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Changes in forward light scatter parameters as a function of refractive error in young adults
Background/aims
Some aspects of visual performance worsen with increasing myopia. Whilst the underlying causes are not always clear, reduction in retinal image quality is often attributed to structural changes in the posterior myopic eye. Forward light scatter, originating principally from the cornea and lens, is known to produce veiling glare which subsequently reduces retinal image contrast. It is therefore of interest to investigate whether forward light scatter varies with refractive error.
Methods
Thirteen young-adult subjects (18β25 years), with mean spherical errors (MSE Β± sd, D) RE, ββ1.69βΒ±β2.02 (range 0.38 to ββ4.75); LE, ββ1.91βΒ±β1.94 (range 0.50 to ββ4.63) underwent binocular assessment of forward light scatter using the AVOT light scatter test. Five glare annuli, with effective eccentricities ranging from 2 to 10Β°, were used to estimate parameters, k and n, which define the light scatter function of the eye. These were then used to calculate the area under the light scatter function (kβ²) and the total volume of light scatter (kβ³).
Results
Significant correlation was found between increasing myopia and kβ² values (RE, pββ0.05 for both eyes). Axial length was also not correlated with any of the light scatter parameters measured.
Conclusion
The preliminary data from this study provide evidence that some light scatter parameters may be correlated with refractive error. Further studies are needed to characterize how changes in the anterior media of the eye, and inclusion of a wider range of refractive errors, may affect forward light scatter
Interpreting 750 GeV diphoton excess in SU(5) grand unified theory
The ATLAS and CMS experiments at the LHC have found significant excess in the
diphoton invariant mass distribution near 750 GeV. We interpret this excess in
a predictive nonsupersymmetric SU(5) grand unified framework with a singlet
scalar and light adjoint fermions. The 750 GeV resonance is identified as a
gauge singlet scalar. Both its production and decays are induced by 24
dimensional adjoint fermions predicted within SU(5). The adjoint fermions are
assumed to be odd under symmetry which forbids their direct coupling to
the standard model fermions. We show that the observed diphoton excess can be
explained with sub-TeV adjoint fermions and with perturbative Yukawa coupling.
A narrow width scenario is more preferred while a simultaneous explanation of
observed cross section and large total decay width requires some of the adjoint
fermions lighter than 375 GeV. The model also provides a singlet fermion as a
candidate of cold dark matter. The gauge coupling unification is achieved in
the framework by introducing color sextet scalars while being consistent with
the proton decay constraint.Comment: Discussion added, conclusion unchanged; Matches published version in
Physics Letters
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