Neuropsychological dysfunction, mood disturbance, and emotional status of munitions workers.

The objective of this study was to compare the neuropsychological function, emotional status, visual function, and illness prevalence of 265 former munitions plant workers (M age = 56.7 years, M years of education = 12.07; 201 African American, 64 White) exposed to organic solvents for an average of 17.03 years with that of a group of 77 unexposed controls (M age = 51.3 years, M years of education = 13.07; 30 African American, 47 White). Neuropsychological tests were selected from the World Health Organization Neurobehavioral Core Test Battery, Wechsler Adult Intelligence Scale-III (WAIS-III), and Wechsler Memory Scale-III (WMS-III) and also included the Brief Symptom Inventory, Profile of Mood States, Beck Anxiety Inventory, and Beck Depression Inventory. Vision tests included the Lanthony d-15 color vision, the Vistech Contrast Sensitivity, and the Snellen. The exposed group showed greater deficits than the controls in verbal learning (WMS-III Logical Memory I Learning Slope and Word Lists I Recall), visuomotor tracking speed (Cancellation H, WAIS-III Digit Symbol-Coding) and psychomotor function (Dynamometer and Grooved Pegboard), and dysfunction in emotional status, illness prevalence, and visual function. African American workers reported higher levels of exposure than Whites. Exposure relations demonstrated increased neuropsychological dysfunction with increased exposure.

Macular edema reduces B cone sensitivity in diabetics.

A simple clinical test of B cone pathway sensitivity shows that a group of 45 diabetics (of which 31 have VA >/= 20/20) are 40 times less sensitive than a group of 57 normals. By contrast, the diabetic group is less than 2.2 times less sensitive than the normals for R and/or G cone pathway sensitivity. The selective B cone sensitivity loss is seen even in patients who have no macular edema; however, the presence of edema is associated with significantly greater sensitivity loss. Age differences between the groups cannot account for the differences seen between normals and diabetics.

Early color vision changes in age-related maculopathy.

Little is known about the early natural history (prior to visual acuity loss) of age-related maculopathy (ARM). We report here results from noninvasive psychophysical tests designed to evaluate aspects of chromatic and achromatic visual processing in patients with ARM known to be at increased visual risk. These tests results indicate that prior to a visual acuity loss the sensitivity of the B-Y chromatic pathway and the achromatic system is reduced. This reduction increases over time and accelerates at or near the time of clinically manifest signs. At that time it also includes sensitivity loss in the R-G chromatic pathway.

Effective powers of flexible contact lenses.

Predictions of effective powers of flexible contact lenses including tear lenses, or assuming alignment, are compared with actual equivalent sphere effective powers of 12 low-minus and 2 high-plus lenses. The assumption of a tear lens improves accuracy of prediction.

Approximate tear volumes under flexible contact lenses.

The quantification of tear volume trapped under a flexible contact lens in situ is important for an understanding of both optical and physiological lens behavior. Mathematical treatment is used to calculate the flexed back radii of flexible contact lenses in situ from the various hypotheses available. For each hypothetical radius the tear volume under the lens is calculated. The method is limited in accuracy due to several underlying assumptions. Twelve lens situations are analyzed, and the results indicate a tear volume of the order of 10 microliters.

Changes in back radius of soft contact lenses when flexed.

Mathematical statements are made for the various hypotheses describing the change in radius of curvature of the back surface of a flexible contact lens as it flexes. These hypotheses may now be tested for validity in predicting both optical and physiological behavior of real contact lenses in situ.

Direct readout of spectral sensitivity for clinical and research purposes.

The application of spectral sensitivity measurements to clinical problems has been limited by the complexity of calculating the corrections for nonlinearity and non-neutrality of the neutral wedge and for the quantum intensity of the test beam. Asimple electronic system is described which performs all these calculations automatically, as the subject makes the sensitivity setting, and records the sensitivity on an XY plotter. A range of 5 log units is covered with an accuracy of 0.05 log units.