Age-related macular degeneration (AMD) is a disease that occurs in adults over 50 years old and the leading cause of irreversible blindness in developed countries. AMD is characterized with a lesion of retina macular area and leads to a deterioration in central vision. Therapy aimed at combating the vascular endothelial growth factor (VEGF) resulted in an increase of corrected visual acuity in patients with neovascular age-related macular degeneration. Possible significant differences in the response to anti-VEGF therapy are due to the existence of several anti-VEGF agents with different molecular configurations. Currently, there is no consensus on classification of the optimal response or its absence with this method of treatment. In particular, there is confusion about such terms as “defendant status” after treatment with n-AMD, “tachyphylaxis” and “resistant” n-AMD. Drug tolerance is a pharmacological concept applicable to a patient’s response to a particular drug, with the physiological drug concentration is reducing in case of re-introduced. It requires the increasement the dose or frequency of drug administration to achieve the desired therapeutic effect. Tachyphylaxis is a term indicating a sudden decrease in response to a drug after its administration. This process can develop both after the initial or several administration in small doses. Tachyphylaxis develops in the background or after treatment with ranibizumab with at least two injections of the drug.Switching the treatment regimen to aflibercept or conbercept can be effective in patients resistant to bevascizumab or ranibizumab.The involvement of other pathological processes in the development mechanism of the neovascular form of AMD in addition to increased expression of VEGF dictates the need for combined therapy for this group of patients.
Aim: To analyze the effectiveness of intravitreal injection of an anti-VEGF agent (ranibizumab) and an dexametazon implant for the intravitreal injection, in real clinical life.Patients and Methods. 137 patients with MO due to retinal venous occlusion were included in the study. Patients were retrospectively divided into groups: patients who received monotherapy with ranibizumab 94 people; and monotherapy with dexamethasone implant — 15 patients; patients who initially were injected with a dexamethasone implant, but due the study transferred to ranibizumab 15 patients; patients who initially received ranibizumab, but then transferred to the dexamethasone implant -13. For the treatment of macular edema were used an anti-VEGF agent — ranibizumab (Lucentis) 0.05 ml (0.5 mg) manufactured by Novartis (Switzerland) or glucocorticosteroid — dexamethasone implant for intravitreal injection of 0.7 mg (Ozurdex) manufactured by Allergan Pharmaceutical Ireland (Ireland). The injections were administered on a pro re nata basis (the presence of macular edema). Standard ophthalmological examination and fluorescent angiography (PAG), optical coherent tomography (OCT), optical coherence tomography angiography (OCT-A) were used. Visual acuity changes (BCVA), central retinal thickness (CRT) and intraocular pressure (IOP) were analyzed depending on the study group (group 1–4), the duration of treatment and the number of injections. Results: In group 1, from 1 to 8 IVVs were performed in 24 months, an average of 3.77. In group 2, from 1 to 4 intravitreal injections were performed in 24 months, an average of 1.37. In group 3, from 1 to 2 of intravitreal injections Ozurdex and from 1 to 4 intravitreal injections of ranibizumab for 24 months. In group 4, from 1 to 4 intravitreal injections of anti-VEGF drug and from 1 to 4 intravitreal dexamethasone implant were performed in 24 months of follow-up. Monotherapy with the Ozurdex drug (12 months) had the most stable effect, with a relapse of the process, repeated injections were required, conducted only in 3 out of 15 patients. Conclusion: In real clinical practice, the dexamethasone implant showed a good safety profile and high efficacy in the resorption of macular edema in patients with retinal vein occlusion, which corresponds to the clinical trials that was made earlier.
The value of information on vascular perfusion in all layers of the central retina provided by OCT angiography is very high, which makes it useful for the detection of microvascular abnormalities in patients with retinal vein occlusions.
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