archives@tulane.edu / Although human smell functions, in part, to detect disease and mate quality and is the sensory modality most strongly tied to disgust, its role in social cognition and behavior remains largely understudied. The current study investigated the relationship between olfactory acuity, disgust sensitivity, and prejudice toward outgroups heuristically linked to disease (i.e., overweight, gay male, older targets) using the Sniffin’ Sticks extended test among a non-clinical sample (N = 170). Based on pilot data, higher acuity was predicted to be associated with higher sexual disgust sensitivity. Both higher acuity and sexual disgust sensitivity were also predicted to be related to greater outgroup prejudice. Results found smell acuity to be positively, though not significantly related to sexual disgust. Contrary to original predictions, smell was negatively (though non-significantly) associated with outgroup prejudice for all measures except for ageism—higher acuity significantly correlated with less ageist beliefs. Furthermore, sexual disgust was not significantly related to any explicit prejudice measures, but exploratory analyses revealed a potential relationship with some less explicit measures. Current study limitations and future considerations for research investigating the role of smell and disgust in intergroup prejudice are discussed. / 1 / Zachary Airington

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A dissertation submitted to the Faculty of Health Sciences, University of the Witwatersrand, in the fulfillment of the requirements for the degree of Master of Medicine in Ophthalmology. Johannesburg, February 2017 / Purpose: To evaluate if corneal collagen crosslinking carried out on patients with keratoconus, slows down or halts the progression of keratoconus. To determine which group of keratoconus patients benefited most from the procedure. Methods: A retrospective record review of 41 eyes of 29 patients. Visual acuity and keratometry measurements were recorded for the involved eye pre-crosslinking and at 3 months and 6 months post-crosslinking. A comparison of these variables pre-crosslinking and at 6 months post-crosslinking was made to determine if there was a flattening of corneal curvature (keratometry readings) and an improvement in visual acuity. Patients were further divided into 3 groups of keratoconus, based on their keratometry readings (measured in diopters): mild keratoconus (≤47 diopters), moderate keratoconus (48 – 54 diopters) and advanced keratoconus (≥55 diopters), to determine which group of keratoconus had the best keratometry reduction readings. Results: After crosslinking took place on 41 eyes, the UnVA of 16(39%) eyes showed an improvement at 6 months, 17(41%) eyes showed no change and 8(20%) eyes showed a decrease in UnVA at 6 months, compared to pre-CXL values. For BCVA, 12(29%) eyes showed an improvement at 6 months, 18(44%) eyes showed no change and 11(27%) eyes showed a decrease in BCVA at 6 months, compared to pre-CXL values. Keratometry readings however showed that 23(56%) eyes had an average flattening of corneal curvature readings of 0.7 D and the remaining 18(44%) eyes showed more steepening (worsening) of the corneal curvature readings of 0.9 D after 6 months post-CXL. 30(73%) eyes had mild keratoconus, 7(17%) had moderate keratoconus and 4(10%) had advanced keratoconus. 19 of the 30 eyes in the mild keratoconus group (73%) showed an average flattening of corneal curvature of 0.6 D. 4 of the 7 eyes in the moderate keratoconus group (17%) showed an average flattening of corneal curvature of 0.7 D. All 4 patients in the advanced group (10%) had steepening (worsening) of their corneal curvatures with an average of 1.2 D. Conclusion: Corneal collagen crosslinking performed on keratoconus patients at least halts the progress of keratoconus. 6 months after CXL most patients showed minimal change from pre-CXL to 6 months in both visual acuity and keratometry. However a longer follow up period and larger sample size is needed to determine if vision and keratometry readings can improve significantly. / MT2017

The main purpose of this thesis is to create and validate a visual acuity model with experimentally obtained aberrations of human eyes. The other motivation is to come up with a methodology to objectively predict the potential benefits of photorefractive procedures such as customized corrections and presbyopic LASIK treatments. A computational model of visual performance was implemented in MATLAB based on a template matching technique. Normalized correlation was used as a pattern matching algorithm. This simulation describes an ideal observer limited by optics, neural filtering, and neural noise. Experimental data in this analysis were the eye’s visual acuity (VA) and 15 modes of Zernike aberration coefficients obtained from 3 to 6 year old children (N=20; mean age= 4.2; best corrected VA= 0 (in log MAR units)) using the Welch Allyn Suresight instrument. The model inputs were Sloan Letters and the output was VA. The images of Sloan letters were created at LogMAR values from -0.6 to 0.7 in steps of 0.05. Ten different alphabet images, each in ten sizes, were examined in this model. For each simulated observer the results at six noise levels (white Gaussian noise) and three levels of threshold (probability of the correct answer for the visual acuity) were analyzed to estimate the minimum RMS error between the visual acuity of model results and experimental result.

The main purpose of this thesis is to create and validate a visual acuity model with experimentally obtained aberrations of human eyes. The other motivation is to come up with a methodology to objectively predict the potential benefits of photorefractive procedures such as customized corrections and presbyopic LASIK treatments. A computational model of visual performance was implemented in MATLAB based on a template matching technique. Normalized correlation was used as a pattern matching algorithm. This simulation describes an ideal observer limited by optics, neural filtering, and neural noise. Experimental data in this analysis were the eye’s visual acuity (VA) and 15 modes of Zernike aberration coefficients obtained from 3 to 6 year old children (N=20; mean age= 4.2; best corrected VA= 0 (in log MAR units)) using the Welch Allyn Suresight instrument. The model inputs were Sloan Letters and the output was VA. The images of Sloan letters were created at LogMAR values from -0.6 to 0.7 in steps of 0.05. Ten different alphabet images, each in ten sizes, were examined in this model. For each simulated observer the results at six noise levels (white Gaussian noise) and three levels of threshold (probability of the correct answer for the visual acuity) were analyzed to estimate the minimum RMS error between the visual acuity of model results and experimental result.

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Thesis (M.S.)--Virginia Polytechnic Institute and State University, 1992. / Vita. Abstract. Includes bibliographical references (leaves 46-51). Also available via the Internet.

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