الفهرس 
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Abstract
Macular edema is a common sight-threatening complication in patients with diabetic retinopathy, especially those with insulin-dependent DM, longer duration of diabetes and high levels of glycosylated haemoglobin.
Breakdown of retinal-blood barrier has been proven to be a key factor in pathogenesis of macular edema, resulting in extravasation of proteins and other substances into extracellular space followed by accumulation of fluid within extracellular space and development of macular edema.
Over years, color fundus photography was the gold standard for diagnosis of diabetic macular edema. In addition, fluorescein angiography was usually performed to identify the treatable leaking lesions and to evaluate ischemic areas.
In the current era of anti-VEGFs, OCT become a mandatory tool for diagnosis and treatment protocols of DME patients. Rather than thickness measurements, OCT can demonstrate structural changes involving different retinal layers such as formation of cystic spaces, accumulation of subretinal fluid, vitreomacular interface abnormalities and structural integrity of outer retinal layers.
In this retrospective study, we aimed to correlate the OCT findings at presentation with visual acuity outcome after treatment in patients with Ci-DME.
The study included 171 eyes of 116 patients with treatment-naïve Ci-DME, defined as diabetic macular edema involving foveal zone “central 1-mm area on ETDRS grid circle” with CST of at least 300 m (~2 SD beyond average thickness on SpectralisSD-OCT), of either cystic or spongiform pattern with or without subretinal fluid collection, and a follow-up period of at least six months. Patients with other conditions that may affect visual acuity such as AMD, glaucoma or macular dystrophy were excluded.
Clinical data from files of patients fulfilling inclusion criteria were reviewed; including age, sex, diabetic retinopathy status and visual acuity measured at presentation and during treatment period at 3, 6 and 12 months. Their SD-OCT scans were also evaluated regrading certain parameters, including CST, macular volume, pattern of edema, SFCT, vitreomacular interface abnormalities, and structural integrity of both inner and outer retinal layers.
Collected data were subjected to statistical analysis and the following results were obtained:
1. A statistically significant improvement in BCVA were found at all follow up visits compared to baseline.
2. A statistically significant decrease in CST and macular volume of edema were found at all follow up visits.
3. Low BCVA at presentation was significantly correlated :
• Higher edema volume
• Thicker CST
• Presence of SRF collection
• Presence of intra-retinal hyper-reflective foci
• ELM distortion
4. Low BCVA at 12th month follow up visit was significantly correlated to baseline:
• EZ distortion
• ELM distortion
• Presence of DRIL
5. Better VA outcome at 12th month follow up visit was significantly correlated to 3rd month volume of edema and EZ-ELM structural integrity. Patients with less edema volume and intact both EZ and ELM lines showed better final VA
6. Of all SD-OCT parameters studied, only SFCT, ELM integrity and DRIL status were found significantly related to change in VA over the study period. Patients presenting with thicker SFCT, intact ELM and no DRIL are likely to have better visual acuity at 12th month follow up visit.
7. Change in CST over study period was statistically correlated to baseline:
• CST
• ELM integrity
• Presence of DRIL
With patients presenting with higher CST, intact ELM and no DRIL are likely to show better anatomical improvement at 12th month follow up visit.
Our results were in close agreement with similar studies worldwide that looked for different factors that may affect either anatomic or functional outcomes in DME-treated patients. Limitations of our work are inherent to its retrospective nature as it is possible that some of the studied parameters were not sufficiently powered to detect its subtle association with VA.