Choose the right treatment for the right patients

Age-relatedmacular degeneration (AMD) is one of themajor causes of adult visual loss. During the past decade, the use of anti-vascular endothelial growth factor (anti-VEGF) agents for the treatment of neovascular eye disease has significantly changed the standard of care in retinal medicine and ophthalmology. Intravitreal injection of anti-VEGF drugs has since been widely employed clinically to mitigate disease progression and improve the visual outcomes of affected patients. Although evidence-based data support the use of anti-VEGF pharmacotherapy in neovascular AMD, not every patient responds well to treatment. The factors contributing to the non-response include genetic factors, presence of polypoidal choroidal vasculopathy, retinal angiomatous proliferation, presence of vitreoretinal interface anomalies, or mimics of wet AMD.1e3 Some patients respond to treatment, but progress to disciform scarring, retinal pigment epithelial (RPE) tears, massive subretinal hemorrhage, geographic atrophy, or develop tachyphylaxis to anti-VEGF drugs.4 While there is argument about the timing associated with the decision of a responder to accept treatment, it would be helpful for AMD patients if the efficacy of anti-VEGF could be determined as early as possible in their treatment, so that non-responders could begin other more appropriate therapy. Evidence showed that most diseases require long-term treatments to maintain the beneficial effects of the therapy, therefore, the treatment burden is substantial for both patients and doctors.5e7 Hence, it is important to choose the appropriate therapy for an individual patient from the beginning. Macular telangiectasia type 2 (Mac Tel 2) is an important mimics of wet AMD. In this issue of the Taiwan Journal of Ophthalmology, Wu8 contributes a comprehensive review of Mac Tel 2. Mac Tel 2, also known as idiopathic perifoveal telangiectasia and juxtafoveolar retinal telangiectasis type 2A, is an enigmatic disease of unknown etiology that manifests both neurodegenerative and vasculopathic characteristics during the fifth or sixth decades of life. Clinical characteristics include minimally dilated parafoveal capillaries with loss of retinal transparency in the area involved, absence of lipid exudation, right-angled retinal venules, superficial retinal refractile deposits, hyperplasia of the RPE, foveal atrophy, and choroidal neovacularization (CNV). Optical coherent tomography (OCT) images typically demonstrate outer retinal abnormalities and the presence of intraretinal hyporeflective spaces that are usually not related with retinal thickening or fluorescein leakage. The typical fluorescein angiographic finding is a deep intraretinal hyperfluorescent staining in the temporal parafoveal area. Over time, this fluorescein hyperfluorescence involves the entire parafoveal area, but does not extend to the center of the fovea. Long-term prognosis for central vision is poor due to the development of CNV or macular atrophy. Its pathogenesis remains unclear, however, multimodality imaging with fluorescein angiography, spectral domain optical coherence tomography, adaptive optics, confocal blue reflectance, short-wave fundus autofluorescence, OCT angiography, and clinicopathological correlations implicate Müller cells. Currently there is no known treatment for this condition, unless in the presence of CNV. The eyes of these patients may benefit from anti-VEGF treatment.9 It is important to choose the right treatment at the right stage of Mac Tel 2. Otherwise, inaction may increase the treatment-related risk and burden. OCT is a non-invasive imaging modality that shows crosssectional images of the retina, RPE, and choroid. The recently developed OCT angiography provides the opportunity to study retinal vasculature without the need for dye injection. OCT angiography offered an even better tool to investigate the anatomical changes associated with Mac Tel 2 and is expected to be a useful guide for treatment. This treatment demonstrates that the earliest vascular changes associated with Mac Tel 2 arise in the outer deep capillary plexus.10,11 As the disease progresses, the vascular changes also involve the inner superficial plexus, albeit to a lesser extent than the changes seen in the outer plexus.11 The vessels appear less densely packed, thinner, and in an abnormal arrangement. The normally avascular Henle's layer and the outer nuclear layers becomes the target of a vascular invasion. Anastomosis between plexi and dragging of vessels temporally are also observed by OCT angiography.10 Patients withMac Tel 2 could be monitored closely to catch the right time for intervention. Several ocular factors had been reportedly related to AMD progress.2,3 In this issue of the Taiwan Journal of Ophthalmology, Lai et al12 report the relationship of distinct reduced subfoveal choroidal thickness (SFCT) and elongated axial length (AL) with late AMD. A total of 856 eyes of 486 patients (older than 65 years), including 400 eyes at various AMD stages and 456 eyes with no Conflicts of interest: The author declares no conflicts of interest.