Eyeworld

EW MEETING REPORTER 160 Reporting from the Asia-Pacific Academy of Ophthalmology (APAO) Congress, February 8–11, Hong Kong To perform PTK using the excimer laser, Dr. Shah said the surgeon first removes the epithelium mechanically. The laser "free scans" to remove scar tissue layer by layer. She noted that a laser with a PTK or transepithelial PRK mode or setting is necessary. The treatment should be interrupted frequently to moist- en the cornea and masking with fluid done to smooth irregularities. A large optical zone must also be selected, and the entire treatment zone is treated equally, mimicking the original shape of the cornea but at a lower depth so as not to induce an unplanned change in refraction. SMILE updates Now with more than 8 years of clinical experience, experts provided updates on SMILE—a still relative- ly new, rapidly evolving refractive procedure. Fengju Zhang, MD, Beijing, reported the results of a prospective observational study that aimed to identify factors affecting predict- ability in SMILE surgery on Chinese eyes. Their study found that pre- dictability in SMILE is positively correlated with the preoperative refraction, postoperative corneal epithelial hyperplasia, and stromal remodeling. In addition, measured lenticule thickness tended to be thinner than the estimated lenticule Dr. Oshika shared a case of a traumatic cataract in a 16-year-old from a blunt injury by a badminton shuttlecock. The PC was broken, but the PC tear did not extend to the equator, Dr. Oshika said. The lens material did not spread into the vit- reous or anterior chamber; it stayed in the capsular bag. The patient's parents requested a multifocal IOL, Dr. Oshika said, noting that he made no promises but said that he would try his best. Surgery was delayed for 2 months to allow the edge of the PC tear to undergo the wound healing/scar for- mation process. During that period, it was confirmed there was no crys- talline lens induced inflammation or drastic deterioration of the cataract. He implanted the multifocal IOL perpendicular to the direction of the PC tear, and the patient and parents were very happy with the good far and near visual acuity after surgery. All about anterior lamellar keratoplasty A symposium took a comprehensive look at deep anterior lamellar kera- toplasty (DALK). Among the issues discussed was the problem of corne- al tissue supply to support continu- ing treatment with the procedure. In a global survey, Wei Chen, MD, Hong Kong, said that 53% of patients have no access to corneal tissue for transplantation, and there- fore require an alternative solution. While a supply of suitable tissue remains necessary for the procedure, the advantage of DALK in this situa- tion is that it does not require viable endothelial cells. Dr. Chen discussed the "Use of Long-Term Preserved Corneas for DALK." Specifically, he described the use of glycerol-preserved corneas. Glycerol as a preservative contains antimicrobial and antiprotease prop- erties, maintains corneal structure, and is thus suitable for long-term storage of corneas for purposes not requiring viable cell layers. Comparing different methods of glycerol preservation, Dr. Chen said that "anhydrous glycerol preserva- tion without molecular sieves in a –78º C freezer was the best meth- od to obtain DALK-eligible tissues that were transparent and pliable." Examining graft survival and rejec- tion-free graft survival rates in cases using tissue preserved with this method, he further concluded that DALK using acellular glycerol-pre- served corneas may prevent allograft rejection and promote graft survival in high risk cases, among them eyes with herpes simplex keratitis. Rupal Shah, MD, Vadodara, India, described the use of photo- therapeutic keratectomy (PTK) for superficial corneal dystrophies—a procedure she said she has been successfully using for more than 2 decades. The procedure, she said, is pos- sible thanks to certain "special prop- erties" of the excimer laser, namely, the laser's ability to remove precise amounts of tissue leaving behind a smooth bed with no collateral dam- age to surrounding tissue and strong epithelial bonds in the tissue of the corneal bed. The advantages of PTK are that it is simpler, cheaper—sparing valu- able corneal tissue for other purpos- es—allows faster visual recovery, and can be done in some cases simulta- neously with refractive correction. The procedure, however, is limited to treating pathologies up to around 100 to 150 µm deep in the cornea, as it would otherwise leave the cor- nea too thin. March 2018 View videos from the 2018 APAO Congress: EWrePlay.org Soon-Phaik Chee, MD, discusses the diagnosis and management of CMV anterior uveitis. continued on page 162 Sponsored by

• Blank Page
• Blank Page (1)