EyeWorld Weekly Update, January 23, 2017

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January 23, 2017
Volume 22 , Number 3

Telescope implant in studies for IOL exchange

The Implantable Miniature Telescope (IMT, VisionCare Ophthalmic Technologies, Saratoga, California) will be evaluated for safety and efficacy in an IOL exchange in pseudophakic patients with end-stage age-related macular degeneration (AMD), according to the company. In the study, the IOL will be exchanged for the IMT. The IMT is currently approved for use only in phakic patients aged 65 years or older with end-stage AMD, and is indicated for monocular implantation. Stephen Lane, MD, Stillwater, Minnesota, said that while cataract surgery is often performed in end-stage AMD patients, studies show those patients "do not experience an appreciable improvement in their visual acuity, post-cataract surgery."

First PDEK procedure performed

Ahad Mahootchi, MD, Eye Clinic of Florida Same Day Surgery Center, Zephyrhills, Florida, performed the first pre-Descemet's endothelial keratoplasty (PDEK) corneal transplant procedure to rely on an eye bank prepared and preloaded Descemet's membrane graft, according to a news release. PDEK transplantation uses a single-cell layer of corneal tissue. The procedure makes a transplant possible for people with complex cases, but the tissue traditionally has taken doctors hours to prepare. The Lions Eye Institute for Transplant & Research (Tampa, Florida) prepared the tissue. According to Dr. Mahootchi, pre-loaded tissue may allow more surgeons to adopt the PDEK procedure as it offers additional reliability in unrolling the tissue in vitrectomized eyes or in eyes with prior YAG capsulotomy.

New developments may help eliminate ROP worldwide

A mini-symposium on retinopathy of prematurity noted more than 90% of premature infants even with severe ROP can expect a favorable outcome in Western countries, while under-resourced areas lack trained staffing, functional equipment, and a rudimentary understanding of ROP in its myriad forms, according to the Journal of the American Association for Pediatric Ophthalmology and Strabismus. Telemedicine and vascular endothelial growth factor (VEGF) inhibitors are two new modalities that are showing promise, the symposium authors noted. Anti-VEGF bevacizumab has potential, but delayed recurrence of ROP after bevacizumab treatments does occur (usually 5-10%). The key will be proper case selection (timing), careful injection, and appropriate long-term follow-up (at least 65 weeks adjusted age). Further work in determining which anti-VEGF, at what dose, and the benefits/possible side effects is needed, the authors said.

iPSCs able to restore visual function in murine models

Researchers at the RIKEN Center for Developmental Biology, Kobe, Japan, have shown that retinal transplants derived from induced pluripotent stem cells (iPSCs) can restore visual function in mice, the group announced. Their study shows that neurons in the implanted retinal sheets integrate well with the host, respond to light, and send their signals to the brain as judged by behavioral experiments. Masayo Takahashi and colleagues used a mouse model for end-stage retinal degeneration in which the outer nuclear layer of the retina is completely missing. This is an important issue because in clinical practice this type of therapy would most likely target end-stage retinas in which the photoreceptors are dead and the next neurons up the chain do not have any input. While the model mice that lacked a photoreceptor layer in their retinas could not learn to associate anything with light before surgery, they could after the transplant, provided that a substantial amount of the transplant was located in the correct place. This means that not only did the new cells in the retina respond to light, but the information traveled to the brain and could be used normally to learn, the group noted.

RESEARCH BRIEFS

  • Little difference among five tonometers was found, with all providing reliable intraocular pressure (IOP) readings in keratoconic eyes regardless of the presence of corneal ring segments, according to C. Mendez-Hernandez and colleagues. In their observational case series, a total of 147 eyes (147 patients) with keratoconus had IOPs measured using the Tono-Pen XL (Reichert Technologies, Depew, New York), Pascal dynamic contour tonometer (Ziemer Ophthalmic Systems, Port, Switzerland), Icare Pro (Icare, Raleigh, North Carolina), Ocular Response Analyzer (ORA, Reichert Technologies), and Goldmann applanation (GAT) in random order. Smallest mean IOP differences with GAT measurements in eyes without and with ring segments, respectively, were detected for Icare Pro (0.2 [2.9] mm Hg and 0.4 [3.0] mm Hg, P=0.914) and the greatest differences for ORA Goldmann-correlated IOP (5.8 [3.3] mm Hg and 6.0 [3.1] mm Hg, P=0.363). Best agreement with GAT was shown by Icare Pro and worse agreement by ORA corneal-compensated IOP. All but the dynamic contour tonometer readings were influenced by central corneal thickness, yet these measurements were affected by the presence of ring segments (P=0.017) and corneal astigmatism (P=0.030). Corneal curvature only affected ORA Goldmann-correlated IOP (P=0.029). The study is published in the Journal of Glaucoma.
  • Diquafosol sodium ophthalmic solution 3% (DQS) is effective in treating dry eye disease after cataract surgery with improvement of visual function, according to Y. Inoue and colleagues. This was a post-hoc analysis of a previously conducted randomized clinical study on 59 eyes from 42 patients (17 males and 25 females, aged 72.6±8.0 years) with verified or suspected dry eye at 4 weeks after cataract surgery who were randomly assigned to DQS or artificial tears (AT) for the postop evaluation time frame. After 4 weeks of instillation, tear break-up time (BUT) significantly increased (P=0.001) compared with pre-instillation values in the DQS group, but not in the AT group. This increase in BUT in the DQS group was significantly greater than in the AT group (P=0.014). Corneal and conjunctival fluorescein staining scores after instillation significantly improved compared with pre-instillation values in the DQS group (P=0.018). In higher order aberrations, the cornea aberration changed from an upward curve (a sawtooth pattern) to an almost constant value (a stable pattern) in the DQS group, but not in the AT group. In fluctuation index and stability index, there were no significant changes in either group; however, both were significantly lower in the DQS group than in the AT group (both P=0.004). The study is published in Clinical Ophthalmology.
  • Femtosecond laser-assisted cataract surgery did not yield better visual or refractive outcomes than conventional phacoemulsification cataract surgery, according to Sonia Manning, MD, and colleagues. They compared the visual, refractive, and adverse outcomes of femtosecond laser-assisted cataract surgery and conventional phacoemulsification cataract surgery at cataract surgery clinics in nine European countries and Australia (femtosecond-assisted) and 18 European countries and Australia (conventional). The study matched 2,814 femtosecond-assisted cases to 4,987 conventional phacoemulsification cases. Femtosecond-assisted surgery compared as follows to conventional phacoemulsification: posterior capsule complications, 0.7% versus 0.4%; postoperative logMAR CDVA, 0.05 (6/6−3) versus 0.03 (6/6−2); worse postoperative CDVA at follow-up (by five letters or more), 1.0% versus 0.4%; CDVA 0.3 (6/12) or better, 96.3% versus 97.1%; absolute biometry prediction error, 0.43 D versus 0.40 D; within ±0.5 D of target, 72% versus 74.3%; and postoperative complications, 3.4% versus 2.3%. The study is published in the Journal of Cataract & Refractive Surgery.

NEW PRODUCT BRIEFS

  • Bausch + Lomb (Bridgewater, New Jersey) introduced the Zen RC Scleral Contact Lens. It is designed to fit normal corneas and features SmartCurve technology, which simplifies the fitting process by giving eyecare professionals the ability to modify to the desired parameters.

EYEWORLD WEEK Online is edited by Stacy Majewicz and Michelle Dalton.

EyeWorld Week Online (ISSN 1089-0319), a digital publication of the American Society of Cataract and Refractive Surgery and the American Society of Ophthalmic Administrators, is published every Friday, distributed by email, and posted live on Friday.

Medical Editors: Eric Donnenfeld, MD, chief medical editor; Rosa Braga-Mele, MD, cataract editor; Clara Chan, MD, cornea editor; Nathan Radcliffe, MD, glaucoma editor; and Vance Thompson, MD, refractive editor.

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