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Title: Clinical assessment of eye characteristics, sensitivity, and eye blink activity in humans
Author: Naase, Taher
ISNI:       0000 0001 3438 7846
Awarding Body: Glasgow Caledonian University
Current Institution: Glasgow Caledonian University
Date of Award: 2008
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The aims of this thesis were to objectively assess the characteristics of the ocular surface and tear film and possible inter-relationships with spontaneous eye blink activity. Both Arab and white European subjects (42 of each, average age 32 ±5 years) were studied, with all being generally healthy and non-contact lens wearers, All subjects completed an eye comfort questionnaire and assessments made with fluorescein of tear film stability and the tarsal surface, while lissamine green dye was used to highlight the eyelid marginal zone (Marx's line), Ocular surface sensitivity (cornea and bulbar conjunctiva) were measured with a Cochet-Bonnet aesthesiometer, the bulbar conjunctival cells sampled by impression cytology, and the spontaneous eyeblink rate (SEBR) recorded by videography. Most measures were very similar in both groups of subjects, although Arab subjects had lower tear film stability (9.7 ± 3.0 vs,14,2 ± 6.8 s, p =0,001), a wider staining with lissamine green (0.37 vs. 0.28 mm; p = 0.002), a slightly lower ocular surface sensitivity (e.g, 24.5 ± 4.4 mm vs. 28.5 ± 4.5 mm for bulbar conjunctiva, p = 0.001), but a higher eyeblink rate (18.4 ± 10.9 vs. 10.9 ± 5,9 eyeblinks/min; p =0.001). Fluorescein highlighted features (papillae) across the tarsal conjunctiva, assessed using a novel semi-automated morphometry method, had average areas from 0.028 to 0,370 mm2 (mean 0.098 ± 0,056 mm2), while the nucleus-to-cytoplasm length ratio (NUCL) of bulbar conjunctival cells ranged from 0,240 to 0.500 (mean 0.380 ± 0,060). Both sets of morphometry data correlated well with subjective grading schemes, but there was no difference between subject groups or any correlation between tarsal and bulbar surfaces (p ~ 0.2). Eyeblink rates (SEBR) ranged from 2,8 to 48.0 eyeblinks/min (mean 14.9 ± 9.9 eyeblinks/min) with analyses indicating that subjects should be considered to have either (normal or 'frequent' eyeblinking based on ~ 19 eyeblinks/min. The frequent eyeblink activity could not be statistically linked to palpebral aperture height (p ~ 0.2). Across all subjects, SEBR could be shown to be weakly correlated with conjunctival sensitivity (p = 0.014, rs = - 0.269) and the variability in the Marx line staining (p =0.019), but not to tarsal or bulbar conjunctival features (p =0.635, P = 0.913) respectively. Overall, SEBR was not dependent on film stability in either subject group (p ~ 0.4), although could be shown to be negatively correlated (p = 0.027, r = - 0.418) with tear break up time in individuals with J-type eyeblink patterns.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available