Volume 5, Number 20
Monday, May 23, 2005



In this issue: (click heading to view article)
Editorial: Medical Errors
Heritability of Refractive Error and Familial Aggregation of Myopia in an Elderly Population
Association Between Intensity of Posterior Capsule Opacification and Visual Acuity
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Editorial: Medical Errors

This week, USA Today reported that despite efforts, an estimated 98,000 deaths occur annually due to medical errors. One could argue whether this is an accurate number, but that sidesteps the issue: that such a number of errors could still occur in this age of heightened awareness, significant threat of litigation, advances in technology and the like.

Undoubtedly, unforeseen complications will always occur, and realistically there is little we can do to avoid them completely. But opportunities exist that will allow us to reduce many errors. Physicians, hospitals and other healthcare providers must be allowed to work together toward solutions in an environment that is not contaminated by a constant threat of a malpractice claim. Let’s face it: we want to do the right thing to ensure the safest and best care possible, but we cannot accomplish this if we are distracted by the "legal eagles."

Potentially, the solutions rest in advances in technology, including electronic medical records, sufficient and fair payments by insurance providers to allow for the training and hiring of skilled and adequate staffs of healthcare workers, vertical integration of healthcare systems and old-fashioned dedication to the cause. Realistically, it can be accomplished; practically, it will not be done overnight.

Stephen E. Pascucci, MD
Medical Editor
[email protected]

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Heritability of Refractive Error and Familial Aggregation of Myopia in an Elderly Population

Researchers at Johns Hopkins and the NIH’s National Human Genome Research Institute conducted a study aimed at determining the heritability of refractive error and the familial aggregation of myopia in an older population.

A total of 759 siblings (mean age, 73.4 years) in 241 families were recruited from the Salisbury Eye Evaluation (SEE) Study in eastern Maryland. Investigators determined refractive error by noncycloplegic subjective refraction, if presenting distance visual acuity was greater than or equal to 20/40; or lensometry, if best corrected visual acuity was greater than 20/40 with spectacles. Participants were considered plano (refractive error of zero) if uncorrected visual acuity was greater than 20/40. Investigators used preoperative refraction from medical records for pseudophakic subjects. They calculated heritability of refractive error using multivariate linear regression and estimated it as twice the residual between-sibling correlation after adjusting for age, gender and race. They used logistic regression models to estimate the odds ratio (OR) of myopia, given a myopic sibling relative to having a nonmyopic sibling.

Results showed that the estimated heritability of refractive error was 61 percent (95 percent confidence interval [CI]: 34 percent to 88 percent) in this population. The age-, race- and sex-adjusted ORs of myopia were 2.65 (95 percent CI 1.67 to 4.19), 2.25 (CI 1.31 to 3.87), 3.00 (CI 1.56 to 5.79), and 2.98 (CI 1.51 to 5.87) for myopia thresholds of -0.50, -1.00, -1.50 and -2.00D, respectively. Neither race nor gender was significantly associated with an increased risk of myopia.

SOURCE: Wojciechowski R, Congdon N, Bowie H, et al. Heritability of refractive error and familial aggregation of myopia in an elderly American population. Invest Ophthalmol Vis Sci 2005;46(5):1588-92.
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Association Between Intensity of Posterior Capsule Opacification and Visual Acuity

The Medical University of Vienna’s Department of Ophthalmology investigated the correlation between the change in visual acuity and the difference in objective posterior capsule opacification (PCO) scores before and after neodymium:YAG (Nd:YAG) laser capsulotomy.

Researchers examined 40 pseudophakic eyes of 35 patients with PCO of varying intensity before and after Nd:YAG laser capsulotomy. They determined visual acuity using the Early Treatment Diabetic Retinopathy Study (ETDRS) chart at 4 m and the Holladay reading chart at 40 cm; they measured pupil diameter under reading conditions each time. They took digital retroillumination images of the posterior capsule, and they evaluated the corresponding area inside the pupil using the Automated Quantification of After-Cataract (AQUA) automated PCO analysis program. The change in visual acuity and difference between PCO scores before and after Nd:YAG laser capsulotomy were calculated for all eyes.

The mean AQUA score (scale 0 to 10) was 3.56 before and 0.13 after Nd:YAG laser capsulotomy. The mean ETDRS visual acuity score (logMAR scale) was 0.28 and -0.07, respectively. The correlation coefficient between the differences in PCO score and distance visual acuity was 0.61 and near visual acuity, 0.62. The authors concluded that objective PCO assessment by automated image-analysis systems is a valuable and clinically relevant method for clinical studies of the development and prevention of PCO.

SOURCE: Buehl W, Sacu S, Findl O. Association between intensity of posterior capsule opacification and visual acuity. J Cataract Refract Surg 2005;31(3):543-7.
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BRIEFLY
  • FAVORABLE RESULTS ANNOUNCED IN TTT4CNV CLINICAL TRIAL. IRIDEX recently announced that additional follow-up data confirmed a significant clinical benefit in a group of patients with wet age-related macular degeneration (AMD) who were treated with the company’s transpupillary thermotherapy (TTT) laser protocol when compared to the placebo control group in the TTT4CNV clinical trial. The updated results confirmed and expanded upon the initial results reported in February 2005 that a subgroup of patients in the study with baseline visual acuity of 20/100 or worse benefited from TTT treatment. Within the TTT4CNV trial, about 41 percent of patients had baseline vision of 20/100 or worse. At 12 months following treatment, 23 percent of TTT-treated eyes in this subgroup improved vision by one or more lines and 14 percent of TTT-treated eyes improved vision by three or more lines, compared with none of the eyes in the placebo treated control group. At 18 months, there was a two-line benefit in preserving vision in this subgroup when compared to placebo-treated eyes.
  • MACUGEN APPROVED IN CANADA FOR TREATING NEOVASCULAR AMD. Health Canada has granted approval (Notice of Compliance) for Eyetech Pharmaceutical’s Macugen (pegaptanib sodium injection) for the treatment of subfoveal choroidal neovascularization secondary to neovascular age-related macular degeneration (AMD). Macugen is the first therapy indicated in Canada for the treatment of subfoveal neovascular AMD, regardless of lesion subtype or size; it was approved following a priority review by Health Canada. Macugen was approved in the United States in December 2004 and launched in January 2005. Eyetech and Pfizer Inc co-promote Macugen in the United States; Eyetech has granted Pfizer exclusive rights to commercialize Macugen in countries outside the United States, including Canada, pursuant to a royalty-bearing licensing agreement.
  • DNA DRUG DELIVERY AVAILABLE FOR TREATING EYE DISEASES. Copernicus Therapeutics, Inc., recently announced their development of a new proprietary non-viral nucleic acid nanoparticle technology that can efficiently introduce DNA into cells of the retina and other optic tissues. In collaborative studies with Dr. Muna Naash at the University of Oklahoma Health Sciences Center, the company achieved gene transfer efficiencies of up to 99 percent; the results were announced at the recent ARVO meeting. According to the Copernicus, the data shows that the technology can efficiently introduce genes into the eye for treatment of retinitis pigmentosa, macular degeneration, diabetic retinopathy and viral infections. Copernicus has also completed a successful clinical trial that involves using the technique to develop a therapy for cystic fibrosis.
  • CLARIFICATION. Last week’s Review of Ophthalmology Online included a news brief about the Centers for Medicare and Medicaid Services giving patients the option to pay privately for presbyopia-correcting IOL implantation during cataract surgery. The story mentioned Eyeonics’ Crystalens and Alcon’s Acrysof ReStor IOLs, but neglected to cite AMO"s ReZoom multifocal IOL, which provides vision for distance, intermediate and near ranges. ROO regrets the omission.


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