Abstract
Abstract: :
Purpose: We have previously demonstrated that eyes that develop elevated intraocular pressure (IOP) after an intravitreal injection of triamcinolone ("IOP responders") have a strongly increased risk of developing posterior subcapsular cataract. In this study we have investigated whether there is a correlation between IOP responders, improvement of visual acuity and reduction of foveal thickness after a single intravitreal injection of 4 mg triamcinolone acetonide (IVTA) for diabetic macular oedema. Methods: In a prospective, double–masked, placebo controlled, randomised study, 33 eyes with diffuse diabetic macular oedema were treated once with an intravitreal injection of 4 mg triamcinolone acetonide. Best corrected LogMAR visual acuity, applanation tonometry and optical coherence tomography (OCT) were performed at baseline and 3 month after treatment. "Vision improvers" were defined as eyes which had improved visual acuity by 5 or more LogMAR letters at the 3 month visit compared with baseline. IOP responders were defined as eyes with an IOP increase of 5 or more mmHg at any time in the six months after the injection. The relationship between change of IOP and the reduction of foveal thickness was also evaluated. Results: 18 out of 33 (55%) IVTA–treated eyes had vision improvement by 5 or more LogMAR letters. 10 out of 33 (30%) IVTA–treated eyes had IOP elevation by 5 or more mmHg (range 5–22 mm Hg). Elevated IOP was usually, but not always, detected within 2 months after the injection. Among 10 IOP responders, there were 6 eyes (60%) with vision improvement. There was no correlation between vision improvers and IOP responders (P=0.624, r=0.07, Pearson Product Moment Correlation). The average foveal thickness was 431.3+114.5 µm before treatment compared to 278.3+83.1 µm at 3 months (p<0.001, paired t–test). There was no correlation between IOP response and thickness change at 3 month (p=0.128, r=0.238, Pearson Product Moment Correlation). Conclusions: There is no correlation between vision improvement and IOP response after IVTA injection, nor was elevated IOP associated with reduction of foveal thickness. This suggests that elevation of the IOP and vision improvement with reduction of foveal thickness occur by different mechanisms in eyes with macular oedema treated with IVTA.
Keywords: diabetic retinopathy • drug toxicity/drug effects • clinical (human) or epidemiologic studies: outcomes/complications