Intravitreal triamcinolone acetonide is a well-known method of treatment of diabetic macular edema, however, it has many side effects, most commonly causing cataract and glaucoma. Suprachoroidal route is an emerging route of delivery of intraocular drugs.

This is to our knowledge the first prospective study to compare the effect of triamcinolone acetonide delivered via the intravitreal versus the suprachoroidal route in the treatment of diabetic macular edema as regards safety and efficacy.

The purposes of this study were:

1. To compare between intravitreal and suprachoroidalTA injection for treatment of DME in terms of improvement in both best corrected visual acuity (BCVA) and central macular thickness (CMT), and development of complications.

2. To identify which dose of TA will be efficient using the suprachoroidal route.

   • Type of Study: A prospective interventional randomized comparative study.
   • Study setting:Ophthalmology Department, Ain Shams University.
   • Study period:2 years.
   • Study population: Patients having DME.
   • Sample size: The study will be conducted on 45 eyes. This was done using PASS program, setting alpha error at 5% and power at 80%. Results from previous study (Koc et al., 2017) showed that the mean improvement in BCVA after 6 months of intravitreal injection of TA was 4.6 ± 8.8. While it is assumed to be 12.6 and 14.6 for the low dose and high dose suprachoroidal route.
   • Ethical considerations: Explanation of the procedure will be done for all patients and an informed written consent will be taken. Ethics committee approval will be obtained from the Institutional Review Board of the Faculty of Medicine, Ain Shams University.

All patients will undergo the following at initial presentation:

• Careful history taking.
• Full ophthalmological assessment including:

Baseline BCVA. Anterior segment examination using slit lamp biomicroscopy. IOP measurement using Goldmann applanation tonometer. Posterior segment examination using binocular indirect ophthalmoscopy and indirect slit lamp biomicroscopy (+90D Volk lens) for detailed evaluation of the macula and optic nerve head.

Fundus photography using VX-20 Kowa fundus camera, Japan. Ultrasound biomicroscopy (UBM) for measurement of scleral thickness in groups (II) and (III)using VuMax, Sonomed Escalon, theUnited States of America.

Spectral domain optical coherence tomography (SD-OCT) imaging using Retinascan RS 3000 advance, Nidek co.ltd, Gamgori, Japan.

Examination protocol: Macular map and 12 radial line scans to determine central macular thickness (1mm) and macular thickness in the inner 3 and 6 mm rings divided each into four quadrants.

Duration of follow up: 6 months.

Follow up schedule:

Follow up visits will be done at 1 day, 1 week, 1 month,3 months and 6 months.During the follow up, the following will be done:

• BCVA measurement.
• Full ophthalmological examination.
• Fundus photography after six months of injection.
• CMT measurement using SD-OCT at 1,3 and 6 months post-injection. In case of resistance to treatment (worsening of BCVA or CMT, or persistence of macular edema with central thickness less than 300µm), reinjection will be considered using the same drug and/or anti-VEGF agents.

Inclusion Criteria:

• Type-II Diabetes Mellitus patients.
• Centrally involving DME with central thickness<300µm with no vitreomacular traction.
• Recently diagnosed DME or received treatment for DME in more than six months.

Exclusion Criteria:

• Pre-existingretinal disease other than diabetic retinopathy.
• Diabetic macular ischemia.
• IOP ≥ 21 mmHg and/or asymmetrical cup disc ratio or glaucoma patients.
• Prior cataract extraction of less than six months.
• Opaque media, uncooperative patients or patients with poor fixation.
• Any uncontrolled systemic disease.
• Systemic or local medicationsthat might affect the macular thickness