Researchers in Germany and at the Diabetes Research Center of New York's Albert Einstein College of Medicine report that a synthetic form of vitamin B1 prevents diabetic retinopathy in an animal model. They studied two groups of diabetic rats for 36 weeks, one on a diet containing the lipid-soluble thiamine derivative benfotiamine, the other untreated. The diabetic rats treated with benfotiamine did not develop any of the retinal damage found in the similar group of untreated rats.

Two of the by-products of cellular activity in diabetic retinopathy are the glycolytic metabolites glyceraldehyde-3-phosphate and fructose-6-phosphate. In diabetics, the increased availability of these metabolites activates three major biochemical pathways that are implicated in the pathogenesis of hyperglycemia-induced vascular damage: the hexosamine pathway, the advanced glycation end product formation pathway, and the diacylglycerol–protein kinase C pathway. The enzyme transketolase, which depends on vitamin B1 for its activity, converts these metabolites into harmless pentose-5-phosphates and other sugars. Benfotiamine increased the transketolase activity by 300 percent to 400 percent.

Unlike other substances being studied elsewhere, which impact one of these pathways, benfotiamine inhibited all three. The compound also prevented experimental diabetic retinopathy.

"The ability of benfotiamine to inhibit three major pathways simultaneously might be clinically useful in preventing the development and progression of diabetic complications," the researchers conclude. Their report was published in the online advance issue of Nature Medicine. Visit http://www.nature. com/naturemedicine.

Study Eyes Post-cataract Endophthalmitis
Japanese research suggests that a temporal corneal incision increases the risk of postoperative endophthalmitis and that the intraocular lens material does not affect the incidence of this complication. The study appeared in the January issue of the Journal of Cataract & Refractive Surgery.

The multicenter, prospective  study included patients who had small-incision cataract surgery from March 1998 to March 2001. The patients were randomized into three groups. In Group A, an acrylic IOL (MA60BM, Alcon) was implanted through a temporal corneal incision. In Group B, an acrylic IOL (MA60BM) was implanted via a superior sclerocorneal incision. In Group C, a silicone PMMA IOL (SI-40NB, Allergan) was implanted via a superior sclerocorneal incision. Each patient was followed for more than six months.
The final study included 3,831 eyes in Group A, 3901 eyes in Group B, and 3863 eyes in Group C. Postoperative endophthalmitis was diagnosed clinically in 11 eyes (0.29 percent) in Group A, two (0.05 percent) in Group B, and two (0.05 percent) in Group C.

Endophthalmitis proven by culture was found in nine eyes in Group A, two in Group B, and two in Group C. The relative risk of postoperative endophthalmitis proven by culture in Groups B and C was 4.6 times (P = .037) lower than in Group A.
J Cataract Refract Surg 2003;29:20–26.

Inspector General Suggests Cataract Cuts
If Congress or the Centers for Medicare & Medicaid Services follow the February recommendation of the Office of the Inspector General, surgeons who operate in either hospitals or ambulatory surgery centers might see their reimbursements drop.

According to the Outpatient Ophthalmic Surgery Society, which closely tracks proposed government regulation changes regarding ASCs, the OIG examined payment disparities in Medicare reimbursements for outpatient surgeries done in hospitals and ASCs. It based its recommendations on Medicare Payment Advisory Commission findings that Medicare pays ASCs more than hospitals for almost a third of the 2,500 procedures allowed in the ASC setting. It also found, though, that hospitals are reimbursed more than ASCs for the remaining procedures.

As a result of the findings, the OIG recommended that Medicare could save as much as $1 billion by reducing the hospital rates to those of the ASC in situations where the hospital's is higher, and that it could also save $100 million more if it cut the ASC rate to the level of the hospital reimbursement in the rest of the surgery situations where the ASC's is higher.

It's now up to Congress and CMS to decide how it will react to the report's findings.

A Closer Look at Alcohol Debridement
British researchers confirm what many refractive surgeons know: that alcohol delamination of the corneal epithelium before PRK or LASEK consistently results in a very smooth surface.

The researchers, reporting in Investigative Ophthalmology and Visual Science, sought to determine the plane of cleavage of the corneal epithelium and smoothness of underlying stroma, after alcohol debridement. The epithelial flap from six patients undergoing alcohol delamination of corneal epithelium before PRK and the epithelium and stroma from three eye bank donor eyes were fixed and processed for transmission and scanning electron microscopy. They studied the smoothness of the underlying stroma by SEM, and the plane of cleavage was determined by morphologic examination and morphometric measurements of basement membrane attached to the epithelial flap, using image-analysis software.

They determined the plane of cleavage to be at the hemidesmosomal attachments, including the most superficial part of the lamina lucida of the basement membrane. A very smooth stromal bed, ideal for PRK was seen in the stroma of all three eye bank donor eyes after alcohol delamination. They described a "consistently very smooth cleavage" that "leaves behind a very smooth surface, which is ideal for PRK. It also allows for an intact epithelial flap to be lifted as a sheet from the corneal surface and hence is ideally suited for the LASEK technique."
Invest Ophthalmol Vis Sci 2003; 44: 510-3

Congress Boosts 2003 Medicare Fees
A 4.4 percent cut in physician Medicare payments scheduled to go into effect March 1 has been defeated, according to the American Academy of Ophthalmology. The AAO, the American Medical Association and other specialties lobbied Congress to eliminate the cut as part of the Omnibus Appropriations Bill, signed into law by the president on February 20.
The passage of this provision eliminates this 4.4 percent cut, and the Centers for Medicare & Medicaid Services indicates payments will instead be increased by 1.6 percent this year.

The cuts scheduled for this year were in addition to physician Medicare payment cuts of 5.4 percent that went into effect in 2002. Estimation errors made in 1998 and 1999 contributed significantly to the scheduled negative updates predicted to total 20 percent by 2005.

"The language in this bill will permit CMS to correct these errors and improve Medicare payments by $54 billion over the next 10 years," said Cathy Cohen, vice president of Government Affairs for the AAO. "We are very proud of the immediate, positive impact for 2003, but there is still the potential for negative updates in the future. However, they will not be as steep. This gives us a better starting point for the academy's ongoing lobbying efforts."