Treatment of myopic CNV

Myopic CNV with haemorrhage. Image courtesy of Adrian Koh MD, FRCS The availability of anti-VEGF agents, such as intravitreal ranibizumab (Lucentis, Genentech), has revolutionised the management of various forms of ocular neovascularisation, including myopic CNV (mCNV), according to Professor Adrian Koh MD, FRCS. “The current gold standard treatment of myopic CNV is anti-VEGF therapy, which achieves good visual results with minimal number of treatments, unlike in age-related macular degeneration CNV,” Prof Koh said at the 17th EURETINA Congress in Barcelona. Myopic CNV is a sight-threatening complication of pathologic myopia characterised by neurosensory detachments and sub-retinal haemorrhage with fibrotic membrane formation, said Prof Koh. “In individuals with pathologic myopia, CNV will develop in approximately 5% of eyes in Caucasians and approximately 10% in Asians,” he said. Several theories have been put forward to explain the cause of mCNV, said Prof Koh. The mechanical theory posits that excessive elongation of the retina and associated changes cause an imbalance of angiogenic and antiangiogenic factors, thereby triggering the condition. The heredodegenerative theory argues that refractive errors are genetically predetermined, while the hemodynamic theory proposes perfusion changes in the choroidal circulation of the myopic eye as a possible cause. Standard tests for diagnosing mCNV include fundus biomicroscopy, fluorescein angiography and optical coherence tomography (OCT). Fluorescein angiography, which demonstrates leakage from the CNV, is still the current gold standard for diagnosis, said Prof Koh. Prior to the introduction of anti-VEGF agents, verteporfin photodynamic therapy (vPDT) was the only approved treatment for mCNV, said Prof Koh. “PDT was shown to have a benefit over placebo for up to two years and may delay further visual acuity deterioration. However, it does not improve vision, it may induce chorioretinal damage and leakage from CNV may persist,” he said. The introduction of anti-VEGF treatments changed the paradigm for mCNV management. In the RADIANCE trial, ranibizumab demonstrated a 13-to-14 letter gain with a median of just two injections, said Prof Koh. More than 50% of patients treated with ranibizumab gained more than 15 letters at month 12, and the proportion of patients with CNV leakage and intraretinal oedema decreased by more than 70% in ranibizumab groups. A recent trial of intravitreal aflibercept (EYLEA, Bayer Pharma AG) for mCNV demonstrated clinically important visual and anatomic benefits with limited injections, concluded Prof Koh. Adrian Koh: dradriankoh@eyeretinasurgeons.com