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News
IFIS Given Prominent Attention in General Medical Literature
In May, the Journal of the American Medical Association (JAMA) published a Canadian study that showed that, in addition to causing surgical complications due to intraoperative floppy iris syndrome (IFIS),1 tamsulosin (Flomax; Boehringer Ingelheim Pharmaceuticals, Inc., Ridgefield, CT) increases patients' risk of developing serious complications following cataract surgery.2 Tamsulosin is an alpha-adrenergic receptor blocker indicated for the treatment of benign prostatic hyperplasia (BPH). According to Bell et al, of nearly 100,000 men undergoing cataract surgery during a 5-year period, those taking tamsulosin had a 2.3 times higher risk of severe postoperative complications such as retinal detachment and lost lens fragments.2
The JAMA study was the first on IFIS to be published in the general medical literature, and an editorial written by ophthalmologist Alan H. Friedman, MD, accompanied the report. Shortly thereafter, the June issue of American Family Physician, the official peer-reviewed journal of the American Academy of Family Physicians, featured a special invited editorial on IFIS by David F. Chang, MD. The journal has one of the largest circulations (175,000) in North America. Dr. Chang, who along with John Campbell, MD, first described IFIS in 2005,1 is a clinical professor at the University of California, San Francisco, and is in private practice in Los Altos, California.
In his editorial, titled, "Why BPH treatment can complicate cataract surgery," Dr. Chang reviewed the most important clinical information about IFIS for prescribing physicians. He cited peer-reviewed studies that compared the incidence of IFIS with tamsulosin versus other alpha-1 antagonists commonly used to treat BPH. He also cited key findings from the 2008 ASCRS survey, which revealed, among other important data, that 90% of respondents believed that IFIS was more common with tamsulosin than with nonselective alpha-1 antagonists. Additionally,
Dr. Chang pointed out that silodosin (Rapaflo; Watson Pharmaceuticals, Inc., Corona, CA), the newest FDA approved drug for the treatment of BPH symptoms (October 2008), most closely resembles tamsulosin by being selective for the alpha 1A receptor subtype. The new drug's propensity to cause IFIS, however, is not yet known.3
Calling attention to the joint ASCRS and AAO educational update statement for primary care physicians released in July 2008, Dr. Chang encouraged prescribing physicians to consider involving an ophthalmologist before initiating treatment with alpha-1 antagonists in patients who have cataracts. Furthermore, he advised prescribing doctors to remind patients taking systemic alpha-1 antagonists, or those who have in the past, to report this history to their ophthalmologist before having eye surgery.
"This editorial, coupled with the lead article in JAMA 2 weeks ago, will hopefully go a long way in educating our primary care colleagues who do the first-line prescribing for BPH," wrote Dr. Chang in an e-mail to Cataract & Refractive Surgery Today. "The JAMA study documented complications—retinal detachment, lost lens fragments, and severe inflammation—that nonophthalmologists will recognize as being serious, and it also reported that complications were not as high in patients taking non-selective alpha-1 antagonists."
Because the JAMA study was widely reported in the press, the ASCRS and the AAO issued a new joint patient advisory on tamsulosin and other alpha-blockers. "The press articles reported that Flomax more than doubled the complication rate in the Canadian study, but didn't address what patients should do if they are already taking, or need to take, an alpha blocker," explained Dr. Chang. "The purpose of the joint advisory was to update and reinforce our previous recommendations to patients."
The ophthalmic organizations advise patients to report any history of alpha blocker use to their ophthalmologist and to be aware that these drugs may make eye surgery more difficult. However, the advisory also attempts to reassure patients that, if their ophthalmologist knows about their alpha blocker history, the success rate of cataract surgery is still excellent and they need not otherwise delay or avoid recommended cataract surgery.
To read Dr. Chang's editorial on IFIS and share it with your primary care colleagues, consult the June 1 issue of American Family Physician at www.aafp.org/online/en/home/publications/journals/afp.html.
FDA Clears Device for Testing Tear Osmolarity
The FDA cleared the TearLab Osmolarity System (TearLab Corporation [formerly OccuLogix, Inc.], San Diego, CA) for clinical use in the United States. The TearLab System uses a novel lab-on-a-chip approach that requires less than 50 nL of fluid to measure osmolarity. The 510(k) clearance allows TearLab Corporation to market the device to certain US clinical facilities immediately. TearLab received the CE Mark for its TearLab Osmolarity System in 2008 and is currently marketing the device in 14 countries globally.
STAAR's Epiphany Injector System Granted 510(k) Approval for NTIOLs
The Epiphany Injector System (STAAR Surgical Company, Monrovia, CA) received FDA 510(k) approval for use with STAAR's Affinity Collamer Three-Piece and Elastimide Silicone Aspheric New Technology IOLs (NTIOLs). According to the company, the Epiphany delivers the IOL in a planar fashion through a 2.8-mm incision and thus provides a controlled release of the lens' haptics. The Epiphany is intended for single use, and surgeons can reportedly perform twist or push insertion techniques. The first shipments of the Epiphany Injector System are scheduled to begin this month, and a full US market release is expected in August.
Disposable, Preloaded Capsular Tension Ring Available in the United States
The FDA recently approved the EyeJet Capsular Tension Ring (Morcher GmbH, Stuttgart, Germany) for marketing in the United States. FCI Ophthalmics, Inc. (Marshfield Hills, MA), is the US importer and distributor of this product.
The EyeJet Capsular Tension Ring is a disposable injector preloaded with one of three type 14 capsular tension rings (14, 14A, or 14C). Each preloaded injector is packaged in a peel-open, contoured, sterilized container. The EyeJet Capsular Tension Ring is available in both a left and right version to accommodate the surgeon's desired direction of implantation. The left model is for implantation in a counter-clockwise direction, whereas the right model is for clockwise insertion. According to a news release, the EyeJet Capsular Tension Ring is most useful for cataract procedures involving zonular dehiscence, pseudoexfoliation, or other anomalies of the capsular bag.
Phase 3 Clinical Development Plan for Blepharitis Therapy Announced
InSite Vision Inc. (Alameda, CA) recently met with the FDA to review the results from a phase 3 clinical trial of ISV-502 and discuss plans for further phase 3 evaluation of the drug, according to a news release.
ISV-502, or AzaSite Plus, is a topical combination of 1% azithromycin and 0.1% dexamethasone for the treatment of blepharitis. ISV-502 is formulated with InSite Vision's proprietary drug delivery vehicle DuraSite, a gel-forming drop, which reportedly extends the retention time of the drug relative to conventional eye drops.
In December 2008, InSite Vision completed a phase 3 clinical trial of ISV-502 in patients presenting with the signs and symptoms of bacterial infection and inflammation of the eye. In the three-armed study, investigators compared the anti-inflammatory and antimicrobial effects of ISV-502 with those of either dexamethasone or AzaSite (azithromycin ophthalmic solution 1%), InSite Vision's topical antibiotic eye drop for the treatment of bacterial conjunctivitis. According to the company, ISV-502 improved clinical outcomes compared with dexamethasone or AzaSite alone, but the difference did not achieve statistical significance in all arms of the trial. ISV-502 was also reportedly safe and well tolerated.
Based on the FDA's recommendation, InSite Vision will conduct a pilot study to demonstrate ISV-502's ability to delay the exacerbation and/or recurrence of acute episodes of blepharitis. InSite Vision may seek another meeting with the FDA upon completion of the pilot study to consider the final phase 3 trial's protocol. Additionally, the FDA stated that it would be willing to consider a Special Protocol Assessment for ISV-502 prior to the start of the next phase 3 clinical trial. According to a company official, InSite Vision will seek a partner for the phase 3 program and commercialization of ISV-502.
Xibrom Appears to Improve Dry Eye Signs and Symptoms
The results from a proof-of-concept phase 2 clinical study of Xibrom (bromfenac 0.09%; Ista Pharmaceuticals, Inc., Irvine, CA) suggest that the topical, nonsteroidal anti-inflammatory drug improves dry eye signs and symptoms.
The phase 2 study enrolled 38 patients who exhibited the signs and symptoms of moderate dry eye disease. Patients underwent lissamine green and fluorescein testing before their first treatment with Xibrom and at days 14, 42, and 52. Ocular Surface Disease Index scores were also evaluated.
According to a company news release, Xibrom statistically significantly improved the signs and symptoms of dry eye, as demonstrated by lissamine green and fluorescein testing when compared with patients' baseline scores. The lissamine green test revealed statistical significance for Xibrom versus the patients' baseline scores as early as day 14. These improvements were sustained through day 52. Patients also achieved statistically significant improvements in subjective symptoms as measured by the Ocular Surface Disease Index. Adverse events were reportedly uncommon, and there were no serious ocular or systemic harmful events.
The FDA approved Xibrom in 2005 as a twice-daily formulation for the control of ocular inflammation and pain after cataract surgery. A recent phase 3 trial found that a once-daily formulation of the drug is also effective for this indication. Ista plans to perform a confirmatory phase 3 trial of once-daily Xibrom later this year.
Preclinical Trial Using Human Corneal Epithelial Cells Produces Positive Results
International Stem Cell Corporation (ISCO; Oceanside, CA) reportedly achieved positive early results in preclinical trials designed to test whether corneal epithelial cells grown in vitro from unfertilized human eggs can improve the outcome of PRK. According to a company news release, the first-stage animal trials demonstrated that ISCO's corneal epithelial cells, manufactured by ISCO's subsidiary, Lifeline Cell Technology (Walkersville, MD), encouraged corneal defects to heal. ISCO plans to seek the FDA's approval to test the efficacy of these corneal epithelial cells to improve healing after corneal surgery.
ISCO is collaborating with Paul H. Chen, MD, the developer of the cell transfer technology used in the trials. Dr. Chen is an eye surgeon at North County Laser Eye Associates in Carlsbad, California, and he is on staff at Scripps Memorial La Jolla and Scripps Encinitas Hospitals in California.
Dry Eye Prevalent Among US Men
A recent cross-sectional study estimated the prevalence of and risk factors for dry eye among men aged 50 years and older.1 Investigators evaluated survey responses from participants in the Physicians' Health Studies I (N = 18,596) and II (N = 6,848). The study showed that the prevalence of dry eye increased with age, from 3.9% among men aged 50 to 54 years to 7.67% among men aged 80 years and older (P<.001). High blood pressure was associated with a higher risk of dry eye, as was benign prostatic hyperplasia and the use of antidepressants, antihypertensives, and other medications to treat the condition. The researchers estimated that 4.34% of men (or 1.68 million) aged 50 years and older in the United States are affected by dry eye. The condition is reportedly expected to affect more than 2.79 million men by 2030.
FDA Cautions Against Misleading LASIK Advertisements
In a letter sent to eye care professionals in May, the FDA said it has received complaints that some providers of LASIK "fail to inform consumers of the indications, limitations, and risks associated with LASIK procedures and the approved lasers used for the LASIK procedures."
"Advertising and promotional materials for FDA-approved lasers used during LASIK procedures must be truthful, properly substantiated and not misleading," wrote Timothy Ulatowski, author of the letter and director of the Office of Compliance, Center for Devices and Radiological Health.
Mr. Ulatowski directed eye care professionals to devices@FDA, a Web site that lists all of the FDA-approved lasers for LASIK as well as the intended uses and risks, warnings, precautions, side effects, and contraindications associated with the devices. LASIK providers are urged to align their advertising with the information on this Web site.
According to a news release, the FDA shares the oversight of LASIK advertising with the Federal Trade Commission. If the FDA believes that LASIK advertising is misleading, it can issue a warning, impose fines, or even refer the case for criminal investigation.
SBK and PRK Achieve Equivalent Visual Acuity
Despite initially significant differences in postoperative visual acuity between eyes that underwent sub-Bowman's keratomileusis (SBK) and PRK, 6-month data suggest that both refractive procedures produce equivalent visual results over the long term.1
The prospective, randomized study enrolled 50 patients (100 eyes) at two sites. Each patient underwent PRK in one eye and SBK in his or her contralateral eye. The mean preoperative spherical refraction was -3.66 D, and the mean cylinder was -0.66 D for all eyes. In the SBK eyes, investigators used the 60-kHz IntraLase femtosecond laser (Abbott Medical Optics Inc., Santa Ana, CA) to create a flap with a diameter of 8.5 mm and an intended thickness of 100 µm. Eyes in the other group underwent 8.5-mm ethanol-assisted PRK. All eyes underwent correction for myopia, with or without astigmatism, with the Ladarvision 4000 (Alcon Laboratories, Inc. Fort Worth, TX).
At the 1-month follow-up visit, 88% of the SBK eyes achieved a UCVA of 20/20 or better compared with 48% of the PRK eyes (P<.0001). At 3 months, the UCVA in the PRK group improved (92% SBK versus 90% PRK 20/20 or better; P>.5). By 6 months after surgery, there was further equalization between the groups, with 94% of the PRK eyes and 92% of the SBK eyes achieving a UCVA of 20/20 or better (P=.63).
At 1 and 3 months, the SBK group had fewer higher-order aberrations (coma and spherical aberration; P².05). However, at 1, 3, and 6 months, there was no statistically significant difference in spherical aberration or vertical and horizontal coma between the groups.
"The significant finding of the study was that early on, the SBK eyes were much quicker to recover, experienced less pain and dry eye, and saw much better," wrote Stephen G. Slade, MD, in an e-mail to Cataract & Refractive Surgery Today. Dr. Slade is a surgeon at Slade and Baker Vision in Houston and a coauthor of the study. "There were no complications. Also of interest was that there was no significant difference in corneal rigidity or biomechanical effect between the two groups. We concluded that there is no advantage in strength or safety with SBK compared with PRK, but the patient achieves useful vision and maximum comfort much sooner."
Study Assesses Fluid Loss Through Incisions During Phacoemulsification
A prospective study showed that removing the chopper after using it during coaxial phacoemulsification significantly reduced fluid loss and improved chamber stability.1
Investigators evaluated fluid loss during 105 consecutive cataract extractions. Incisional leakage was defined by the difference between the total volume of irrigating fluid used and the volume aspirated by the phaco machine. According to the study's authors, the mean incisional leakage was 127 ±60 mL (range, 10 to 300 mL), with a significant positive correlation between the duration of the operation and actual phaco time (P<.0001). The mean percentage of incisional leakage was 67% ±11% (range, 20% to 89%). Furthermore, the mean amount of fluid lost was 75% in operations performed with the chopper in situ throughout phacoemulsification and 59% when the chopper was removed after all segments were chopped (P<.005).
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