At Press Time

Huge Swedish Study of Cataract Outcomes

Data from a million cases has helped improve surgery results.

By Jerry Helzner, Senior Editor

■ Information derived from an unprecedented 18-year study conducted by the Swedish National Cataract Register and covering more than a million procedures has been instrumental in improving cataract surgery outcomes in that country. The data has been deemed so compelling in the area of endophthalmitis prevention that the proven Swedish protocol of using intracameral cefuroxime has been suggested as a European standard.

As reported in a recent issue of the Journal of Cataract & Refractive Surgery, the Swedish Cataract Register, founded in 1992, has compiled data for approximately 1.08 million procedures performed from 1992 through 2009, or about 95.6% of all cataract surgeries done in Sweden during that period.

Among the salient findings of this massive study:

■ Age at time of surgery. The mean age of surgery increased from 75.1 years in 1992 to 76.2 years in 1999, after which it slowly decreased to 74.9 years in 2009.

■ Second-eye surgery. The percentage of patients having cataract surgery in the second eye increased from 28.5% to 40.4% from 1992 to 2009.

■ Surgical technique. Surgical technique and type of IOLs became part of the Register in 1997. The early period marked the final transition to phacoemulsification and the widespread adoption of hydrophilic acrylic IOLs.

■ Sex of patients. The percentage of women patients remained relatively stable at approximately 66% from 1992 to 2000 and slowly decreased to 61% in 2009. Women tended to have surgery at a later age than men, possibly explained by differences in life expectancy between the sexes.

■ Biometry prediction error. The mean biometry prediction error has steadily decreased from approximately 0.7 D in 1995, the first year this metric was reported, to about 0.4 D in 2009. The improvement is attributable to more precise preoperative biometrical measurement and better surgical technique.

■ Endophthalmitis prevention. Suspected endophthalmitis cases following cataract surgery were added to the register in 1998. In that year, an incidence of 0.10% was reported. As of 1999, the type of prophylaxis used was also reported and it soon became clear that intracameral cefuroxime reduced the risk of endophthalmitis. Diagnostic routines were also improved. These steps were deemed instrumental in lowering the incidence of suspected endophthalmitis to 0.02% in 2009.

These stellar results led the European Society of Cataract and Refractive Surgeons to conduct its own randomized multicenter study to assess different prophylaxis modalities. The study confirmed the Swedish data.

Since 2002, the Swedish National Cataract Register has also been monitoring incision details, the use of an IOL injector and posterior capsule rupture in an attempt to determine if any or all of these factors were related to a higher or lower incidence of endophthalmitis. Posterior capsule rupture has since been associated with a higher risk of infection but IOL injectors could not be demonstrated to lower the risk.

■ Patient satisfaction. More than 90% of patients who filled out a questionnaire have consistently reported that their ability to perform daily activities has benefited as a result of their cataract surgery. The percentage of patients reporting increased capability in daily tasks has increased from 90.9% in 1995 to 93.3% in 2009.

In sum, the Swedish researchers who analyzed the mass of data conclude that the results reflect continuing and substantial positive developments in Swedish cataract surgery, primarily attributable to better surgical equipment and devices along with improved surgical technique. The researchers suggest that the 18-year data be used as a benchmark to drive further improvement.

Ophthalmic Surgery Bill Passes PA House

Scope of practice could be clearly outlined for the state's ODs.

By Samantha Stahl, Assistant Editor

■ A bill recently passed by the Pennsylvania House of Representatives has ophthalmologists hopeful that the definition of an ophthalmic surgeon will be clearly outlined, settling the ongoing dispute about what should be permitted in optometrists' scope of practice. The bill will now move on to the Pennsylvania Senate.

The Definition of Ophthalmic Surgery Bill, House Bill 838, aims to remove ambiguity from the law, says Kenneth Cheng, MD, president of the Pennsylvania Academy of Ophthalmology, which has actively promoted the bill for the last few years.

Dr. Cheng emphasizes the fact that this bill will not take anything away from the current scope of practice for the state's optometrists and any fears they may have about their future are unfounded.

“There is very specific language in the bill that clearly says that everything an optometrist can do the day before the bill passes, they will continue to be allowed to do the day after the bill is passed. It doesn't change anything in the current scope of practice of optometry.” Dr. Cheng notes that while many optometrists don't have any desire to expand practice beyond what they're doing now into surgery, this bill will help to minimize the “two tiers of optometry”—those who want to pursue surgery and those who do not.

Current Pennsylvania law states that optometrists are not allowed to perform surgery, but there is no definition of what constitutes surgery in the regulations. Pennsylvania House Bill 838 adds a Definition of Ophthalmic Surgery into the Optometric Practice Act.

Did the law recently passed in Kentucky, which greatly enlarged ODs' scope of practice, have anything to do with the Pennsylvania bill? Dr. Cheng says no. “We have been working on trying to achieve something like this for a number of years now. Even though PA law says an optometrist can't perform surgery, there is ambiguity in the law which should be removed.”

Efforts to expand scope of practice across multiple disciplines is a growing trend in many state capitols. Dan Briceland, MD, the AAO secretary for state affairs, attributes the rising public awareness of the scope issue to efforts by psychologists to prescribe psychotropic medications, which were widely covered in the media.

“However, ophthalmology has been addressing the problem of expanded scope for decades,” he says. “Increasingly, patients and insurance companies are paying closer attention to the issue because of the influence of healthcare reform on quality of care. Patient safety issues are now being raised as part of the public discussion on health care, which was not the case 20 years ago.”

Dr. Briceland insists that it is critical to inform legislators about the education and training of surgeons versus non-surgeons to help them better understand what those roles entail. Because there is so much variance in scope of practice laws from state to state and few legislators have a medical background, any time a surgeon's role can be more clearly defined, it helps legislators make better policy decisions.

“It is so important that this issue is discussed openly. This is about protecting the public and giving the best possible care for patients.”

FDA Goes Global on Product Safety

Worldwide coalitions of regulators to be formed.

■ The FDA has unveiled a new strategy to meet the challenges posed by rapidly rising imports of FDA-regulated products and a complex global supply chain in a report called the Pathway to Global Product Safety and Quality.

“Global production of FDA-regulated goods has exploded over the past 10 years,” said Commissioner of Food and Drugs Margaret A. Hamburg, MD. “In addition to an increase in imported finished products, manufacturers increasingly use imported materials and ingredients in their US production facilities, making the distinction between domestic and imported products obsolete. There has been a perfect storm—more products, more manufacturers, more countries and more access. A dramatic change in strategy must be implemented.”

The FDA report calls for the agency to transform the way it conducts business and to act globally in order to promote and protect the health of US consumers. Highlights of the report include four key elements needed to make the change:

1. The FDA will partner with its counterparts worldwide to create global coalitions of regulators focused on ensuring and improving global product safety and quality.

2. The coalitions of regulators will develop international data information systems and networks and increase the regular and proactive sharing of data and regulatory resources across world markets.

3. The FDA will build in additional information gathering and analysis capabilities with an increased focus on risk analytics and information technology.

4. The FDA increasingly will leverage the efforts of public and private third parties and industry and allocate FDA resources based on risk.

“FDA-regulated imports have quadrupled since 2000,” said Dr. Hamburg. “The FDA and our global regulatory partners recognize this new reality and realize we must work proactively and collaboratively to address the challenges we face. The FDA must further collaborate and leverage in order to close the gap between our import levels and our regulatory resources. This report is an important step in ensuring we are able to fulfill our critical public health mission.”

The new strategy also builds on changes already set in motion by the FDA. The FDA increased the number of foreign drug manufacturing inspections by 27% between 2007 and 2009 and has opened a series of international offices in key locations. The FDA has also collaborated with its counterparts in the EU and Australia on drug inspections, worked to harmonize certain aspects of drug regulation via the International Conference on Harmonization and joined the Pharmaceutical Inspection Cooperation/Scheme, which is an organization of the drug manufacturing inspectorates from 39 countries. The FDA and other global leaders are also creating an expanded global regulators forum for medical devices.

Research Digest

New & Noteworthy Journal Articles

Compiled by Andrew E. Mathis, PhD, Medical Editor

► IOP variation and modulation. How do variations in IOP measurements affect glaucoma outcomes? In a review article in the September 2011 issue of the American Journal of Ophthalmology, two physicians from the Jules Stein Eye Institute at UCLA seek an answer.

After summarizing several trials on IOP variation and damage to the optic nerve or compromise of the visual field, the authors note that IOP measurements are notoriously imprecise. There is also a risk of mistaking mere visual field variations for visual field progression.

Then, after reviewing theories of IOP variation and their possibly damaging effects, the authors review several articles on reducing variation of IOP. Here, topical prostaglandins have performed well in reducing the intervisit range of IOP variation. If modulation should fail to preserve the optic nerve, the patient might benefit from neuroprotective therapy. The authors also suggest lines for future research.

► Flexible dosing for AMD. A monthly dosing schedule for ranibizumab may not be feasible for some patients, due to cost or logistic problems. Thus, more flexible dosing regimens have been tested, with varying levels of success. In the July 2011 issue of Retina, a Spanish team of retinal physicians share the results of their prospective trial of ranibizumab using a treatment regimen offering injections as much as eight weeks apart.

Ninety eyes from 88 patients were included in the study. All patients were given a loading dose consisting of three initial monthly injections of 0.5 mg/0.05 mL ranibizumab. Then, depending on the activity of choroidal neovascularization in these eyes, follow-up injections were given at either four, six or eight weeks.

Median visual acuity improved by seven ETDRS letters at one month, increasing to 10 letters at three months and finishing at 12 months at a net gain of seven letters. Foveal thickness decreased significantly, and the mean number of injections given was 4.4 over 12 months; fully 40% of the patients needed only the three loading doses. In addition, visual acuity improvement was independent of the number of injections.

The Spanish team concludes that ranibizumab may be given on this flexible schedule effectively and safely. They do, however, concede that, because their study was not randomized and did not include a control group, the study was not as highly powered as it could have been.

► Corneal edema and IOP. The September 2011 issue of Cornea includes a study by scientists in China on the impact of post-phacoemulsification corneal edema on IOP, as measured by Goldmann applanation tonometry (GAT). While it may be the expectation that corneal edema will increase IOP, the opposite appears to be the case. However, the model of contact lens–induced edema commonly used to test the effect of edema on IOP, may be insufficient for evaluating the effect of acute edema on IOP.

Researchers measured five variables—IOP, central corneal thickness, corneal hysteresis, corneal resistance factor and radius of corneal curvature—pre- and postoperatively.

A total of 136 patients were enrolled in the study, and on postoperative day 1, central corneal thickness had increased from 534 ±23 µm to 589 ±45 µm, a mean increase of 10.3%. GAT IOP decreased significantly, as did corneal hysteresis. There was a steeper mean radius of corneal curvature on the first postop day, and there was no significant change in corneal resistance factors.

The most significant finding, however, is that the effect on GAT IOP of corneal edema appeared to be the opposite of contact lens–induced edema, lowering instead of raising the intraocular pressure. However, the authors did also identify a threshold level of change in corneal thickness (around 9.5%), above which GAT IOP was no longer lowered by increased edema. In short, some edema can lower IOP, but too much will have little or no effect. This study may have implications for IOP control in glaucoma patients.

► Refractive error in children with Down syndrome. Among the many issues that arise as children with Down syndrome get older is a tendency toward refractive error that increases more swiftly and severely than children who do not have Down syndrome. To understand better the development and distribution of refractive errors in children with Down syndrome, a group of professors at the School of Optometry and Vision Sciences at the University of Cardiff in Wales investigated these issues. They report their findings in the August 2011 issue of the British Journal of Ophthalmology.

In the Welsh study, 182 children with Down syndrome were allotted to 15 age-specific study groups, covering ages one to 15. All underwent a refractive examination using Mohindra retinoscopy, which measures refraction quantitatively using three values, M, J0 and J45. Twelve of these children, for whom there were available data for 15 years, were studied for a longer period to assess their long-term refractive development.

The children studied were hypermetropic, with wide variation in refractive errors. Further, there was a statistically significant prevalence of oblique astigmatism, which increased with age and reached 45% among teenage patients.

The authors indicate that their findings provide further evidence of the failure of the emmetropization process in children with Down syndrome. They also indicate that later astigmatic findings may be due to the cumulative effect of the significant epicanthic folds found in these patients.