الفهرس 
IntroductionOnly 14 pages are availabe for public view
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Abstract
This current study consisted of 40 normal control group, 50 DM without DR patients without diabetic retinopathy, 100 type1 DM <40 patients subdivided into non-proliferative DR < 40 years with and proliferative DR <40 years and 100 type 2DM >40 patients subdivided into non-proliferative DR >40 years and proliferative DR <40 years. In our study, there is longer duration of type1 DM with DR <40 specially type 1DM with proliferative DR (16.5±4.48) than type 2 DM >40 with proliferative DR (13.6±5.60). The best corrected visual acuity (BCVA) decrease in diabetic retinopathy either type1 DM < 40 years or type2 DM ≥ 40 years groups with the decrease in vascular density. The present study used vascular density (VD) and FAZ area as indicator for the retinal and ciliary blood flow of macula and optic disc in diabetic eyes compared their quantitative indices with those of their normal controls. Comparing quantitative OCTA findings of DR with normal eyes may be useful in staging DR severity. In our study, The quantitative OCTA assessment of the macular vascular density in diabetic eyes without DR, in type 1 DM without DR< 40 years showed decreased superficial and deep capillary plexuses VD in comparison to normal control group < 40, in type 2 DM without DR ≥ 40 years showed decreased VD in deep but not in superficial capillary plexus in comparison to normal control group ≥ 40 years. Macular vascular density showed significant decreased superficial and deep capillary plexuses VD in DR type 1 DM<40 years either proliferative and non-proliferative in comparison to normal control group <40 years, while in DR type 2DM ≥ 40 years there was decrease in superficial capillary plexus VD and decrease in deep capillary plexus VD compared to their normal control group. Also there is decrease in SCP and DCP VD in type 2 DM ≥ 40 years non-proliferative and proliferative in comparison to SCP and DCP VD of DM type1 <40 years. Choriocapillaris (CC) alterations are believed to contribute to the pathogenesis of DR. OCTA can visualize blood vessels as deep as the choriocapillaris (CC) and choroid that are not seen on clinical examination or FA. Better understanding of choroidal changes may help to predict disease progression. In our study choriocapillaris vascular density (CCVD) was decreased in DM type 1 without retinopathy <40 years and decreased in DM type 2 without retinopathy ≥40 years compared to their normal control groups. choriocapillaris vascular density (CCVD) is significantly decreased in DM type 1 DR <40 years either proliferative or non-proliferative and significantly decreased in DM type2 DR ≥40 years either proliferative or non-proliferative compared to their normal control groups. And there is significant decrease in CCVD in proliferative DR in comparison to non-proliferative DR in type 1 and type 2 DM. In our study, The FAZ area is objective measurement that showed a small but significant enlargement of the FAZ area in diabetic eyes in comparison to their normal control groups. Disorganization of the retinal inner layers (DRIL) as an OCT biomarker was associated with enlarged FAZ area in both SCP and DCP. Patients with interrupted outer retinal layer (both ELM and photoreceptors) associated with decreased choriocapillaris VD in DR. Few studies have used OCTA to determine changes in ONH microcirculation in DR. our study reported significant decrease in superficial, deep papillary plexuses and CCVD in diabetics compared to their normal controls and in type 2 DM compared to type 1 DM. Also, OCTA is clinically useful in evaluating NVD shape size and the therapeutic effect of treatments for NVD in PDR. In our study there is a negative correlation between duration of diabetes and the vascular density of macula and disc. And choroidal thickness decreased with the progress of stage of DR. choroidal vascular density is affected by duration of diabetes (negative correlation), decreased CC vascular density in the macula may be an early indicator of diabetic vasculopathy. Further studies with long period follow up are needed to confirm these microvascular changes over time in diabetic eyes. There is a positive correlation between macular thickness (central sub-field thickness) and FAZ area which was affected more in deep capillary plexus.