Study On Intravitreal Triamcinolone Acetonide Combined With Laser Photocoagulation For The Macular Edema Secondary To Retinal Vein Occlusion

Retinal vein occlusion (RVO) is second only to diabetic retinopathy as a cause of retinal vascular disease. Macular edema is a major cause of visual loss in patients with retinal vein occlusion. Traditional therapies for macular edema include the treatment for the initial diseases, medicine aimed in relieving macular edema and grid laser photocoagulation and so on. However, until now there is no proven effective treatment for patients with macular edema resulting from retinal vein occlusion. So, it is important to find a new and effective therapy for the macular edema secondary to retinal vein occlusion. The mechanism of visual loss in patients with macular edema due to retinal vein occlusion is not well known. Retinal veinocclusion cause macular edema by decreased tissue perfusion and increased hydrostatic pressure within the involved segments as a consequence of the vascular obstruction. Although the exact mechanism is still uncertain, it is widely accepted that macular edema results from dysfunction of the blood-retinal barrier (BRB). Persistent edema, even after recanalization, is thought to be due to functional and structural changes in the affected capillaries, resulting in altered permeability. Experimentally it has been shown that a hypoxic environment exists in the retina after venous occlusion. Hypoxia causes upregulation of vascular endothelial growth factor (VEGF) which is normally absent or in trace quantities in healthy human retina. There is strong evidence that the presence of VEGF increases capillary permeability. Disease states demonstrated to have hypoxia-induced elevated VEGF levels .Triamcinolone acetonide can treat the macular edema through stabilizing the blood-retinal barrier by increasing the number and/or activity of tight junctions, Nonspecificly Inhibit the pathway of the arachidonic acid ,down-regulating the vascular endothelial growth factor.Photocoagulation is a therapeutic technique using a strong light source to coagulate tissue. It has been be used for thirty years. It can block the leaky capillary nonperfusion, reduce the quantity of the retinal cells, destroying photoreceptors reduces the oxygen consumption of the outer retina and allows oxygen to diffuse from the choroid to the inner retina, where it raises the oxygen tension and relieves hypoxia and lessen VEGF or breakdown the neovascularization.so we study on the therapeutic effect through combining the intravitreal triamcinolone acetonide(IVTA) with the laser photocoagulation to treat the macular edema secondary to RVO.Methods: the study group consisting 74 eyes of 74 patients with retinal vein occlusion combined with macular edema treated with IVTA and retinal laser photocoagulation. Central Retinal Vein Occlusion is 40 eyes of 40 patients, Branch Retinal Vein Occlusion is 34 eyes of 34 patients. Exclude the patients who have the glaucoma history. All the patients treated with IVTA and Photocoagulation based on FFA. The best correct visual acuity,intraocular pressure, examination with slit lamp microscrop, fluorescein angiography and central macular thickness by optical coherence tomography were observed during the follow-up. Statistic analysis was conducted with SPSS software.Results: the age of the patients ranged from 23years to 72 years (mean,50 years).The time between RVO and treatment with intravitreal triamcinolone acetonide combined with retinal laser photocoagulation ranged from half month to 24 months (mean,3.4 months).Length of the follow-up ranged from 6 months to 18 months (mean,6.8 months). Best-corrected visual acuity was converted into logarithm of the minimal angle of resolution (logMAR). Pretreatment the BCVA was ranged from HM/15cm to 0.5,and the median best correct visual acuity of the 74 patients was 0.19+0.15(LogMAR 0.931±0.563)。At the final follow-up visit, the median best correct visual acuity of the 74 patients was 0.40±0.24(LogMAR0.49±0.30),56(75.4%) eyes of 56 patients had improved vision from baseline. 13(17.6%)eyes showed no changes, 5(6.7%)eyes had dropped vision. This difference was statisticallysignificant. Pretreatment the median Central Macular Thickness was 731.76±249.06μm ,after the treatment , the median Central Macular Thickness was obviously alleviated. This difference was statistically significant too. Elevated intraocular pressure occurred in 28 of 74 patients. Recurrence of macular edema was showed in 17 of 74 patients. cataract progression,infectious or sterile endophthalmitis,vitreous hemorrhage,glaucoma related to neovascularization and other complications were unseen.Conclusion: 1.Intravitreal triamcinolone acetonide combined with laser photocoagulation is effected to the macular edema combined with the RVO.2. The Therapeutic effect to the BRVO is more better than CRVO. 3. The best effectiveness present to the reduction of the CME and the elevation of the visual acuity was in the third month, then regressed. In a word, additional study is required to further characterize this and other risks.