ACTION FEATURES OF THE IMPLANT WITH DEXAMETHASONE ON INDICATORS OF RETINAL VEIN OCCLUSIONS

Purpose. To investigate the effects of the implant with the Dexamethasone on the structural parameters of the central retina in case of retinal vein occlusions porch occlusion complicated with macular edema.Material and methods. The study involved 13 individuals (9 female and 4 male, 13 eyes) with the firstly diagnosed thrombosis of the central retinal vein (6 eyes – the group I) or its branches (7 eyes – the group II). The average patient age was 60.8±2.1 years. The disease duration averaged 2±0.5 months. The control group included seven fellow eyes of the examined patients (the exclusion criterion was the presence of cornea and lens opacity, diseases of retina and optic nerve, except angiopathy). All patients of study groups underwent a single performed intravitreal input of the implant with dexamethason (0.7 mg) according to a standard technique, as well as a standard course of conservative treatment. The follow-up period was 1 month.Results. In the control group the visual acuity equaled 0.94±0.06, the total photosensitivity – 19.7±0.3 dB, the mean central foveal thickness was 224.5±5.38 μm, the total macular thickness – 299.41±3.73 μm, including external layers – 165.89±2.87 μm, and internal layers – 132.77±2.26 μm (in the ratio of 0.55/0.45). A month after the treatment patients reported an improvement in the best corrected visual acuity (BCVA) from 0.04±0.02 to 0.16±0.08 in the group I (compared to the control group, p<0.05) and 0.14±0.03 to 0.5±0.16 (versus results before treatment, p<0.05) in the group II, the total photosensitivity of central retina improved at an average 1.34±1.11 to 3.63±3.03 dB (the group I) and 7.35±1.89 to 8.98±1.54 dB (the group II). According to the OCT results there was observed a significant (2.6 times) decrease in macular edema (from 856.76±101.92 to 336.46±29.45 μm, p<0.05) in the group I and 1.8 times – in the group II (from 566.46±51.51 to 324.74±21.43 μm, p<0.05). The ratio of the thickness of external retinal layers to the internal ones in the group I was 0.52/0.43, in the group II – 0.55/0.45. The macula profile in both groups acquired a regular shape with a foveola in the center, and the studied parameters were comparable to the control group. In general, a complete resorption of macular edema was detected in 10 patients (76.9%), in 1 patient with central retinal vein occlusion (7.7%) a small detachment of neuroepithelium remained unchanged, in 2 patients (15.4%) with branch retinal vein occlusion there were maintained isolated cysts in the external nuclear layer. Throughout the study period, the lenses of all patients remained clear, 1 (7.7%) patient showed an elevation in the intraocular pressure. Visometry data analyses of examined patients depending on treatment period showed a significant improvement of visual acuity comparing to results before treatment (from 0.14±0.04 to 0.58±0.14, p<0.05) in terms of intravitreal implant with dexamethasone up to 2 months.Conclusion. Intravitreal implant with dexamethasone (in 1-month follow-up period) contributes to an improvement of visual functions in patients with retinal vein occlusions including a significant increase in visual acuity in cases of branch retinal vein occlusion, partial recovery of central retina mainly due to significant changes in the thickness of external retinal layers in all types of occlusion. Intravitreal implant with dexamethasone in earlier stages (up to 2 months after occlusion) contributes to a more significant improvement of visual functions