Snellen

Definitions

  • WordNet 3.6
    • n Snellen Dutch ophthalmologist who introduced the Snellen chart to study visual acuity (1834-1908)
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Usage

In literature:

Every school, private and parochial as well as public, should supply itself with the Snellen card for testing eyes.
"Civics and Health" by William H. Allen
V. 16/100, H. 2.5 D., Snellen IV-I/II; is the smallest type he reads at 3 to 7 inches.
"Schweigger on Squint" by C. Schweigger
In using Snellen's test card, place the pupil at the distance marked upon the card.
"Degeneracy" by Eugene S. Talbot
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In news:

The Snellen fraction, named for the ophthalmologist who devised it, signifies one's visual acuity at 20 feet (the top number) compared to standard vision (the bottom number).
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In science:

Snellen et al. (2002) have de fined a sample of bright GPS sources in the southern/equatorial sky, representing the counterpart of the sample of Stanghellini et al. (1998), although somewhat deeper.
Complete identification of the Parkes half-Jansky sample of GHz peaked spectrum radio galaxies
The selection criteria of the sample are described in detail in a previous paper (Snellen et al. 2002).
Complete identification of the Parkes half-Jansky sample of GHz peaked spectrum radio galaxies
The dotted line is the R-band Hubble relation as derived by Snellen et al. (1996a), the solid line is a linear least squares fit to the current data.
Complete identification of the Parkes half-Jansky sample of GHz peaked spectrum radio galaxies
Now that we have significantly increased the number of GPS galaxies with known redshifts, particularly around redshift z ∼ 1, it is interesting to review the R-band Hubble relation as previously discussed by Snellen et al. (1996a) and O’Dea et al. (1996).
Complete identification of the Parkes half-Jansky sample of GHz peaked spectrum radio galaxies
Although the source is located in a region with high galactic extinction, it is unlikely that this is the reason for the offset, since the object is also over two magnitudes fainter in K -band (de Vries et al. in prep.) than expected from the K -band Hubble diagram (as presented by Snellen et al. 1996b).
Complete identification of the Parkes half-Jansky sample of GHz peaked spectrum radio galaxies
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