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العنوان
Enhanced Depth Imaging Optical Coherence Tomography: A Study of the Choroid in High Axial Myopia /
المؤلف
Zayed, Samar Osama Ahmed El Gharib.
هيئة الاعداد
باحث / Samar Osama Ahmed El Gharib Zayed
مشرف / Sherif Zaki Mansour
مشرف / Ayman Abd El Moneim Gaafar
مناقش / Abdel Rahman Gaber Salman
تاريخ النشر
2018.
عدد الصفحات
142 P. :
اللغة
الإنجليزية
الدرجة
الدكتوراه
التخصص
طب العيون
تاريخ الإجازة
1/1/2018
مكان الإجازة
جامعة عين شمس - كلية الطب - قسم طب وجراحة العيون
الفهرس
Only 14 pages are availabe for public view

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from 156

Abstract

Summary
H
igh myopia is one of the main causes of visual impairment worldwide. About 1% of the population has high myopia. There is significant evidence from research, that the development of refractive errors is associated with changes in the structural characteristics of the choroid.
It is essential to understand how choroidal thickness in xdifferent regions of the macula vary with refractive error, axial length, to fully appreciate the effects of the disease process on the choroid.
The purpose of this study is to evaluate the choroid by enhanced depth imaging optical coherence tomography, as regards its morphology and thickness in high axial myopic patients and compared with healthy subjects. The study included 101 high axial myopic eyes (more than -6.00 diopters; group I). This group was subdivided according to the level of myopia into: group Ia: from -6 diopters till -10 diopters, group Ib: from more than -10 diopters till -15 diopters, group Ic: from more than -15 diopters till -20 diopters and group Id: from above -20 diopters. It also included 101 emmetropes as controls (group II).
All subjects underwent full ophthalmologic examination in addition to axial length measurement and enhanced depth imaging optical coherence tomography of the choroid. The choroidal thickness was measured at 5 locations, including subfoveal choroidal thickness, 3-mm nasal, 3-mm temporal, 3-mm upper, and 3-mm lower to fovea.
In this study we found that the choroidal thickness was statistically significantly lower in myopic eyes191.0±69.4 (p<0.001), compared to controls 348.0±59.0 (p<0.001).
In this study, the thickest measures were found in the upper region in the advanced myopic eyes in which the CT was 258.0±49.9 µm in group Ia, 219.4±54.52 µm in group Ib, 167.9±37.5 µm in group Ic and 157.5±22.9 µm in group Id.
Whereas, the thinnest region was found in the nasal region in which the CT was 185.0±46.9 µm in group Ia, 136.3±55.9 µm in group Ib, 97.8±29.9 µm in group Ic and 95.8±31.1 µm in group Id.
Also, we found that the axial length had a statistically significant positive correlation with refraction, but showed a statistically significant negative correlation with subfoveal choroidal thickness, choroidal thickness 3-mm nasal, choroidal thickness 3-mm temporal, choroidal thickness 3-mm upper, and choroidal thickness 3-mm lower.
The presence of posterior staphyloma, a hallmark of high myopia, was found to have a statistically significant association with choroidal thinning. Also, in this study, cases with staphyloma were found to have a statistically significant higher uncorrected visual acuity, intra ocular pressure & axial length and a statistically significant lower choroidal thickness in all study groups.
By plotting multiple regression analyses for myopic patients to show which factor in the study was the most important determinant of subfoveal choroidal thickness, and choroidal thickness in different positions, it was found that UCVA was the most important determinants for subfoveal choroidal thickness and all other locations in all study groups.