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To date, there is no known effective treatment for the non-proliferative form of macular telangiectasia type 2.
Treatment options are limited. No treatment has to date been shown to prevent progression. The variable course of progression of the disease makes it difficult to assess the efficacy of treatments. Retinal laser photocoagulation is not helpful. In fact, laser therapy may actually enhance vessel ectasia and promote intraretinal fibrosis in these individuals. It is hoped that a better understanding of the pathogenesis of the disease may lead to better treatments.
The use of vascular endothelial growth factor (VEGF) inhibitors, which have proven so successful in treating age-related macular degeneration, have not proven to be effective in non-proliferative MacTel type 2. Ranibizumab reduces the vascular leak seen on angiography, although microperimetry suggests that neural atrophy may still proceed in treated eyes.In proliferative stages (neovascularisation), treatment with Anti-VEGF can be helpful.
CNTF is believed to have neuroprotective properties and could thus be able to slow down the progression of MacTel type 2. It has been shown to be safe to use in MacTel patients in a phase 1 safety trial.
The most crucial aspect of managing patients with macular telangiectasia is recognition of the clinical signs. This condition is relatively uncommon: hence, many practitioners may not be familiar with or experienced in diagnosing the disorder. MacTel must be part of the differential in any case of idiopathic paramacular hemorrhage, vasculopathy, macular edema or focal pigment hypertrophy, especially in those patients without a history of retinopathy or contributory systemic disease.
Treatment options for macular telangiectasia type 1 include laser photocoagulation, intra-vitreal injections of steroids, or anti-vascular endothelial growth factor (anti-VEGF) agents. Photocoagulation was recommended by Gass and remains to date the mainstay of treatment. It seems to be successful in causing resolution of exudation and VA improvement or stabilization in selected patients. Photocoagulation should be used sparingly to reduce the chance of producing a symptomatic paracentral scotoma and metamorphopsia. Small burns (100–200 μm) of moderate intensity in a grid-pattern and on multiple occasions, if necessary, are recommended. It is unnecessary to destroy every dilated capillary, and, particularly during the initial session of photocoagulation, those on the edge of the capillary-free zone should be avoided.
Intravitreal injections of triamcinolone acetonide (IVTA) which have proved to be beneficial in the treatment of macular edema by their anti-inflammatory effect, their downregulation of VEGF production, and stabilization of the blood retinal barrier were reported anecdotally in the management of macular telangiectasia type 1. In two case reports, IVTA of 4 mg allowed a transitory reduction of retinal edema, with variable or no increase in VA. As expected with all IVTA injections, the edema recurred within 3–6 months, and no permanent improvement could be shown.14,15 In general, the effect of IVTA is short-lived and complications, mainly increased intraocular pressure and cataract, limit its use.
Indocyanine green angiography-guided laser photocoagulation directed at the leaky microaneurysms and vessels combined with sub-Tenon’s capsule injection of triamcinolone acetonide has also been reported in a limited number of patients with macular telangiectasia type 1 with improvement or stabilization of vision after a mean follow-up of 10 months.16 Further studies are needed to assess the efficacy of this treatment modality.
Recently, intravitreal injections of anti-VEGF agents, namely bevacizumab, a humanized monoclonal antibody targeted against pro-angiogenic, circulatory VEGF, and ranibizumab, a FDA-approved monoclonal antibody fragment that targets all VEGF-A isoforms, have shown improved visual outcome and reduced leakage in macular edema form diabetes and retinal venous occlusions. In one reported patient with macular telangiectasia type 1, a single intravitreal bevacizumab injection resulted in a marked increase in VA from 20/50 to 20/20, with significant and sustained decrease in both leakage on FA and cystoid macular edema on OCT up to 12 months. It is likely that patients with macular telangiectasia type 1 with pronounced macular edema from leaky telangiectasis may benefit functionally and morphologically from intravitreal anti-VEGF injections, but this warrants further studies.
Today, laser photocoagulation remains mostly effective, but the optimal treatment of macular telangiectasia type 1 is questioned, and larger series comparing different treatment modalities seem warranted. The rarity of the disease however, makes it difficult to assess in a controlled randomized manner.
However, these treatment modalities should be considered only in cases of marked and rapid vision loss secondary to macular edema or CNV. Otherwise, a conservative approach is recommended, since many of these patients will stabilize without intervention.