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ndltd-OhioLink-oai-etd.ohiolink.edu-osu1314731272
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ndltd-OhioLink-oai-etd.ohiolink.edu-osu13147312722021-08-03T06:03:47Z Chemo-mechanical modification of the corneal response to photokeratectomy Dupps, William J., Jr. <p>Unintended anterior corneal flattening is a poorly understood complication of excimer laser phototherapeutic keratectomy (PTK) that pervades clinical practice despite efforts to remove a geometrically neutral lenticule of tissue during ablation. This document describes investigations into a model of keratectomy-induced curvature change in which intraoperative thickening of the stroma peripheral to the ablation zone is implicated as a mechanical stimulus for flattening of the central cornea. A paired-control human donor eye study was conducted to assess the efficacy of preoperative topical glutaraldehyde (GTA) treatment as a technique for inhibiting PTK-induced peripheral stromal thickening and, secondarily, for attenuating the acute corneal flattening response.</p><p>Twenty whole globes acquired in same-donor pairs were individually mounted in a custom holder, inflated to normal intraocular pressure (15 mmHg) and deepithelialized. According to a crosslinking protocol developed in preliminary experiments, one cornea of a given donor pair was immersed in a 15% dextran solution for 40 minutes then transferred to 4% GTA/dextran for an additional 20 minutes; the fellow control was exposed to 15% dextran for 60 minutes. Each eye was subsequently subjected to 1) sham PTK, a same-eye control phase incorporated to account for thinning due to intraoperative dehydration, 2) PTK (5-mm-diameter, 100-um-depth) and 3) a 1-hour hypo-osmotic soak phase designed to assess the anti-swelling activity of stromal crosslinking. A scanning-slit topography system was used to acquire triplicate thickness and curvature measurements before and after each experimental phase.</p><p>Crosslinking significantly inhibited peripheral stromal thickening during PTK and postoperative hypo-osmotic immersion. In addition, during PTK, crosslinked corneas demonstrated 36% less hyperopic shift relative to paired controls (p = .001). The magnitude of this latter effect was linearly dependent upon the magnitude of crosslink-mediated suppression of the peripheral thickening response to PTK (r = 0.68, p =.03). The results demonstrate that acute hyperopic shifts in a donor model of PTK can be significantly reduced through preoperative application of a collagen crosslinking reagent and therefore support the conclusion that mechanical events in the corneal periphery play an important role in keratectomy-induced central curvature changes. This mechanism of curvature change is not accounted for in current surgical algorithms.</p> 1998 English text The Ohio State University / OhioLINK http://rave.ohiolink.edu/etdc/view?acc_num=osu1314731272 http://rave.ohiolink.edu/etdc/view?acc_num=osu1314731272 unrestricted This thesis or dissertation is protected by copyright: all rights reserved. It may not be copied or redistributed beyond the terms of applicable copyright laws.
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NDLTD
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| language |
English
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| sources |
NDLTD
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| author |
Dupps, William J., Jr.
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| spellingShingle |
Dupps, William J., Jr.
Chemo-mechanical modification of the corneal response to photokeratectomy
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| author_facet |
Dupps, William J., Jr.
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| author_sort |
Dupps, William J., Jr.
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| title |
Chemo-mechanical modification of the corneal response to photokeratectomy
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| title_short |
Chemo-mechanical modification of the corneal response to photokeratectomy
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| title_full |
Chemo-mechanical modification of the corneal response to photokeratectomy
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| title_fullStr |
Chemo-mechanical modification of the corneal response to photokeratectomy
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| title_full_unstemmed |
Chemo-mechanical modification of the corneal response to photokeratectomy
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| title_sort |
chemo-mechanical modification of the corneal response to photokeratectomy
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| publisher |
The Ohio State University / OhioLINK
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| publishDate |
1998
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| url |
http://rave.ohiolink.edu/etdc/view?acc_num=osu1314731272
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| work_keys_str_mv |
AT duppswilliamjjr chemomechanicalmodificationofthecornealresponsetophotokeratectomy
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| _version_ |
1719430227276333056
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