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anatomic and physiologic outcomes of the auto-transplanted retinal flap in our series suggest that this technique may offer an effective option for treating recalcitrant MH. Further studies are warranted.
The human eye exhibits large amounts (2.5 diopters) of longitudinal chromatic aberration (LCA). Its impact on polychromatic image quality, however, has been shown experimentally and by computer modeling to be small or absent. We hypothesized that modest changes in pseudophakic LCA created by higher and lower Abbe number materials will have little or no impact on polychromatic image quality in pseudophakic eyes.
Using published chromatic and monochromatic aberration data from pseudophakic eyes and higher and lower Abbe number materials (37 and 55), we computed monochromatic point spread functions for 21 wavelengths across the visible spectrum. After weighting by either the RGB spectra of a liquid crystal display or by a flat white spectrum, they were weighted by the human spectral sensitivity function (V
) before being added to generate polychromatic PSFs.
In the absence of monochromatic aberrations, the reduced LCA due to higher Abbe number intraocular lens (IOL) materials resulted in a reduction of 0.08 diopters in the mean defocus generated by LCA. Orelabrutinib in vitro At the retinal plane, the higher Abbe number pseudophakic model produced improvements in polychromatic modulation transfer functions (MTFs) similar to those generated by a 0.05 diopter reduction in spherical defocus. When monochromatic aberrations were added to make the model more representative of actual pseudophakic eyes, the differences in image quality became sub-threshold for human vision or disappeared completely.
The anticipated gains in polychromatic image quality from employing higher Abbe number IOL materials with reduced LCA do not materialize in plausible aberrated models of pseudophakic eyes.
The anticipated gains in polychromatic image quality from employing higher Abbe number IOL materials with reduced LCA do not materialize in plausible aberrated models of pseudophakic eyes.
Vitiligo is a common skin condition affecting 0.5-2% of the population. The exact etiology of the condition is unknown, but the result is autoimmune destruction of melanocytes. The eye is rich in melanocytes, especially in the retinal pigment epithelium and choroid. Little is known about the effect of vitiligo on the choroid of the eye.
We cross-sectionally examined 31 right eyes of 31 vitiligo patients and 32 right eyes of 32 age- and sex-matched controls for signs of vitiligo affection and then measured the subfoveal choroidal thickness (SFCT) using spectral-domain optical coherence tomography.
There was a statistically significant difference between SFCT in the cases group and the control group (Mean ± SD 251.9 ± 42.0 μm and 296.8 ± 46.4 μm, respectively, p = 0.0002). The thickness correlated negatively with age (r = -0.5) but did not correlate significantlywith disease severity or duration (r = -0.201, -0.1781, p = 0.2783, 0.3381, respectively). Additional examination findings included iris and fundus hypopigmented spots, and peripapillary atrophy.
SFCT is reduced among patients with vitiligo. The clinical implications of such a finding should be studied further, and eye screening programs should be considered.
SFCT is reduced among patients with vitiligo. The clinical implications of such a finding should be studied further, and eye screening programs should be considered.The diagnosis and management of glaucoma has long been dependent on making decisions based on family history, optic nerve head evaluation, intraocular pressure, visual field testing, and optical coherence testing. Other pieces to aid in understanding glaucoma have presented throughout the years, including the role of corneal thickness. The discussion and debate on the mechanism of glaucoma have been attributed to resistance at the level of the conventional outflow pathway, perfusion pressure to the optic nerve head, cerebral spinal fluid pressure, and many more. Another piece that has emerged is corneal hysteresis, an assessment of the cornea's ability to absorb and dissipate energy. There is abundant published literature supporting corneal hysteresis being associated with the presence and severity of glaucoma, the structural and functional progression of glaucoma, and the conversion to glaucoma. The supported data in these studies add another piece, corneal hysteresis, to consider in the diagnosis and management of glaucoma.
This article aims to review the current and upcoming treatment options of primary muscle channelopathies including the non-dystrophic myotonias and periodic paralyses.
The efficacy of mexiletine in the treatment of myotonia is now supported by two randomised placebo-controlled trials, one of which utilised a novel aggregated n-of-1 design. This has resulted in licencing of the drug via orphan drug status. There is also good evidence that mexiletine is well tolerated and safe in this patient group without the need for intensive monitoring. A range of alternative antimyotonic treatment options include lamotrigine, carbamazepine and ranolazine exist with variable evidence base. In vitro studies have shown insight into reasons for treatment failure of some medications with certain genotypes opening the era of mutation-specific therapy such as use of flecainide. In the periodic paralyses, the ability of MRI to distinguish between reversible oedema and irreversible fatty replacement makes it an increasingly useetine shows that innovative trial design can overcome these hurdles. Further research is required to test efficacy of drugs shown to have promising characteristics in preclinical experiments such as safinamide, riluzule and magnesium for myotonia or bumetanide for hypokalaemic periodic paralysis.Filamentary enstatite crystals are found in interplanetary dust particles (IDPs) of likely cometary origin but are very rare or absent in meteorites. Crystallographic characteristics of filamentary enstatites indicate that they condensed directly from vapor. We measured the O isotopic composition of an enstatite ribbon from a giant cluster IDP to be δ18O = 25 ± 55, δ17O = -19 ± 129, Δ17O = -32 ± 134 (2σ errors), which is inconsistent at the 2σ level with the composition of the Sun inferred from the Genesis solar wind measurements. The particle's O isotopic composition, consistent with the terrestrial composition, implies that it condensed from a gas of nonsolar O isotopic composition, possibly as a result of vaporization of disk region enriched in 16O-depleted solids. The relative scarcity of filamentary enstatite in asteroids compared to comets implies either that this crystal condensed from dust vaporized in situ in the outer solar system where comets formed or it condensed in the inner solar system and was subsequently transported outward to the comet-forming region.
