Records were selected from a data pool of myopic private practice patients to study the relation of refractive error change and keratometer power change in young adulthood. Selection was on the basis of three or more refractions and keratometer readings at and/or after 18 years of age. There were significant correlations between rate of myopia progression and rate of keratometer power change. Linear regression slopes of rate of refractive error change on rate of keratometer power change were in the neighborhood of 0.7. These findings were in contrast to the lack of correlation between myopia increase and corneal steepening in childhood myopia progression. Young adulthood myopia progression also appeared to be accompanied by a slight tendency toward a with-the-rule astigmatic shift.

Adolescent↗

PubMed1987

Ocular dominance and the interocular suppression of blur in monovision.

Presbyopic contact lens patients with monocular corrections (monovision) see clearly at all distances by virtue of an interocular suppression of anisometropic blur that occurs regionally between corresponding retinal areas. This suppression fails to occur with small high-contrast targets viewed under low luminance conditions. The effect of target size and contrast upon interocular suppression of blur was quantified by reducing contrast of a bright test spot, viewed binocularly while wearing various plus lenses monocularly, until the out-of-focus image was suppressed. The strength of interocular suppression was equivalent when the plus lens was before either eye. However, after subjects wore a plus lens over their nonsighting eye for one day, interocular suppression of blur became enhanced when the nonsighting eye was blurred, and it became reduced when the sighting eye was blurred. Successful monovision subjects suppressed blur at higher contrast levels than did unsuccessful subjects. These results suggest a possible clinical test for quantifying adaptation to monovision.

Adaptation, Physiological↗

PubMed1986

Service with a smile, and savings, too.

Explore the source record for details and available documents.

Consumer Behavior↗

PubMed1986

Serum vitamin E levels in the very low birth weight infant during oral supplementation.

A prospective study was initiated to monitor serum tocopherol levels in all infants admitted to Indiana University Medical Center with birth weights less than 1,500 g. These infants routinely receive 100 mg/kg/d of oral vitamin E (Aquasol E tocopherol acetate) every six hours. Levels are determined weekly or semiweekly using a modification of the fluorometric method of Hanson and Warwick. Vitamin E dosage is adjusted regularly to achieve levels greater than or equal to 3.5 mg/dL. During the 6 months of this study, a total of 76 patients had 567 serum measurements. Of these, 220 levels (38%) were greater than or equal to 3.5 mg/dL, 71 (13%) were greater than or equal to 5.5 mg/dL, and 15 (2.7%) were greater than 8 mg/dL. Serum tocopherol levels often (1) remained greater than or equal to 3.5 mg/dL for several days after oral supplementation was discontinued or (2) again became greater than or equal to 3.5 mg/dL on a reduced dosage of 25 to 50 mg/kg/d. These data indicate that infants weighing less than 1,500 g at birth who are receiving oral vitamin E supplementation at 100 mg/kg/d will have varied serum levels with a significant percentage exceeding 3.5 mg/dL.

Age Factors↗

PubMed1985

Prevalence and pattern of adult myopia progression in a general optometric practice population.

Longitudinal data on 559 myopic patients were collected from five optometry practices; adequate adulthood refractive data for analysis (three or more visits after 18 years of age) were available for 108 patients. Patterns of refractive change were evaluated subjectively and by linear regression analysis. Most myopes do not progress in young adulthood (about 20 to 25 years of age). Myopia progression during this age period is more common among males than among females. Adulthood myopia progression is related to an increase in corneal power.

Adolescent↗

PubMed1985

Performance characteristics of a hydrophilic concentric bifocal contact lens.

Hydrophilic bifocals designed to achieve simultaneous vision with a central distance zone and annular add zone were evaluated on 15 presbyopic subjects. Simultaneous vision was demonstrated for distance zone diameters from 2.25 to 3.25 mm. Both zones affected over-refraction at distance and near resulting in extra minus required for distance and extra plus required for near. On average, visual acuity was worse than with equivalent spectacle correction. Effects of a night viewing simulation were also studied.

Adult↗

PubMed1984

Determining Mycobacterium tuberculosis infection in high prevalence groups: a comparative study among Nigerian adults.

In populations where both tuberculosis and strong sensitization to nontuberculous mycobacteria are common, determining the proportion infected with M. tuberculosis is difficult. We skin tested 488 unvaccinated young Nigerian workers, typical of tropical populations having high prevalences of tuberculosis, with 4 low-dose Mantoux tests (PPD-RT-23, PPD-Tuberculin, PPD-Battey, and PPD-Gause) and with concentrated (2 mg/ml) PPD by the Heaf multiple-puncture method. Reactions (greater than or equal to 2 mm) to all 4 Mantoux sensitins (elicitins) unexpectedly were normal in distribution; however, the midpoint values (13 mm) of the RT-23 and PPD-T distributions were lower than the midpoints typically seen in groups of tuberculosis patients. Established methods for estimating the proportion tuberculous-infected (cutting point, dual-test, and curve-reconstruction) yielded a wide range, 32%-62%. Combining the 3 methods provided consistent estimates near 50%, despite interference due to strong sensitivity to PPD-B and especially to PPD-G in 80%-90%. PPD-T correlated well with RT-23 (r = .84), yet more closely resembled published PPD-S reaction distributions than did RT-23. All diagnostic-accuracy measures for the Heaf test, considering only grades 3 and 4 positive, exceeded 80%.

Adolescent↗

PubMed1984

Complete ocular component analysis by vergence contribution.

Traditionally, the components of ocular refraction are analyzed in surface powers and their linear separations in the eye. More recently it has been suggested that the refractive effects of these components are better studied in terms of their vergence contributions. This study presents an improved method of vergence analysis which takes into account the refractive status of the eye. Results show a significant interaction of all components and indicate that their relative contributions are dependent on refractive status.

Cornea↗