Changes in Posterior Segment Optical Coherence Tomography after Intravitreal Triamcinolone Acetonide Infection

Introduction: Triamcinolone acetonide is a potent synthetic corticosteroid. It is a long acting depot preparation of triamcinolone having solely glucocorticoid activity. As a part of glucocorticoid activity, it also possesses a profound anti-inflammatory property that forms the basis of its therapeutic uses in various inflammatory and oedematous diseases of posterior segment of eyes. Optical Coherence Tomography (OCT) is a very useful tool to monitor the therapeutic response of various posterior segment pathologies after Intravitreal Triamcinolone Acetonide (IVTA) injection. Aim: To study the effect of IVTA injection on central foveal thickness in various diseases of posterior segment and to see the impact of OCT changes on visual acuity. Materials and Methods: This prospective interventional study was conducted on 30 patients (30 eyes) out of which 17 were males and 13 were females, with age ranging from 15 to 75 years, Control group consisted of 30 patients (untreated healthy other eye of the patients enrolled in the study). The study group comprised of cases of posterior uveitis (n=12), retinal vascular occlusive diseases (n=10), Eales' disease (n=6), pseudophakic cystoid macular oedema (n=1) and idiopathic cystoid macular oedema (n=1). All patients in the study group received single intravitreal injection of 4 mg triamcinolone acetonide. A thorough ophthalmic examination (including LogMAR visual acuity, applanation tonometry, slit lamp biomicroscopy and fundus examination) was also done at baseline and two weekly follow-up after IVTA injection up to 12 weeks follow-up. Posterior segment OCT and Fundus Flourescein Angiography (FFA) were done at baseline and in the follow-up at 6 weeks and at 12 weeks to study the response to treatment. Macular thickness was documented in a modified Early Treatment of Diabetic Retinopathy Study (ETDRS) macular map. The retinal thickness in each of quadrants (of parafoveal and perifoveal subfields) and Central Foveal Thickness (CFT) were measured at baseline and at 6 and 12 weeks followup. Continuous variables were expressed as mean, Standard Deviation (SD) and range. Paired t-test was used to assess the statistical significance of differences in various variables at baseline and in the follow-up within the group. Pearson's correlation coefficient was used to find out correlation between CFT and LogMAR visual acuity and between change in CFT and change in LogMAR visual acuity on follow-ups in study group. Results: The mean LogMAR visual acuity was 0.67 +/- 0.55 at baseline. After IVTA injection it improved to 0.37 +/- 0.33 at 6 weeks (p<0.001) and 0.30 +/- 0.29 at 12 weeks (p<0.001) compared with the baseline. The mean baseline CFT in study group was 350.73 +/- 149.14 mu M. After IVTA it decreased to 228.47 +/- 67.85 mu M (p<0.001) and 250.27 +/- 82.09 mu M (p<0.001) at 6 weeks and 12 weeks follow-up respectively. The mean baseline Intraocular Pressure (IOP) in study group was 14.27 +/- 3.53 mmHg. After 4 mg of IVTA injection mean KW was 16.54 +/- 4.29, 18.54 +/- 5.50, 19.00 +/- 5.98, 18.82 +/- 5.00 and 22.50 +/- 0.71 mmHg at 2, 4, 6, 8 and 12 weeks follow-up respectively. IOP elevation of >= 6 mmHg from baseline was seen in 17 out of 30 eyes. The majority of patients belonged to younger age group. In 15 out of 17 eyes, IOP was controlled with topical anti-glaucoma medications while 2 eyes required filtering glaucoma surgery. Conclusion: There was significant decrease in macular thickness after intravitreal triamcinolone acetonide injection in all cases of inflammatory diseases of posterior segment like posterior uveitis and Eales' disease but recurrence in macular oedema was seen in pseudophakic eyes at 12 weeks followup. Significant improvement of Visual Acuity (VA) was seen and change in macular thickness was associated with change in visual acuity in all cases after IVTA.