Researchers at Brigham and Women"s Hospital, Harvard Medical School, conducted a randomized double-masked, placebo-controlled trial to determine whether vitamin E supplementation decreases the risk of age-related cataract in women.

The study included 39,876 apparently healthy female health professionals aged 45 years or older. Participants were assigned randomly to receive either 600 IU of natural-source vitamin E on alternate days or placebo; they were followed up for presence of cataract for an average of 9.7 years. Main outcome measures included age-related cataract defined as an incident, age-related lens opacity, responsible for a reduction in best-corrected visual acuity to 20/30 or worse, based on self-report and confirmed by medical record review.

No significant difference was evident between the vitamin E and placebo groups in the incidence of cataract (1,159 vs. 1,217 cases; relative risk [RR], 0.96; 95 percent confidence interval [CI], 0.88 to 1.04). In subgroup analyses of subtypes, no significant effects of vitamin E were evident on the incidence of nuclear (,1056 vs. 1,127 cases; RR, 0.94; 95 percent CI, 0.87 to 1.02), cortical (426 vs. 461 cases; RR, 0.93; 95 percent CI, 0.81 to 1.06) or posterior subcapsular cataract (357 vs. 359 cases; RR, 1.00; 95 percent CI, 0.86 to 1.16). Results were similar for extraction of cataract and subtypes. Investigators found no modification of the lack of effect of vitamin E on cataract by baseline categories of age, cigarette smoking, multivitamin use or several other possible risk factors for cataract.

The data indicate that 600 IU natural-source vitamin E taken every other day provides no benefit for age-related cataract or subtypes.

Wavefront data are expressed in micrometers and referenced to the pupil plane, but current methods to map wavefront error lack standardization. Many use normalized or floating scales that may confuse the user by generating ambiguous, noisy or varying information. In this study, investigators from Louisiana State University"s ophthalmology department present an absolute scale that combines consistent clinical information with statistical relevance for improved diagnostics using wavefront error mapping.

Investigators conducted a retrospective analysis of wavefront error data from historic ophthalmic medical records. They used a topographic modeling system for topographical examinations of 120 corneas across 12 categories. Corneal wavefront error data in micrometers from each topography map were extracted at eight Zernike polynomial orders and for three pupil diameters expressed in millimeters (3 mm, 5 mm and 7 mm). Both total aberrations (orders 2 through 8) and higher-order aberrations (orders 3 through 8) were expressed in the form of frequency histograms to determine the working range of the scale across all categories. The standard deviation of the mean error of normal corneas determined the map contour resolution. Researchers based map colors on corneal topography color standards and on the ability to distinguish adjacent color contours through contrast. They produced an absolute color scale that encompassed a range of +/-6.5 microns and a contour interval of 0.5 microns. They plotted all aberrations in the categorical database with no loss of clinical information necessary for classification. In the few instances where mapped information was beyond the range of the scale, the type and severity of aberration remained legible.

The authors believe that their absolute scale facilitates the determination of the severity of aberrations present compared with a floating scale, particularly for distinguishing normal from abnormal levels of wavefront error. They suggest that the new color palette makes it easier to identify disorders, and they believe this corneal mapping method can be extended to mapping whole-eye wavefront errors.