الفهرس 
IntroductionOnly 14 pages are availabe for public view
 |  | from | 51 |  |  |
| | | from | 51 | | |
Abstract
The global incidence of diabetes mellitus (DM) is increasing, and the number of
patients is expected to reach 3.66 billion by 2030. Diabetic retinopathy (DR) is one of
the most common and severe complications of DM and is also the leading cause of
blindness [59].
The choroid receives 95% of all ocular blood flow and provides oxygen and
nutrients to the outer third of the retina, thus making it a tempting target for vascularrelated
studies in diabetic patients. In fact, studies focused on the role of the choroidal
layer in the pathogenesis of DR and identified an entity diabetic choroidopathy. The
vascular choroid changes of the diabetic patients are quite similar to those seen in DR,
such as increased vascular tortuosity, vascular outpouchings, microaneurysms,
nonperfusion areas, vascular dilations and narrowing, and choroidal neovascularization
[60].
With the advent of optical coherence tomography (OCT) technology, detailed
visualization of the choroid in vivo is now possible. Measurements of choroidal
thickness have also enabled new directions in research to study normal and pathological
processes within the choroid. Enhanced depth imaging (EDI) OCT, has been shown to
be able to reliably image the full-thickness of the choroid. EDI OCT uses SD-OCT
equipment positioned closer to the eye than ordinary, such that a stable inverted image
is produced. The net effect of this practice is that the sensitivity of the imaging in deeper
layers of tissue is increased. In this fashion, EDI OCT may represent a useful approach
to investigate, in vivo, the choroidal changes [61].
Increases and decreases in macular and choroid thicknesses have been observed
in patients with and without diabetic retinopathy in previous studies, and different
mechanisms have been found to be responsible for these changes [62].
Our study aimed to Compare between Enhanced Depth Imaging Optical
Coherence Tomography in normal persons and diabetic patients with no clinical
diabetic retinopathy.
This is cross-sectional, case–control study included 60 participants, The patients
were recruited from the Ophthalmology Department, Menoufia University Hospitals
from January 2019 to January 2020 after approval from the Research and Ethics
Committee of Faculty of Medicine, Menoufia University.
Patients and controls were classified into the following groups:
1. group I: consisted of 30 patients diagnosed to have type 1 or type 2 diabetes mellitus
by an endocrine specialist.
2. group II: consisted of 30 normal control subjects were selected from the medical
examination center of the same hospital. They were age- and sex-matched to the
patients; free of all diagnoses of ocular disease, diabetes, or other systemic disease;
and were subjected for a complete ophthalmologic examination.
All participants included in the study signed an informed written consent. Data
were collected in a preorganized data sheet (Case Sheet) by the researcher from patients
fulfilling the inclusion and exclusion criteria.
Summary
34
Diagnosis of T1DM or T2DM with no clinical retinopathy as observed through
dilated pupils by an experienced doctor using a stereoscopic slit lamp with a handheld
lens. ,Best-corrected visual acuity ≥20/25. And refractive errors below -6 or above +3
diopter equivalent spheres.
Significant media opacity, Glaucoma, Uveitis Ocular trauma or surgery history
and serious systemic diseases.
All participants were subjected to thorough history taking, clinical general and
local examination, and investigations in the form of Optical Coherence Tomography:
group I showed 28 (93.3%) was on oral treatment and 2 (6.7%) was on Insulin.
Regarding to other disease: group I showed 20 (66.7%) had no other disease and 10
(33.3%) was HTN. group II showed 30 (100.0 %) had no other disease and no one has
HTN. The difference was statistically significant regarding other diseases. Regarding to
fundus examination: both groups were normal. Regarding to Choroidal thickness:
group I showed a less Choroidal thickness than group II. mean Choroidal thickness for
group I was 222.9 ± 24.75 and group II was 291.3 ± 40.58. (P value> 0.001).
We showed that in diabetic eyes, there is an overall thinning of the choroid on
EDI OCT. These data favor the idea that, in diabetic eyes, decreased choroidal thickness
may lead to tissue hypoxia. Thickness with cut off ≤ 253 had a high ability to predict
diabetic patients with no clinical diabetic retinopathy with sensitivity 96.67 % and
specificity 80.0%.