USA) and Bausch+Lomb (Rochester, NY, USA). Dr. Talley-Rostov has financial interests with Allergan and Bausch+Lomb. Contact information Epitropoulos: aepitrop@columbus.rr.com Talley-Rostov: ATalleyRostov@nweyes.com Treating - from page 45