The role of macular hydration in the evaluation of the effect of intravitreal triamcinolone on visual acuity in eyes with diabetic macular edema.

To evaluate the efficacy of intravitreal triamcinolone (IVTA) in eyes with clinically definite diabetic macular edema (DME) by using the parameters visual acuity (VA), central macular thickness (CMT) and macular hydration (MH). Medical records of patients who received IVTA (4 mg/0.1 mL) for DME were reviewed. Optically non-reflective areas which appear dark spaces within the 1000 μm from the center of the macula on OCT scan defined as MH. Best corrected logarithm of minimum angle of resolution (logMAR) visual acuity, CMT as determined by optical coherence tomography (OCT) and MH quantified from the OCT scans by using metamorph analysis were evaluated before the injection and at 1, 3 and 6 months in all, and up to 12 months in some eyes, after the IVTA injection. The correlations between these variables were also studied. 28 eyes of 27 patients were included in the study. Eyes with DME treated by a single IVTA injection responded with a trend towards significant improvement in logMAR VA at 1 (p < 0.0001) and 3 months (p < 0.0001), but no significant improvement in relation to baseline at 6 months was observed (p = 0.07). CMT was significantly reduced at 1 month (p < 0.0001), 3 months (p < 0.0001) and 6 months (p = 0.01) compared to baseline. Like the trend observed in VA improvement, MH also significantly reduced at 1 month (p < 0.0001) and 3 months (p < 0.0001), but not at 6 months (p = 0.14) compared to baseline. There was no correlation between the VA ratio and the CMT ratio (r = 0.18, p = 0.36), but there was a significant correlation between the VA ratio and the MH ratio (r = 0.85, p < 0.0001). There was also an inverse relationship between MH ratio and the age of the patients (r = -0.7089, p = 0.0001). Macular hydration seems to be a better parameter than macular thickness for determining the effectiveness of IVTA treatment in a subset of eyes with DME. Although the treatment effect is temporary, younger patients with DME were more prone to respond with a greater reduction in MH after IVTA injection.