EyeWorld Asia-Pacific June 2017 Issue

3 June 2017 EWAP EDITORIAL EYEWORLD ASIA-PACIFIC EDITORIAL BOARD C HIEF MEDICAL EDITOR Graham BARRETT, Australia MEMBERS Abhay VASAVADA, India CHAN Wing Kwong, Singapore CHEE Soon Phaik, Singapore Hiroko BISSEN-MIYAJIMA, Japan Hungwon TCHAH, Korea ASIA-PACIFIC China EDITION Regional Managing Editor YAO Ke Deputy Regional Editors HE Shouzhi ZHAO Jialiang Assistant Editors ShenTu Xing-chao ZHOU Qi ASIA-PACIFIC INDIA EDITION Regional Managing Editor S. NATARAJAN Deputy Regional Editor Abhay VASAVADA ASIA-PACIFIC KOREA EDITION Regional Managing Editor Hungwon TCHAH Deputy Regional Editor Chul Young CHOI John CHANG, Hong Kong Johan HUTAURUK, Indonesia Kimiya SHIMIZU, Japan Pannet Pangputhipong, Thailand Ronald YEOH, Singapore S. NATARAJAN, India Sri GANESH, India YAO Ke, China Y.C. LEE, Malaysia T he most common refractive error that impacts on almost everyone as they enter middle age is presbyopia. There is a long history of attempts to address presbyopia with surgery, including limbal radial incisions and scleral implants, most of which have proved to be ineffective. Not surprisingly, the potential for a procedure to address the gradual loss of our ability to change focus from distance to near vision has attracted the attention of potential candidates and industry. Monovision with pseudophakia correction is an effective procedure and intraocular lens replacement with multifocals or extended depth of focus IOLs offer additional lens- based solutions. As an alternative, procedures to alter the power of the cornea have attracted the attention of many innovators. Monovision LASIK/PRK is widely practiced and a variety of laser refractive procedures that create a multifocal cornea have had modest success. More recently, there has been interest in corneal inlays to create a multifocal cornea. The attraction of the latter concept is that inlays are potentially reversible. Corneal inlays can alter the corneal curvature or produce their effect purely by altering the refractive index in the corneal stroma. Polysulfone inlays based on the latter concept were first considered by Peter Choyce to address high myopia. The polysulfone implants produced the desired correction but problems occurred due to disruption of corneal metabolism with scarring and corneal melts. My own interest in corneal inlays began in the 1990s when I developed a small diameter hydrophilic corneal inlay of approximately 2 mm. The concept was to address the limitations of biocompatibility by using a semipermeable hydrogel and a small diameter so as not to interfere with corneal metabolism. A small diameter inlay could create a bifocal cornea based on the refractive index of the material and I first implanted corneal inlays in 1996 to correct presbyopia. These inlays were well tolerated and patients achieved excellent unaided near vision. A multicenter study was begun with Chiron Ophthalmics with Richard Lindstrom as the medical monitor but the invention was not commercialized. Some 20 years later, interest in similar presbyopic inlays has rekindled and several devices including the Rainbow and Flexi-View micro lens are now available and discussed in depth in this issue. In addition, inlays based on the extended depth of focus created with a small aperture (Kamra) have been introduced. The limitations of current corneal implants relate to the compromise in quality of vision due to the multifocal nature of the correction or small aperture. In addition, the intracorneal location of inlays may react with inflammatory changes resulting in fibrosis. These inlays therefore require careful monitoring to allow removal before irreversible changes and impairment of vision occur. Modest monovision, either with presbyLASIK or with extended depth of focus IOLs offer viable alternatives and whether corneal inlays will become the dominant method to address presbyopia remains to be seen. Regardless, I am sure you will find the detailed coverage in this issue interesting. The “Age of Inlays” has indeed begun and it is fascinating to watch this field develop after my earlier work in developing corneal inlays to correct presbyopia in the 1990s. EWAP Graham Barrett Chief Medical Editorial EyeWorld Asia-Pacific The Age of Inlays