97 research outputs found

    Systemic risk factors of dry eye disease subtypes:A New Zealand cross-sectional study

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    PURPOSE: To evaluate systemic risk factors of dry eye disease, aqueous tear deficiency, and meibomian gland dysfunction. METHODS: Three hundred and seventy-two community residents (222 females, 150 males; mean ± SD age, 39 ± 22 years) were recruited in a cross-sectional study. Past medical history, dry eye symptomology, ocular surface characteristics, and tear film quality were evaluated for each participant within a single clinical session. The diagnosis of dry eye disease, aqueous tear deficiency, and meibomian gland dysfunction were based on the global consensus recommendations of the Tear Film and Ocular Surface Society's Dry Eye Workshop II (TFOS DEWS II) and International Workshop on Meibomian Gland Dysfunction. RESULTS: Overall, 109 (29%) participants fulfilled the TFOS DEWS II criteria for dry eye disease, 42 (11%) had aqueous tear deficiency, and 95 (26%) had meibomian gland dysfunction. Multivariate logistic regression analysis demonstrated that systemic rheumatologic disease and antidepressant medication were independently associated with aqueous tear deficiency (both p < 0.05). Significant risk factors for meibomian gland dysfunction included age, East Asian ethnicity, migraine headaches, thyroid disease, and oral contraceptive therapy (all p ≤ 0.01). CONCLUSIONS: Both etiological subtypes of dry eye disease were associated with a number of systemic risk factors. These findings would support routine systemic inquiry of dry eye disease and associated systemic conditions and medications, in order to facilitate opportunistic screening and timely inter-disciplinary referral where necessary

    Electron Transmission Spectroscopy in Atomic Hydrogen

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    An electron transmission experiment is used to study the resonances in the total scattering cross section of atomic hydrogen below the threshold of the first excited state. The three lowest resonances, designated 1S, 3P, and 1D, are observed and their energies and decay widths are found to be in good agreement with the values predicted theoretically using close coupling with correlation

    Electron excitation of alkali atoms. [EACLOC computer code for excitation of alkali atoms by electron collisions]

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    The development and testing of a synthesized close-coupling effective model potential ten-channel electron-atom scattering code and some preliminary calculations of resonances in cross sections for the excitation of excited states of potassium by low energy electrons are described. The main results obtained are: identification of /sup 1/S and /sup 1/D structures in excitation cross sections below the 5/sup 2/S threshold of neutral potassium; indications of additional structures - /sup 1/P and /sup 1/D between the 5/sup 2/S and 5/sup 2/D thresholds; and a suggested explanation of anomalously high interstate-electron impact excitation cross sections inferred from experiments on potassium-seeded plasmas. The effective potential model imbedded in the code can be used to simulate any atomic system that can be approximated by a single bound electron outside an ionic core. All that is needed is a set of effective potential parameters--experimental or theoretical. With minor modifications the code could be adapted to calculations of electron scattering by two-electron systems

    Negative ions in electron impact excitation of He near 60 eV

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    An experimentally verifiable effect on the excitation cross section in helium due to the broad (2s2p2) 2Se He- state predicted by Fano and Cooper in 1965, but hitherto unidentified, and other He- states, are predicte

    Post-operative changes in the capsulorhexis aperture: a prospective, randomised comparison between loop and plate haptic silicone intraocular lenses.

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    PURPOSE: There is disagreement regarding whether the capsulorhexis aperture always decreases or may increase post-operatively. The aim of this study was to settle the controversy concerning loop haptic silicone lenses and to learn more of the dynamics of the capsulorhexis relating to plate haptic lenses. METHODS: We performed a prospective randomised study comparing the post-operative changes in capsulorhexis aperture in two groups of eyes implanted with either plate or loop haptic silicone intraocular lenses. All the surgery was performed, at a teaching hospital in the United Kingdom, by a single surgeon, using a standard technique of phacoemulsification. Patients were reviewed at 2 weeks and 6 months post-operatively. Digital retroillumination images of the anterior segment were captured. The area of the capsulorhexis aperture was determined by manually detecting its edge on a computer monitor. RESULTS: Forty-eight cases were randomised. The groups were comparable for demographic variables and mean initial aperture size (p &gt; 0.05). There was an 8.4% mean decrease in aperture size for the loop haptics, contrasting with 4.5% expansion for the plate haptics (p &lt; 0.05). Sixty-five per cent of patients with the plate haptic underwent enlargement of the aperture, contrasting with 25% for the loop haptic lens (p &lt; 0.05). CONCLUSIONS: Silicone lenses with plate haptics undergo expansion of the capsulorhexis aperture more frequently than those with Prolene loop haptics
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